Merge remote-tracking branch 'upstream/master' into mix_20240309

22 files changed, 1379 insertions, 573 deletions

diff --git a/test/functional/plugin/ccomplete_spec.lua b/test/functional/plugin/ccomplete_spec.lua
index 903f16fc73..4c4c5e9444 100644
--- a/test/functional/plugin/ccomplete_spec.lua
+++ b/test/functional/plugin/ccomplete_spec.lua
@@ -1,10 +1,12 @@
-local helpers = require('test.functional.helpers')(after_each)
-local clear = helpers.clear
-local command = helpers.command
-local eq = helpers.eq
-local eval = helpers.eval
-local feed = helpers.feed
-local write_file = helpers.write_file
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear = n.clear
+local command = n.command
+local eq = t.eq
+local eval = n.eval
+local feed = n.feed
+local write_file = t.write_file
 
 describe('ccomplete#Complete', function()
   setup(function()
diff --git a/test/functional/plugin/cfilter_spec.lua b/test/functional/plugin/cfilter_spec.lua
index 37261d59df..220404a934 100644
--- a/test/functional/plugin/cfilter_spec.lua
+++ b/test/functional/plugin/cfilter_spec.lua
@@ -1,8 +1,10 @@
-local helpers = require('test.functional.helpers')(after_each)
-local clear = helpers.clear
-local command = helpers.command
-local eq = helpers.eq
-local fn = helpers.fn
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear = n.clear
+local command = n.command
+local eq = t.eq
+local fn = n.fn
 
 describe('cfilter.lua', function()
   before_each(function()
diff --git a/test/functional/plugin/editorconfig_spec.lua b/test/functional/plugin/editorconfig_spec.lua
index 115c28fbf6..839a723405 100644
--- a/test/functional/plugin/editorconfig_spec.lua
+++ b/test/functional/plugin/editorconfig_spec.lua
@@ -1,14 +1,18 @@
-local helpers = require('test.functional.helpers')(after_each)
-local clear = helpers.clear
-local command = helpers.command
-local eq = helpers.eq
-local pathsep = helpers.get_pathsep()
-local fn = helpers.fn
-local api = helpers.api
-local exec_lua = helpers.exec_lua
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear = n.clear
+local command = n.command
+local eq = t.eq
+local pathsep = n.get_pathsep()
+local fn = n.fn
+local api = n.api
+local exec_lua = n.exec_lua
 
 local testdir = 'Xtest-editorconfig'
 
+--- @param name string
+--- @param expected table<string,any>
 local function test_case(name, expected)
   local filename = testdir .. pathsep .. name
   command('edit ' .. filename)
@@ -18,8 +22,8 @@ local function test_case(name, expected)
 end
 
 setup(function()
-  helpers.mkdir_p(testdir)
-  helpers.write_file(
+  n.mkdir_p(testdir)
+  t.write_file(
     testdir .. pathsep .. '.editorconfig',
     [[
     root = true
@@ -94,7 +98,7 @@ setup(function()
 end)
 
 teardown(function()
-  helpers.rmdir(testdir)
+  n.rmdir(testdir)
 end)
 
 describe('editorconfig', function()
@@ -176,18 +180,18 @@ But not this one
     -- luacheck: pop
     local trimmed = untrimmed:gsub('%s+\n', '\n')
 
-    helpers.write_file(filename, untrimmed)
+    t.write_file(filename, untrimmed)
     command('edit ' .. filename)
     command('write')
     command('bdelete')
-    eq(trimmed, helpers.read_file(filename))
+    eq(trimmed, t.read_file(filename))
 
     filename = testdir .. pathsep .. 'no_trim.txt'
-    helpers.write_file(filename, untrimmed)
+    t.write_file(filename, untrimmed)
     command('edit ' .. filename)
     command('write')
     command('bdelete')
-    eq(untrimmed, helpers.read_file(filename))
+    eq(untrimmed, t.read_file(filename))
   end)
 
   it('sets textwidth', function()
diff --git a/test/functional/plugin/health_spec.lua b/test/functional/plugin/health_spec.lua
index 8564ec7c9b..9c7c953fb0 100644
--- a/test/functional/plugin/health_spec.lua
+++ b/test/functional/plugin/health_spec.lua
@@ -1,14 +1,18 @@
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
-local clear = helpers.clear
-local curbuf_contents = helpers.curbuf_contents
-local command = helpers.command
-local eq, neq, matches = helpers.eq, helpers.neq, helpers.matches
-local getcompletion = helpers.fn.getcompletion
-local insert = helpers.insert
-local source = helpers.source
-local exec_lua = helpers.exec_lua
+local clear = n.clear
+local curbuf_contents = n.curbuf_contents
+local command = n.command
+local eq, matches = t.eq, t.matches
+local getcompletion = n.fn.getcompletion
+local insert = n.insert
+local exec_lua = n.exec_lua
+local source = n.source
+local assert_alive = n.assert_alive
+local fn = n.fn
+local api = n.api
 
 describe(':checkhealth', function()
   it('detects invalid $VIMRUNTIME', function()
@@ -19,6 +23,7 @@ describe(':checkhealth', function()
     eq(false, status)
     eq('Invalid $VIMRUNTIME: bogus', string.match(err, 'Invalid.*'))
   end)
+
   it("detects invalid 'runtimepath'", function()
     clear()
     command('set runtimepath=bogus')
@@ -26,19 +31,29 @@ describe(':checkhealth', function()
     eq(false, status)
     eq("Invalid 'runtimepath'", string.match(err, 'Invalid.*'))
   end)
+
   it('detects invalid $VIM', function()
     clear()
     -- Do this after startup, otherwise it just breaks $VIMRUNTIME.
     command("let $VIM='zub'")
-    command('checkhealth nvim')
+    command('checkhealth vim.health')
     matches('ERROR $VIM .* zub', curbuf_contents())
   end)
+
   it('completions can be listed via getcompletion()', function()
     clear()
-    eq('nvim', getcompletion('nvim', 'checkhealth')[1])
-    eq('provider.clipboard', getcompletion('prov', 'checkhealth')[1])
+    eq('vim.deprecated', getcompletion('vim', 'checkhealth')[1])
+    eq('vim.provider', getcompletion('vim.prov', 'checkhealth')[1])
     eq('vim.lsp', getcompletion('vim.ls', 'checkhealth')[1])
-    neq('vim', getcompletion('^vim', 'checkhealth')[1]) -- should not complete vim.health
+  end)
+
+  it('completion checks for vim.health._complete() return type #28456', function()
+    clear()
+    exec_lua([[vim.health._complete = function() return 1 end]])
+    eq({}, getcompletion('', 'checkhealth'))
+    exec_lua([[vim.health._complete = function() return { 1 } end]])
+    eq({}, getcompletion('', 'checkhealth'))
+    assert_alive()
   end)
 end)
 
@@ -52,7 +67,7 @@ describe('health.vim', function()
   describe(':checkhealth', function()
     it('functions report_*() render correctly', function()
       command('checkhealth full_render')
-      helpers.expect([[
+      n.expect([[
 
       ==============================================================================
       test_plug.full_render: require("test_plug.full_render.health").check()
@@ -75,7 +90,7 @@ describe('health.vim', function()
 
     it('concatenates multiple reports', function()
       command('checkhealth success1 success2 test_plug')
-      helpers.expect([[
+      n.expect([[
 
         ==============================================================================
         test_plug: require("test_plug.health").check()
@@ -105,7 +120,7 @@ describe('health.vim', function()
 
     it('lua plugins submodules', function()
       command('checkhealth test_plug.submodule')
-      helpers.expect([[
+      n.expect([[
 
         ==============================================================================
         test_plug.submodule: require("test_plug.submodule.health").check()
@@ -120,7 +135,7 @@ describe('health.vim', function()
 
     it('... including empty reports', function()
       command('checkhealth test_plug.submodule_empty')
-      helpers.expect([[
+      n.expect([[
 
       ==============================================================================
       test_plug.submodule_empty: require("test_plug.submodule_empty.health").check()
@@ -158,28 +173,10 @@ describe('health.vim', function()
       }
     end)
 
-    it('fold healthchecks', function()
-      local screen = Screen.new(50, 7)
-      screen:attach()
-      command('checkhealth foo success1')
-      command('set nowrap laststatus=0')
-      screen:expect {
-        grid = [[
-        ^                                                  |
-        ──────────────────────────────────────────────────|
-        +WE  4 lines: foo: ·······························|
-        ──────────────────────────────────────────────────|
-        +--  8 lines: test_plug.success1: require("test_pl|
-        ~                                                 |
-                                                          |
-      ]],
-      }
-    end)
-
     it('gracefully handles invalid healthcheck', function()
       command('checkhealth non_existent_healthcheck')
       -- luacheck: ignore 613
-      helpers.expect([[
+      n.expect([[
 
         ==============================================================================
         non_existent_healthcheck: 
@@ -191,7 +188,7 @@ describe('health.vim', function()
     it('does not use vim.health as a healtcheck', function()
       -- vim.health is not a healthcheck
       command('checkhealth vim')
-      helpers.expect([[
+      n.expect([[
       ERROR: No healthchecks found.]])
     end)
   end)
@@ -218,6 +215,12 @@ describe(':checkhealth window', function()
 
   it('opens directly if no buffer created', function()
     local screen = Screen.new(50, 12)
+    screen:set_default_attr_ids {
+      [1] = { foreground = Screen.colors.Blue, bold = true },
+      [14] = { foreground = Screen.colors.LightGrey, background = Screen.colors.DarkGray },
+      [31] = { foreground = tonumber('0x6a0dad') },
+      [32] = { foreground = Screen.colors.PaleGreen2 },
+    }
     screen:attach({ ext_multigrid = true })
     command('checkhealth success1')
     screen:expect {
@@ -227,16 +230,16 @@ describe(':checkhealth window', function()
       [3:--------------------------------------------------]|
     ## grid 2
       ^                                                  |
-      ──────────────────────────────────────────────────|
-      ────────────────────────────                      |
-      test_plug.success1: require("test_plug.success1.  |
-      health").check()                                  |
+      {14:──────────────────────────────────────────────────}|
+      {14:────────────────────────────}                      |
+      {31:test_plug.success1: require("test_plug.success1.  }|
+      {31:health").check()}                                  |
                                                         |
-      report 1                                          |
-      - OK everything is fine                           |
+      {31:report 1}                                          |
+      - {32:OK} everything is fine                           |
                                                         |
-      report 2                                          |
-      - OK nothing to see here                          |
+      {31:report 2}                                          |
+      - {32:OK} nothing to see here                          |
     ## grid 3
                                                         |
     ]],
@@ -245,6 +248,12 @@ describe(':checkhealth window', function()
 
   local function test_health_vsplit(left, emptybuf, mods)
     local screen = Screen.new(50, 20)
+    screen:set_default_attr_ids {
+      [1] = { foreground = Screen.colors.Blue, bold = true },
+      [14] = { foreground = Screen.colors.LightGrey, background = Screen.colors.DarkGray },
+      [31] = { foreground = tonumber('0x6a0dad') },
+      [32] = { foreground = Screen.colors.PaleGreen2 },
+    }
     screen:attach({ ext_multigrid = true })
     if not emptybuf then
       insert('hello')
@@ -257,24 +266,24 @@ describe(':checkhealth window', function()
       [3:--------------------------------------------------]|
     ## grid 2
       %s                   |
-      ~                       |*18
+      {1:~                       }|*18
     ## grid 3
                                                         |
     ## grid 4
       ^                         |
-      ─────────────────────────|*3
-      ───                      |
-      test_plug.success1:      |
-      require("test_plug.      |
-      success1.health").check()|
+      {14:─────────────────────────}|*3
+      {14:───}                      |
+      {31:test_plug.success1:      }|
+      {31:require("test_plug.      }|
+      {31:success1.health").check()}|
                                |
-      report 1                 |
-      - OK everything is fine  |
+      {31:report 1}                 |
+      - {32:OK} everything is fine  |
                                |
-      report 2                 |
-      - OK nothing to see here |
+      {31:report 2}                 |
+      - {32:OK} nothing to see here |
                                |
-      ~                        |*4
+      {1:~                        }|*4
     ]]):format(
         left and '[4:-------------------------]│[2:------------------------]|*19'
           or '[2:------------------------]│[4:-------------------------]|*19',
@@ -304,6 +313,7 @@ describe(':checkhealth window', function()
   local function test_health_split(top, emptybuf, mods)
     local screen = Screen.new(50, 25)
     screen:attach({ ext_multigrid = true })
+    screen._default_attr_ids = nil
     if not emptybuf then
       insert('hello')
     end
@@ -368,7 +378,7 @@ describe(':checkhealth window', function()
 
   it('opens in tab', function()
     -- create an empty buffer called "my_buff"
-    exec_lua 'vim.api.nvim_create_buf(false, true)'
+    api.nvim_create_buf(false, true)
     command('file my_buff')
     command('checkhealth success1')
     -- define a function that collects all buffers in each tab
@@ -387,7 +397,7 @@ describe(':checkhealth window', function()
                 return buffs
         endfunction
     ]])
-    local buffers_per_tab = exec_lua('return vim.fn.CollectBuffersPerTab()')
+    local buffers_per_tab = fn.CollectBuffersPerTab()
     eq(buffers_per_tab, { tab1 = { 'my_buff' }, tab2 = { 'health://' } })
   end)
 end)
diff --git a/test/functional/plugin/lsp/codelens_spec.lua b/test/functional/plugin/lsp/codelens_spec.lua
index 29daf7a066..cd20e95dd1 100644
--- a/test/functional/plugin/lsp/codelens_spec.lua
+++ b/test/functional/plugin/lsp/codelens_spec.lua
@@ -1,14 +1,15 @@
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local exec_lua = helpers.exec_lua
-local eq = helpers.eq
+local exec_lua = n.exec_lua
+local eq = t.eq
 
 describe('vim.lsp.codelens', function()
   before_each(function()
-    helpers.clear()
+    n.clear()
     exec_lua('require("vim.lsp")')
   end)
-  after_each(helpers.clear)
+  after_each(n.clear)
 
   it('on_codelens_stores_and_displays_lenses', function()
     local fake_uri = 'file:///fake/uri'
diff --git a/test/functional/plugin/lsp/completion_spec.lua b/test/functional/plugin/lsp/completion_spec.lua
index 655eb76be6..2798d57381 100644
--- a/test/functional/plugin/lsp/completion_spec.lua
+++ b/test/functional/plugin/lsp/completion_spec.lua
@@ -1,7 +1,9 @@
 ---@diagnostic disable: no-unknown
-local helpers = require('test.functional.helpers')(after_each)
-local eq = helpers.eq
-local exec_lua = helpers.exec_lua
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local eq = t.eq
+local exec_lua = n.exec_lua
 
 --- Convert completion results.
 ---
@@ -41,7 +43,7 @@ local function complete(line, candidates, lnum)
 end
 
 describe('vim.lsp._completion', function()
-  before_each(helpers.clear)
+  before_each(n.clear)
 
   -- https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocument_completion
   it('prefers textEdit over label as word', function()
diff --git a/test/functional/plugin/lsp/diagnostic_spec.lua b/test/functional/plugin/lsp/diagnostic_spec.lua
index 705c182df7..c5e14ffdc2 100644
--- a/test/functional/plugin/lsp/diagnostic_spec.lua
+++ b/test/functional/plugin/lsp/diagnostic_spec.lua
@@ -1,12 +1,14 @@
-local helpers = require('test.functional.helpers')(after_each)
-local lsp_helpers = require('test.functional.plugin.lsp.helpers')
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local clear = helpers.clear
-local exec_lua = helpers.exec_lua
-local eq = helpers.eq
-local neq = require('test.helpers').neq
+local t_lsp = require('test.functional.plugin.lsp.testutil')
 
-local create_server_definition = lsp_helpers.create_server_definition
+local clear = n.clear
+local exec_lua = n.exec_lua
+local eq = t.eq
+local neq = t.neq
+
+local create_server_definition = t_lsp.create_server_definition
 
 describe('vim.lsp.diagnostic', function()
   local fake_uri
@@ -257,7 +259,7 @@ describe('vim.lsp.diagnostic', function()
         }, {client_id=client_id})
         return vim.fn.bufnr(vim.uri_to_fname("file:///fake/uri2"))
       ]]
-      eq(bufnr, -1)
+      eq(-1, bufnr)
 
       -- Create buffer on diagnostics
       bufnr = exec_lua [[
@@ -269,8 +271,8 @@ describe('vim.lsp.diagnostic', function()
         }, {client_id=client_id})
         return vim.fn.bufnr(vim.uri_to_fname("file:///fake/uri2"))
       ]]
-      neq(bufnr, -1)
-      eq(exec_lua([[return #vim.diagnostic.get(...)]], bufnr), 1)
+      neq(-1, bufnr)
+      eq(1, exec_lua([[return #vim.diagnostic.get(...)]], bufnr))
 
       -- Clear diagnostics after buffer was created
       bufnr = exec_lua [[
@@ -280,8 +282,8 @@ describe('vim.lsp.diagnostic', function()
         }, {client_id=client_id})
         return vim.fn.bufnr(vim.uri_to_fname("file:///fake/uri2"))
       ]]
-      neq(bufnr, -1)
-      eq(exec_lua([[return #vim.diagnostic.get(...)]], bufnr), 0)
+      neq(-1, bufnr)
+      eq(0, exec_lua([[return #vim.diagnostic.get(...)]], bufnr))
     end)
   end)
 
diff --git a/test/functional/plugin/lsp/handler_spec.lua b/test/functional/plugin/lsp/handler_spec.lua
index 56e29e7337..013a5fb5e7 100644
--- a/test/functional/plugin/lsp/handler_spec.lua
+++ b/test/functional/plugin/lsp/handler_spec.lua
@@ -1,9 +1,10 @@
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local eq = helpers.eq
-local exec_lua = helpers.exec_lua
-local pcall_err = helpers.pcall_err
-local matches = helpers.matches
+local eq = t.eq
+local exec_lua = n.exec_lua
+local pcall_err = t.pcall_err
+local matches = t.matches
 
 describe('lsp-handlers', function()
   describe('vim.lsp._with_extend', function()
diff --git a/test/functional/plugin/lsp/incremental_sync_spec.lua b/test/functional/plugin/lsp/incremental_sync_spec.lua
index bd1842ceb5..238b90b57d 100644
--- a/test/functional/plugin/lsp/incremental_sync_spec.lua
+++ b/test/functional/plugin/lsp/incremental_sync_spec.lua
@@ -1,11 +1,12 @@
 -- Test suite for testing interactions with the incremental sync algorithms powering the LSP client
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local api = helpers.api
-local clear = helpers.clear
-local eq = helpers.eq
-local exec_lua = helpers.exec_lua
-local feed = helpers.feed
+local api = n.api
+local clear = n.clear
+local eq = t.eq
+local exec_lua = n.exec_lua
+local feed = n.feed
 
 before_each(function()
   clear()
diff --git a/test/functional/plugin/lsp/inlay_hint_spec.lua b/test/functional/plugin/lsp/inlay_hint_spec.lua
index 192797b312..d3b5ae0e4e 100644
--- a/test/functional/plugin/lsp/inlay_hint_spec.lua
+++ b/test/functional/plugin/lsp/inlay_hint_spec.lua
@@ -1,14 +1,16 @@
-local helpers = require('test.functional.helpers')(after_each)
-local lsp_helpers = require('test.functional.plugin.lsp.helpers')
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
+local t_lsp = require('test.functional.plugin.lsp.testutil')
 
-local eq = helpers.eq
-local dedent = helpers.dedent
-local exec_lua = helpers.exec_lua
-local insert = helpers.insert
+local eq = t.eq
+local dedent = t.dedent
+local exec_lua = n.exec_lua
+local insert = n.insert
+local api = n.api
 
-local clear_notrace = lsp_helpers.clear_notrace
-local create_server_definition = lsp_helpers.create_server_definition
+local clear_notrace = t_lsp.clear_notrace
+local create_server_definition = t_lsp.create_server_definition
 
 local text = dedent([[
 auto add(int a, int b) { return a + b; }
@@ -41,12 +43,12 @@ local grid_without_inlay_hints = [[
 ]]
 
 local grid_with_inlay_hints = [[
-  auto add(int a, int b)-> int { return a + b; }    |
+  auto add(int a, int b){1:-> int} { return a + b; }    |
                                                     |
   int main() {                                      |
       int x = 1;                                    |
       int y = 2;                                    |
-      return add(a: x,b: y);                        |
+      return add({1:a:} x,{1:b:} y);                        |
   }                                                 |
   ^}                                                 |
                                                     |
@@ -68,8 +70,8 @@ before_each(function()
         inlayHintProvider = true,
       },
       handlers = {
-        ['textDocument/inlayHint'] = function()
-          return vim.json.decode(response)
+        ['textDocument/inlayHint'] = function(_, _, callback)
+          callback(nil, vim.json.decode(response))
         end,
       }
     })
@@ -83,12 +85,12 @@ before_each(function()
   )
 
   insert(text)
-  exec_lua([[vim.lsp.inlay_hint.enable(bufnr)]])
+  exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })]])
   screen:expect({ grid = grid_with_inlay_hints })
 end)
 
 after_each(function()
-  exec_lua("vim.api.nvim_exec_autocmds('VimLeavePre', { modeline = false })")
+  api.nvim_exec_autocmds('VimLeavePre', { modeline = false })
 end)
 
 describe('vim.lsp.inlay_hint', function()
@@ -104,13 +106,13 @@ describe('vim.lsp.inlay_hint', function()
           inlayHintProvider = true,
         },
         handlers = {
-          ['textDocument/inlayHint'] = function()
-            return {}
+          ['textDocument/inlayHint'] = function(_, _, callback)
+            callback(nil, {})
           end,
         }
       })
       client2 = vim.lsp.start({ name = 'dummy2', cmd = server2.cmd })
-      vim.lsp.inlay_hint.enable(bufnr)
+      vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })
     ]])
 
     exec_lua([[ vim.lsp.stop_client(client2) ]])
@@ -118,18 +120,66 @@ describe('vim.lsp.inlay_hint', function()
   end)
 
   describe('enable()', function()
-    it('clears/applies inlay hints when passed false/true/nil', function()
-      exec_lua([[vim.lsp.inlay_hint.enable(bufnr, false)]])
-      screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
+    it('validation', function()
+      t.matches(
+        'enable: expected boolean, got table',
+        t.pcall_err(exec_lua, [[vim.lsp.inlay_hint.enable({}, { bufnr = bufnr })]])
+      )
+      t.matches(
+        'enable: expected boolean, got number',
+        t.pcall_err(exec_lua, [[vim.lsp.inlay_hint.enable(42)]])
+      )
+      t.matches(
+        'filter: expected table, got number',
+        t.pcall_err(exec_lua, [[vim.lsp.inlay_hint.enable(true, 42)]])
+      )
+    end)
+
+    describe('clears/applies inlay hints when passed false/true/nil', function()
+      before_each(function()
+        exec_lua([[
+          bufnr2 = vim.api.nvim_create_buf(true, false)
+          vim.lsp.buf_attach_client(bufnr2, client_id)
+          vim.api.nvim_win_set_buf(0, bufnr2)
+        ]])
+        insert(text)
+        exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr2 })]])
+        exec_lua([[vim.api.nvim_win_set_buf(0, bufnr)]])
+        screen:expect({ grid = grid_with_inlay_hints })
+      end)
+
+      it('for one single buffer', function()
+        exec_lua([[
+          vim.lsp.inlay_hint.enable(false, { bufnr = bufnr })
+          vim.api.nvim_win_set_buf(0, bufnr2)
+        ]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+        exec_lua([[vim.api.nvim_win_set_buf(0, bufnr)]])
+        screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
 
-      exec_lua([[vim.lsp.inlay_hint.enable(bufnr, true)]])
-      screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+        exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
 
-      exec_lua([[vim.lsp.inlay_hint.enable(bufnr, not vim.lsp.inlay_hint.is_enabled(bufnr))]])
-      screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
+        exec_lua(
+          [[vim.lsp.inlay_hint.enable(not vim.lsp.inlay_hint.is_enabled({ bufnr = bufnr }), { bufnr = bufnr })]]
+        )
+        screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
 
-      exec_lua([[vim.lsp.inlay_hint.enable(bufnr)]])
-      screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+        exec_lua([[vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+      end)
+
+      it('for all buffers', function()
+        exec_lua([[vim.lsp.inlay_hint.enable(false)]])
+        screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
+        exec_lua([[vim.api.nvim_win_set_buf(0, bufnr2)]])
+        screen:expect({ grid = grid_without_inlay_hints, unchanged = true })
+
+        exec_lua([[vim.lsp.inlay_hint.enable(true)]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+        exec_lua([[vim.api.nvim_win_set_buf(0, bufnr)]])
+        screen:expect({ grid = grid_with_inlay_hints, unchanged = true })
+      end)
     end)
   end)
 
@@ -156,25 +206,25 @@ describe('vim.lsp.inlay_hint', function()
             inlayHintProvider = true,
           },
           handlers = {
-            ['textDocument/inlayHint'] = function()
-              return { expected2 }
+            ['textDocument/inlayHint'] = function(_, _, callback)
+              callback(nil, { expected2 })
             end,
           }
         })
         client2 = vim.lsp.start({ name = 'dummy2', cmd = server2.cmd })
-        vim.lsp.inlay_hint.enable(bufnr)
+        vim.lsp.inlay_hint.enable(true, { bufnr = bufnr })
       ]],
         expected2
       )
 
       --- @type vim.lsp.inlay_hint.get.ret
       local res = exec_lua([[return vim.lsp.inlay_hint.get()]])
-      eq(res, {
+      eq({
         { bufnr = 1, client_id = 1, inlay_hint = expected[1] },
         { bufnr = 1, client_id = 1, inlay_hint = expected[2] },
         { bufnr = 1, client_id = 1, inlay_hint = expected[3] },
         { bufnr = 1, client_id = 2, inlay_hint = expected2 },
-      })
+      }, res)
 
       --- @type vim.lsp.inlay_hint.get.ret
       res = exec_lua([[return vim.lsp.inlay_hint.get({
@@ -183,9 +233,9 @@ describe('vim.lsp.inlay_hint', function()
           ["end"] = { line = 2, character = 10 },
         },
       })]])
-      eq(res, {
+      eq({
         { bufnr = 1, client_id = 2, inlay_hint = expected2 },
-      })
+      }, res)
 
       --- @type vim.lsp.inlay_hint.get.ret
       res = exec_lua([[return vim.lsp.inlay_hint.get({
@@ -195,16 +245,16 @@ describe('vim.lsp.inlay_hint', function()
           ["end"] = { line = 5, character = 17 },
         },
       })]])
-      eq(res, {
+      eq({
         { bufnr = 1, client_id = 1, inlay_hint = expected[2] },
         { bufnr = 1, client_id = 1, inlay_hint = expected[3] },
-      })
+      }, res)
 
       --- @type vim.lsp.inlay_hint.get.ret
       res = exec_lua([[return vim.lsp.inlay_hint.get({
         bufnr = vim.api.nvim_get_current_buf() + 1,
       })]])
-      eq(res, {})
+      eq({}, res)
     end)
   end)
 end)
diff --git a/test/functional/plugin/lsp/semantic_tokens_spec.lua b/test/functional/plugin/lsp/semantic_tokens_spec.lua
index 77e39c81c8..7908c5d2e7 100644
--- a/test/functional/plugin/lsp/semantic_tokens_spec.lua
+++ b/test/functional/plugin/lsp/semantic_tokens_spec.lua
@@ -1,25 +1,27 @@
-local helpers = require('test.functional.helpers')(after_each)
-local lsp_helpers = require('test.functional.plugin.lsp.helpers')
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
+local t_lsp = require('test.functional.plugin.lsp.testutil')
 
-local command = helpers.command
-local dedent = helpers.dedent
-local eq = helpers.eq
-local exec_lua = helpers.exec_lua
-local feed = helpers.feed
-local feed_command = helpers.feed_command
-local insert = helpers.insert
-local matches = helpers.matches
+local command = n.command
+local dedent = t.dedent
+local eq = t.eq
+local exec_lua = n.exec_lua
+local feed = n.feed
+local feed_command = n.feed_command
+local insert = n.insert
+local matches = t.matches
+local api = n.api
 
-local clear_notrace = lsp_helpers.clear_notrace
-local create_server_definition = lsp_helpers.create_server_definition
+local clear_notrace = t_lsp.clear_notrace
+local create_server_definition = t_lsp.create_server_definition
 
 before_each(function()
   clear_notrace()
 end)
 
 after_each(function()
-  exec_lua("vim.api.nvim_exec_autocmds('VimLeavePre', { modeline = false })")
+  api.nvim_exec_autocmds('VimLeavePre', { modeline = false })
 end)
 
 describe('semantic token highlighting', function()
@@ -37,6 +39,8 @@ describe('semantic token highlighting', function()
       [7] = { bold = true, foreground = Screen.colors.DarkCyan },
       [8] = { bold = true, foreground = Screen.colors.SlateBlue },
       [9] = { bold = true, foreground = tonumber('0x6a0dad') },
+      [10] = { bold = true, foreground = Screen.colors.Brown },
+      [11] = { foreground = Screen.colors.Magenta1 },
     }
     command([[ hi link @lsp.type.namespace Type ]])
     command([[ hi link @lsp.type.function Special ]])
@@ -91,11 +95,11 @@ describe('semantic token highlighting', function()
             },
           },
           handlers = {
-            ['textDocument/semanticTokens/full'] = function()
-              return vim.fn.json_decode(response)
+            ['textDocument/semanticTokens/full'] = function(_, _, callback)
+              callback(nil, vim.fn.json_decode(response))
             end,
-            ['textDocument/semanticTokens/full/delta'] = function()
-              return vim.fn.json_decode(edit_response)
+            ['textDocument/semanticTokens/full/delta'] = function(_, _, callback)
+              callback(nil, vim.fn.json_decode(edit_response))
             end,
           }
         })
@@ -269,6 +273,63 @@ describe('semantic token highlighting', function()
       end
     )
 
+    it('highlights start and stop when using "0" for current buffer', function()
+      exec_lua([[
+        bufnr = vim.api.nvim_get_current_buf()
+        vim.api.nvim_win_set_buf(0, bufnr)
+        client_id = vim.lsp.start({ name = 'dummy', cmd = server.cmd })
+      ]])
+
+      insert(text)
+
+      exec_lua([[
+        vim.notify = function() end
+        vim.lsp.semantic_tokens.stop(0, client_id)
+      ]])
+
+      screen:expect {
+        grid = [[
+        #include <iostream>                     |
+                                                |
+        int main()                              |
+        {                                       |
+            int x;                              |
+        #ifdef __cplusplus                      |
+            std::cout << x << "\n";             |
+        #else                                   |
+            printf("%d\n", x);                  |
+        #endif                                  |
+        }                                       |
+        ^}                                       |
+        {1:~                                       }|*3
+                                                |
+      ]],
+      }
+
+      exec_lua([[
+        vim.lsp.semantic_tokens.start(0, client_id)
+      ]])
+
+      screen:expect {
+        grid = [[
+        #include <iostream>                     |
+                                                |
+        int {8:main}()                              |
+        {                                       |
+            int {7:x};                              |
+        #ifdef {5:__cplusplus}                      |
+            {4:std}::{2:cout} << {2:x} << "\n";             |
+        {6:#else}                                   |
+        {6:    printf("%d\n", x);}                  |
+        {6:#endif}                                  |
+        }                                       |
+        ^}                                       |
+        {1:~                                       }|*3
+                                                |
+      ]],
+      }
+    end)
+
     it('buffer is re-highlighted when force refreshed', function()
       exec_lua([[
         bufnr = vim.api.nvim_get_current_buf()
@@ -499,11 +560,11 @@ describe('semantic token highlighting', function()
             },
           },
           handlers = {
-            ['textDocument/semanticTokens/full'] = function()
-              return nil
+            ['textDocument/semanticTokens/full'] = function(_, _, callback)
+              callback(nil, nil)
             end,
             ['textDocument/semanticTokens/full/delta'] = function()
-              return nil
+              callback(nil, nil)
             end,
           }
         })
@@ -547,11 +608,11 @@ describe('semantic token highlighting', function()
             },
           },
           handlers = {
-            ['textDocument/semanticTokens/full'] = function()
-              return vim.fn.json_decode(response)
+            ['textDocument/semanticTokens/full'] = function(_, _, callback)
+              callback(nil, vim.fn.json_decode(response))
             end,
-            ['textDocument/semanticTokens/full/delta'] = function()
-              return vim.fn.json_decode(edit_response)
+            ['textDocument/semanticTokens/full/delta'] = function(_, _, callback)
+              callback(nil, vim.fn.json_decode(edit_response))
             end,
           }
         })
@@ -837,11 +898,13 @@ b = "as"]],
       {
         it = 'rust-analyzer',
         text = [[pub fn main() {
-  break rust;
-  /// what?
+    println!("Hello world!");
+    break rust;
+    /// what?
 }
 ]],
-        response = [[{"data": [0, 0, 3, 1, 0, 0, 4, 2, 1, 0, 0, 3, 4, 14, 524290, 0, 4, 1, 45, 0, 0, 1, 1, 45, 0, 0, 2, 1, 26, 0, 1, 4, 5, 1, 8192, 0, 6, 4, 52, 0, 0, 4, 1, 48, 0, 1, 4, 9, 0, 1, 1, 0, 1, 26, 0], "resultId": "1"}]],
+        response = [[{"data": [0, 0, 3, 1, 0, 0, 4, 2, 1, 0, 0, 3, 4, 14, 524290, 0, 4, 1, 45, 0, 0, 1, 1, 45, 0, 0, 2, 1, 26, 0, 1, 4, 8, 17, 0, 0, 8, 1, 45, 0, 0, 1, 14, 2, 0, 0, 14, 1, 45, 0, 0, 1, 1, 48, 0, 1, 4, 5, 1, 8192, 0, 6, 4, 52, 0, 0, 4, 1, 48, 0, 1, 4, 9, 0, 1, 1, 0, 1, 26, 0 ], "resultId": "1"}]],
+
         legend = [[{
         "tokenTypes": [
           "comment", "keyword", "string", "number", "regexp", "operator", "namespace", "type", "struct", "class", "interface", "enum", "enumMember", "typeParameter", "function", "method", "property", "macro", "variable",
@@ -904,6 +967,46 @@ b = "as"]],
           },
           {
             line = 1,
+            modifiers = {},
+            start_col = 4,
+            end_col = 12,
+            type = 'macro', -- println!
+            marked = true,
+          },
+          {
+            line = 1,
+            modifiers = {},
+            start_col = 12,
+            end_col = 13,
+            type = 'parenthesis',
+            marked = true,
+          },
+          {
+            line = 1,
+            modifiers = {},
+            start_col = 13,
+            end_col = 27,
+            type = 'string', -- "Hello world!"
+            marked = true,
+          },
+          {
+            line = 1,
+            modifiers = {},
+            start_col = 27,
+            end_col = 28,
+            type = 'parenthesis',
+            marked = true,
+          },
+          {
+            line = 1,
+            modifiers = {},
+            start_col = 28,
+            end_col = 29,
+            type = 'semicolon',
+            marked = true,
+          },
+          {
+            line = 2,
             modifiers = { controlFlow = true },
             start_col = 4,
             end_col = 9, -- break
@@ -911,31 +1014,31 @@ b = "as"]],
             marked = true,
           },
           {
-            line = 1,
+            line = 2,
             modifiers = {},
             start_col = 10,
-            end_col = 13, -- rust
+            end_col = 14, -- rust
             type = 'unresolvedReference',
             marked = true,
           },
           {
-            line = 1,
+            line = 2,
             modifiers = {},
-            start_col = 13,
-            end_col = 13,
+            start_col = 14,
+            end_col = 15,
             type = 'semicolon',
             marked = true,
           },
           {
-            line = 2,
+            line = 3,
             modifiers = { documentation = true },
             start_col = 4,
-            end_col = 11,
+            end_col = 13,
             type = 'comment', -- /// what?
             marked = true,
           },
           {
-            line = 3,
+            line = 4,
             modifiers = {},
             start_col = 0,
             end_col = 1,
@@ -946,12 +1049,13 @@ b = "as"]],
         expected_screen = function()
           screen:expect {
             grid = [[
-            pub fn {8:main}() {                         |
-              break rust;                           |
-              //{6:/ what?}                             |
+            {10:pub} {10:fn} {8:main}() {                         |
+                {5:println!}({11:"Hello world!"});           |
+                {10:break} rust;                         |
+                {6:/// what?}                           |
             }                                       |
             ^                                        |
-            {1:~                                       }|*10
+            {1:~                                       }|*9
                                                     |
           ]],
           }
@@ -971,8 +1075,8 @@ b = "as"]],
               },
             },
             handlers = {
-              ['textDocument/semanticTokens/full'] = function()
-                return vim.fn.json_decode(resp)
+              ['textDocument/semanticTokens/full'] = function(_, _, callback)
+                callback(nil, vim.fn.json_decode(resp))
               end,
             }
           })
@@ -1357,11 +1461,11 @@ int main()
               },
             },
             handlers = {
-              ['textDocument/semanticTokens/full'] = function()
-                return vim.fn.json_decode(resp1)
+              ['textDocument/semanticTokens/full'] = function(_, _, callback)
+                callback(nil, vim.fn.json_decode(resp1))
               end,
-              ['textDocument/semanticTokens/full/delta'] = function()
-                return vim.fn.json_decode(resp2)
+              ['textDocument/semanticTokens/full/delta'] = function(_, _, callback)
+                callback(nil, vim.fn.json_decode(resp2))
               end,
             }
           })
diff --git a/test/functional/plugin/lsp/snippet_spec.lua b/test/functional/plugin/lsp/snippet_spec.lua
index ba8bc7fe04..e60c36cd23 100644
--- a/test/functional/plugin/lsp/snippet_spec.lua
+++ b/test/functional/plugin/lsp/snippet_spec.lua
@@ -1,13 +1,15 @@
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
 local snippet = require('vim.lsp._snippet_grammar')
 local type = snippet.NodeType
 
-local eq = helpers.eq
-local exec_lua = helpers.exec_lua
+local eq = t.eq
+local exec_lua = n.exec_lua
 
 describe('vim.lsp._snippet_grammar', function()
-  before_each(helpers.clear)
-  after_each(helpers.clear)
+  before_each(n.clear)
+  after_each(n.clear)
 
   local parse = function(...)
     local res = exec_lua('return require("vim.lsp._snippet_grammar").parse(...)', ...)
diff --git a/test/functional/plugin/lsp/helpers.lua b/test/functional/plugin/lsp/testutil.lua
index 97fa108500..3430a1e1a3 100644
--- a/test/functional/plugin/lsp/helpers.lua
+++ b/test/functional/plugin/lsp/testutil.lua
@@ -1,9 +1,10 @@
-local helpers = require('test.functional.helpers')(nil)
+local n = require('test.functional.testnvim')()
 
-local clear = helpers.clear
-local exec_lua = helpers.exec_lua
-local run = helpers.run
-local stop = helpers.stop
+local clear = n.clear
+local exec_lua = n.exec_lua
+local run = n.run
+local stop = n.stop
+local api = n.api
 local NIL = vim.NIL
 
 local M = {}
@@ -38,8 +39,7 @@ M.create_server_definition = [[
         })
         local handler = handlers[method]
         if handler then
-          local response, err = handler(method, params)
-          callback(err, response)
+          handler(method, params, callback)
         elseif method == 'initialize' then
           callback(nil, {
             capabilities = opts.capabilities or {}
@@ -105,6 +105,11 @@ local function fake_lsp_server_setup(test_name, timeout_ms, options, settings)
           uri = 'file://' .. vim.uv.cwd(),
           name = 'test_folder',
       }};
+      before_init = function(params, config)
+        vim.schedule(function()
+          vim.rpcrequest(1, "setup")
+        end)
+      end,
       on_init = function(client, result)
         TEST_RPC_CLIENT = client
         vim.rpcrequest(1, "init", result)
@@ -128,6 +133,18 @@ local function fake_lsp_server_setup(test_name, timeout_ms, options, settings)
   )
 end
 
+--- @class test.lsp.Config
+--- @field test_name string
+--- @field timeout_ms? integer
+--- @field options? table
+--- @field settings? table
+---
+--- @field on_setup? fun()
+--- @field on_init? fun(client: vim.lsp.Client, ...)
+--- @field on_handler? fun(...)
+--- @field on_exit? fun(code: integer, signal: integer)
+
+--- @param config test.lsp.Config
 function M.test_rpc_server(config)
   if config.test_name then
     M.clear_notrace()
@@ -158,8 +175,15 @@ function M.test_rpc_server(config)
       end
     end,
   })
+  --- @type integer, integer
   local code, signal
   local function on_request(method, args)
+    if method == 'setup' then
+      if config.on_setup then
+        config.on_setup()
+      end
+      return NIL
+    end
     if method == 'init' then
       if config.on_init then
         config.on_init(client, unpack(args))
@@ -180,14 +204,14 @@ function M.test_rpc_server(config)
     end
   end
   --  TODO specify timeout?
-  --  run(on_request, on_notify, config.on_setup, 1000)
-  run(on_request, on_notify, config.on_setup)
+  --  run(on_request, on_notify, nil, 1000)
+  run(on_request, on_notify, nil)
   if config.on_exit then
     config.on_exit(code, signal)
   end
   stop()
   if config.test_name then
-    exec_lua("vim.api.nvim_exec_autocmds('VimLeavePre', { modeline = false })")
+    api.nvim_exec_autocmds('VimLeavePre', { modeline = false })
   end
 end
 
diff --git a/test/functional/plugin/lsp/utils_spec.lua b/test/functional/plugin/lsp/utils_spec.lua
index bb9cdb8390..6c6dec0667 100644
--- a/test/functional/plugin/lsp/utils_spec.lua
+++ b/test/functional/plugin/lsp/utils_spec.lua
@@ -1,12 +1,13 @@
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
-local feed = helpers.feed
 
-local eq = helpers.eq
-local exec_lua = helpers.exec_lua
+local feed = n.feed
+local eq = t.eq
+local exec_lua = n.exec_lua
 
 describe('vim.lsp.util', function()
-  before_each(helpers.clear)
+  before_each(n.clear)
 
   describe('stylize_markdown', function()
     local stylize_markdown = function(content, opts)
@@ -142,7 +143,7 @@ describe('vim.lsp.util', function()
 
     local screen
     before_each(function()
-      helpers.clear()
+      n.clear()
       screen = Screen.new(80, 80)
       screen:attach()
       feed('79i<CR><Esc>') -- fill screen with empty lines
diff --git a/test/functional/plugin/lsp_spec.lua b/test/functional/plugin/lsp_spec.lua
index 4826153edb..c95a96baca 100644
--- a/test/functional/plugin/lsp_spec.lua
+++ b/test/functional/plugin/lsp_spec.lua
@@ -1,36 +1,38 @@
-local helpers = require('test.functional.helpers')(after_each)
-local lsp_helpers = require('test.functional.plugin.lsp.helpers')
-
-local assert_log = helpers.assert_log
-local buf_lines = helpers.buf_lines
-local clear = helpers.clear
-local command = helpers.command
-local dedent = helpers.dedent
-local exec_lua = helpers.exec_lua
-local eq = helpers.eq
-local eval = helpers.eval
-local matches = helpers.matches
-local pcall_err = helpers.pcall_err
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local t_lsp = require('test.functional.plugin.lsp.testutil')
+
+local assert_log = t.assert_log
+local buf_lines = n.buf_lines
+local clear = n.clear
+local command = n.command
+local dedent = t.dedent
+local exec_lua = n.exec_lua
+local eq = t.eq
+local eval = n.eval
+local matches = t.matches
+local pcall_err = t.pcall_err
 local pesc = vim.pesc
-local insert = helpers.insert
-local fn = helpers.fn
-local retry = helpers.retry
-local stop = helpers.stop
+local insert = n.insert
+local fn = n.fn
+local retry = t.retry
+local stop = n.stop
 local NIL = vim.NIL
-local read_file = require('test.helpers').read_file
-local write_file = require('test.helpers').write_file
-local is_ci = helpers.is_ci
-local api = helpers.api
-local is_os = helpers.is_os
-local skip = helpers.skip
-local mkdir = helpers.mkdir
-local tmpname = helpers.tmpname
-
-local clear_notrace = lsp_helpers.clear_notrace
-local create_server_definition = lsp_helpers.create_server_definition
-local fake_lsp_code = lsp_helpers.fake_lsp_code
-local fake_lsp_logfile = lsp_helpers.fake_lsp_logfile
-local test_rpc_server = lsp_helpers.test_rpc_server
+local read_file = t.read_file
+local write_file = t.write_file
+local is_ci = t.is_ci
+local api = n.api
+local is_os = t.is_os
+local skip = t.skip
+local mkdir = t.mkdir
+local tmpname = t.tmpname
+
+local clear_notrace = t_lsp.clear_notrace
+local create_server_definition = t_lsp.create_server_definition
+local fake_lsp_code = t_lsp.fake_lsp_code
+local fake_lsp_logfile = t_lsp.fake_lsp_logfile
+local test_rpc_server = t_lsp.test_rpc_server
 
 local function get_buf_option(name, bufnr)
   bufnr = bufnr or 'BUFFER'
@@ -83,7 +85,7 @@ describe('LSP', function()
   end)
 
   after_each(function()
-    exec_lua("vim.api.nvim_exec_autocmds('VimLeavePre', { modeline = false })")
+    api.nvim_exec_autocmds('VimLeavePre', { modeline = false })
     -- exec_lua("lsp.stop_all_clients(true)")
   end)
 
@@ -146,7 +148,7 @@ describe('LSP', function()
     after_each(function()
       stop()
       exec_lua('lsp.stop_client(lsp.get_clients(), true)')
-      exec_lua("vim.api.nvim_exec_autocmds('VimLeavePre', { modeline = false })")
+      api.nvim_exec_autocmds('VimLeavePre', { modeline = false })
     end)
 
     it('should run correctly', function()
@@ -249,7 +251,7 @@ describe('LSP', function()
       if is_ci() then
         pending('hangs the build on CI #14028, re-enable with freeze timeout #14204')
         return
-      elseif helpers.skip_fragile(pending) then
+      elseif t.skip_fragile(pending) then
         return
       end
       local expected_handlers = {
@@ -279,7 +281,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'finish', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_finish',
         on_setup = function()
@@ -312,7 +314,7 @@ describe('LSP', function()
     end)
 
     it('should fire autocommands on attach and detach', function()
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_init',
         on_setup = function()
@@ -349,7 +351,7 @@ describe('LSP', function()
     end)
 
     it('should set default options on attach', function()
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'set_defaults_all_capabilities',
         on_init = function(_client)
@@ -397,7 +399,7 @@ describe('LSP', function()
     end)
 
     it('should overwrite options set by ftplugins', function()
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'set_defaults_all_capabilities',
         on_init = function(_client)
@@ -437,7 +439,7 @@ describe('LSP', function()
     end)
 
     it('should not overwrite user-defined options', function()
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'set_defaults_all_capabilities',
         on_init = function(_client)
@@ -473,6 +475,12 @@ describe('LSP', function()
         local server = _create_server()
         local bufnr = vim.api.nvim_create_buf(false, true)
         vim.api.nvim_set_current_buf(bufnr)
+        local detach_called = false
+        vim.api.nvim_create_autocmd("LspDetach", {
+          callback = function()
+            detach_called = true
+          end
+        })
         local client_id = vim.lsp.start({ name = 'detach-dummy', cmd = server.cmd })
         assert(client_id, "lsp.start must return client_id")
         local client = vim.lsp.get_client_by_id(client_id)
@@ -484,11 +492,42 @@ describe('LSP', function()
           client_id = client_id,
           num_attached_before = num_attached_before,
           num_attached_after = num_attached_after,
+          detach_called = detach_called,
         }
       ]])
       eq(true, result ~= nil, 'exec_lua must return result')
       eq(1, result.num_attached_before)
       eq(0, result.num_attached_after)
+      eq(true, result.detach_called)
+    end)
+
+    it('should not re-attach buffer if it was deleted in on_init #28575', function()
+      clear()
+      exec_lua(create_server_definition)
+      exec_lua([[
+        local server = _create_server({
+          handlers = {
+            initialize = function(method, params, callback)
+              vim.schedule(function()
+                callback(nil, { capabilities = {} })
+              end)
+            end
+          }
+        })
+        local bufnr = vim.api.nvim_create_buf(false, true)
+        local on_init_called = false
+        local client_id = vim.lsp.start({
+          name = 'detach-dummy',
+          cmd = server.cmd,
+          on_init = function()
+            vim.api.nvim_buf_delete(bufnr, {})
+            on_init_called = true
+          end
+        })
+        vim.lsp.buf_attach_client(bufnr, client_id)
+        local ok = vim.wait(1000, function() return on_init_called end)
+        assert(ok, "on_init was not called")
+      ]])
     end)
 
     it('client should return settings via workspace/configuration handler', function()
@@ -508,7 +547,7 @@ describe('LSP', function()
         },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'check_workspace_configuration',
         on_init = function(_client)
@@ -598,7 +637,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'text_document_sync_save_bool',
         on_init = function(c)
@@ -641,11 +680,11 @@ describe('LSP', function()
         vim.lsp.stop_client(client_id)
         return server.messages
       ]])
-      eq(#messages, 4)
-      eq(messages[1].method, 'initialize')
-      eq(messages[2].method, 'initialized')
-      eq(messages[3].method, 'shutdown')
-      eq(messages[4].method, 'exit')
+      eq(4, #messages)
+      eq('initialize', messages[1].method)
+      eq('initialized', messages[2].method)
+      eq('shutdown', messages[3].method)
+      eq('exit', messages[4].method)
     end)
 
     it('BufWritePre sends willSave / willSaveWaitUntil, applies textEdits', function()
@@ -660,7 +699,7 @@ describe('LSP', function()
             }
           },
           handlers = {
-            ['textDocument/willSaveWaitUntil'] = function()
+            ['textDocument/willSaveWaitUntil'] = function(_, _, callback)
               local text_edit = {
                 range = {
                   start = { line = 0, character = 0 },
@@ -668,7 +707,7 @@ describe('LSP', function()
                 },
                 newText = 'Hello'
               }
-              return { text_edit, }
+              callback(nil, { text_edit, })
             end
           },
         })
@@ -692,7 +731,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server({
         test_name = 'text_document_save_did_open',
         on_init = function(c)
@@ -732,7 +771,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'text_document_sync_save_includeText',
         on_init = function(c)
@@ -808,14 +847,12 @@ describe('LSP', function()
               BUFFER = vim.api.nvim_get_current_buf()
               lsp.buf_attach_client(BUFFER, TEST_RPC_CLIENT_ID)
               vim.lsp.handlers['textDocument/typeDefinition'] = function() end
+              vim.cmd(BUFFER.."bwipeout")
             ]=])
         end,
         on_init = function(client)
           client.stop()
           exec_lua('vim.lsp.buf.type_definition()')
-          exec_lua [[
-            vim.api.nvim_command(BUFFER.."bwipeout")
-          ]]
         end,
         on_exit = function(code, signal)
           eq(0, code, 'exit code')
@@ -859,7 +896,7 @@ describe('LSP', function()
       local expected_handlers = {
         { NIL, {}, { method = 'finish', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'check_forward_request_cancelled',
         on_init = function(_client)
@@ -885,7 +922,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { { code = -32801 }, NIL, { method = 'error_code_test', bufnr = 1, client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'check_forward_content_modified',
         on_init = function(_client)
@@ -915,7 +952,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'slow_request', bufnr = 1, client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'check_pending_request_tracked',
         on_init = function(_client)
@@ -949,7 +986,7 @@ describe('LSP', function()
       local expected_handlers = {
         { NIL, {}, { method = 'finish', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'check_cancel_request_tracked',
         on_init = function(_client)
@@ -982,7 +1019,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'slow_request', bufnr = 1, client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'check_tracked_requests_cleared',
         on_init = function(_client)
@@ -1021,7 +1058,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'slow_request', bufnr = 1, client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'check_tracked_requests_cleared',
         on_init = function(_client)
@@ -1057,7 +1094,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'finish', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_finish',
         on_setup = function()
@@ -1067,12 +1104,10 @@ describe('LSP', function()
               "testing";
               "123";
             })
-          ]]
-          eq(1, exec_lua('return TEST_RPC_CLIENT_ID'))
-          eq(true, exec_lua('return lsp.buf_attach_client(BUFFER, TEST_RPC_CLIENT_ID)'))
-          eq(true, exec_lua('return lsp.buf_is_attached(BUFFER, TEST_RPC_CLIENT_ID)'))
-          exec_lua [[
-            vim.api.nvim_command(BUFFER.."bwipeout")
+            assert(TEST_RPC_CLIENT_ID == 1)
+            assert(lsp.buf_attach_client(BUFFER, TEST_RPC_CLIENT_ID))
+            assert(lsp.buf_is_attached(BUFFER, TEST_RPC_CLIENT_ID))
+            vim.cmd(BUFFER.."bwipeout")
           ]]
         end,
         on_init = function(_client)
@@ -1101,7 +1136,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open',
         on_setup = function()
@@ -1147,7 +1182,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open',
         on_setup = function()
@@ -1190,7 +1225,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open_and_change',
         on_setup = function()
@@ -1238,7 +1273,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open_and_change_noeol',
         on_setup = function()
@@ -1305,7 +1340,7 @@ describe('LSP', function()
         },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'inlay_hint',
         on_setup = function()
@@ -1332,7 +1367,7 @@ describe('LSP', function()
         on_handler = function(err, result, ctx)
           if ctx.method == 'start' then
             exec_lua [[
-              vim.lsp.inlay_hint.enable(BUFFER)
+              vim.lsp.inlay_hint.enable(true, { bufnr = BUFFER })
             ]]
           end
           if ctx.method == 'textDocument/inlayHint' then
@@ -1352,7 +1387,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open_and_change_incremental',
         options = {
@@ -1403,7 +1438,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open_and_change_incremental',
         options = {
@@ -1457,7 +1492,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open_and_change_incremental_editing',
         on_setup = function()
@@ -1485,7 +1520,7 @@ describe('LSP', function()
         end,
         on_handler = function(err, result, ctx)
           if ctx.method == 'start' then
-            helpers.command('normal! 1Go')
+            n.command('normal! 1Go')
             client.notify('finish')
           end
           eq(table.remove(expected_handlers), { err, result, ctx }, 'expected handler')
@@ -1502,7 +1537,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open_and_change_multi',
         on_setup = function()
@@ -1553,7 +1588,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_check_buffer_open_and_change_multi_and_close',
         on_setup = function()
@@ -1607,7 +1642,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'finish', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'invalid_header',
         on_setup = function() end,
@@ -1640,7 +1675,7 @@ describe('LSP', function()
         },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'decode_nil',
         on_setup = function()
@@ -1807,7 +1842,7 @@ describe('LSP', function()
         make_edit(1, 0, 2, 5, 'foobar'),
         make_edit(4, 0, 5, 0, 'barfoo'),
       }
-      eq(true, exec_lua('return vim.api.nvim_buf_set_mark(1, "a", 2, 1, {})'))
+      eq(true, api.nvim_buf_set_mark(1, 'a', 2, 1, {}))
       exec_lua('vim.lsp.util.apply_text_edits(...)', edits, 1, 'utf-16')
       eq({
         'First line of text',
@@ -1815,7 +1850,7 @@ describe('LSP', function()
         'Fourth line of text',
         'barfoo',
       }, buf_lines(1))
-      local mark = exec_lua('return vim.api.nvim_buf_get_mark(1, "a")')
+      local mark = api.nvim_buf_get_mark(1, 'a')
       eq({ 2, 1 }, mark)
     end)
 
@@ -1824,7 +1859,7 @@ describe('LSP', function()
         make_edit(1, 0, 2, 15, 'foobar'),
         make_edit(4, 0, 5, 0, 'barfoo'),
       }
-      eq(true, exec_lua('return vim.api.nvim_buf_set_mark(1, "a", 2, 10, {})'))
+      eq(true, api.nvim_buf_set_mark(1, 'a', 2, 10, {}))
       exec_lua('vim.lsp.util.apply_text_edits(...)', edits, 1, 'utf-16')
       eq({
         'First line of text',
@@ -1832,7 +1867,7 @@ describe('LSP', function()
         'Fourth line of text',
         'barfoo',
       }, buf_lines(1))
-      local mark = exec_lua('return vim.api.nvim_buf_get_mark(1, "a")')
+      local mark = api.nvim_buf_get_mark(1, 'a')
       eq({ 2, 9 }, mark)
     end)
 
@@ -1841,19 +1876,19 @@ describe('LSP', function()
         make_edit(1, 0, 4, 5, 'foobar'),
         make_edit(4, 0, 5, 0, 'barfoo'),
       }
-      eq(true, exec_lua('return vim.api.nvim_buf_set_mark(1, "a", 4, 1, {})'))
+      eq(true, api.nvim_buf_set_mark(1, 'a', 4, 1, {}))
       exec_lua('vim.lsp.util.apply_text_edits(...)', edits, 1, 'utf-16')
       eq({
         'First line of text',
         'foobaro',
       }, buf_lines(1))
-      local mark = exec_lua('return vim.api.nvim_buf_get_mark(1, "a")')
+      local mark = api.nvim_buf_get_mark(1, 'a')
       eq({ 2, 1 }, mark)
     end)
 
     describe('cursor position', function()
       it("don't fix the cursor if the range contains the cursor", function()
-        fn.nvim_win_set_cursor(0, { 2, 6 })
+        api.nvim_win_set_cursor(0, { 2, 6 })
         local edits = {
           make_edit(1, 0, 1, 19, 'Second line of text'),
         }
@@ -1865,11 +1900,11 @@ describe('LSP', function()
           'Fourth line of text',
           'å å ɧ 汉语 ↥ 🤦 🦄',
         }, buf_lines(1))
-        eq({ 2, 6 }, fn.nvim_win_get_cursor(0))
+        eq({ 2, 6 }, api.nvim_win_get_cursor(0))
       end)
 
       it('fix the cursor to the valid col if the content was removed', function()
-        fn.nvim_win_set_cursor(0, { 2, 6 })
+        api.nvim_win_set_cursor(0, { 2, 6 })
         local edits = {
           make_edit(1, 0, 1, 6, ''),
           make_edit(1, 6, 1, 19, ''),
@@ -1882,11 +1917,11 @@ describe('LSP', function()
           'Fourth line of text',
           'å å ɧ 汉语 ↥ 🤦 🦄',
         }, buf_lines(1))
-        eq({ 2, 0 }, fn.nvim_win_get_cursor(0))
+        eq({ 2, 0 }, api.nvim_win_get_cursor(0))
       end)
 
       it('fix the cursor to the valid row if the content was removed', function()
-        fn.nvim_win_set_cursor(0, { 2, 6 })
+        api.nvim_win_set_cursor(0, { 2, 6 })
         local edits = {
           make_edit(1, 0, 1, 6, ''),
           make_edit(0, 18, 5, 0, ''),
@@ -1895,11 +1930,11 @@ describe('LSP', function()
         eq({
           'First line of text',
         }, buf_lines(1))
-        eq({ 1, 17 }, fn.nvim_win_get_cursor(0))
+        eq({ 1, 17 }, api.nvim_win_get_cursor(0))
       end)
 
       it('fix the cursor row', function()
-        fn.nvim_win_set_cursor(0, { 3, 0 })
+        api.nvim_win_set_cursor(0, { 3, 0 })
         local edits = {
           make_edit(1, 0, 2, 0, ''),
         }
@@ -1910,14 +1945,14 @@ describe('LSP', function()
           'Fourth line of text',
           'å å ɧ 汉语 ↥ 🤦 🦄',
         }, buf_lines(1))
-        eq({ 2, 0 }, fn.nvim_win_get_cursor(0))
+        eq({ 2, 0 }, api.nvim_win_get_cursor(0))
       end)
 
       it('fix the cursor col', function()
         -- append empty last line. See #22636
-        exec_lua('vim.api.nvim_buf_set_lines(...)', 1, -1, -1, true, { '' })
+        api.nvim_buf_set_lines(1, -1, -1, true, { '' })
 
-        fn.nvim_win_set_cursor(0, { 2, 11 })
+        api.nvim_win_set_cursor(0, { 2, 11 })
         local edits = {
           make_edit(1, 7, 1, 11, ''),
         }
@@ -1930,11 +1965,11 @@ describe('LSP', function()
           'å å ɧ 汉语 ↥ 🤦 🦄',
           '',
         }, buf_lines(1))
-        eq({ 2, 7 }, fn.nvim_win_get_cursor(0))
+        eq({ 2, 7 }, api.nvim_win_get_cursor(0))
       end)
 
       it('fix the cursor row and col', function()
-        fn.nvim_win_set_cursor(0, { 2, 12 })
+        api.nvim_win_set_cursor(0, { 2, 12 })
         local edits = {
           make_edit(0, 11, 1, 12, ''),
         }
@@ -1945,7 +1980,7 @@ describe('LSP', function()
           'Fourth line of text',
           'å å ɧ 汉语 ↥ 🤦 🦄',
         }, buf_lines(1))
-        eq({ 1, 11 }, fn.nvim_win_get_cursor(0))
+        eq({ 1, 11 }, api.nvim_win_get_cursor(0))
       end)
     end)
 
@@ -2021,7 +2056,7 @@ describe('LSP', function()
   end)
 
   describe('apply_text_document_edit', function()
-    local target_bufnr
+    local target_bufnr --- @type integer
     local text_document_edit = function(editVersion)
       return {
         edits = {
@@ -2267,7 +2302,7 @@ describe('LSP', function()
         },
       }
       exec_lua('vim.lsp.util.apply_workspace_edit(...)', edit, 'utf-16')
-      eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', tmpfile))
+      eq(true, vim.uv.fs_stat(tmpfile) ~= nil)
     end)
     it(
       'Supports file creation in folder that needs to be created with CreateFile payload',
@@ -2285,7 +2320,7 @@ describe('LSP', function()
           },
         }
         exec_lua('vim.lsp.util.apply_workspace_edit(...)', edit, 'utf-16')
-        eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', tmpfile))
+        eq(true, vim.uv.fs_stat(tmpfile) ~= nil)
       end
     )
     it('createFile does not touch file if it exists and ignoreIfExists is set', function()
@@ -2304,7 +2339,7 @@ describe('LSP', function()
         },
       }
       exec_lua('vim.lsp.util.apply_workspace_edit(...)', edit, 'utf-16')
-      eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', tmpfile))
+      eq(true, vim.uv.fs_stat(tmpfile) ~= nil)
       eq('Dummy content', read_file(tmpfile))
     end)
     it('createFile overrides file if overwrite is set', function()
@@ -2324,7 +2359,7 @@ describe('LSP', function()
         },
       }
       exec_lua('vim.lsp.util.apply_workspace_edit(...)', edit, 'utf-16')
-      eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', tmpfile))
+      eq(true, vim.uv.fs_stat(tmpfile) ~= nil)
       eq('', read_file(tmpfile))
     end)
     it('DeleteFile delete file and buffer', function()
@@ -2348,8 +2383,8 @@ describe('LSP', function()
         },
       }
       eq(true, pcall(exec_lua, 'vim.lsp.util.apply_workspace_edit(...)', edit, 'utf-16'))
-      eq(false, exec_lua('return vim.uv.fs_stat(...) ~= nil', tmpfile))
-      eq(false, exec_lua('return vim.api.nvim_buf_is_loaded(vim.fn.bufadd(...))', tmpfile))
+      eq(false, vim.uv.fs_stat(tmpfile) ~= nil)
+      eq(false, api.nvim_buf_is_loaded(fn.bufadd(tmpfile)))
     end)
     it('DeleteFile fails if file does not exist and ignoreIfNotExists is false', function()
       local tmpfile = tmpname()
@@ -2367,12 +2402,12 @@ describe('LSP', function()
         },
       }
       eq(false, pcall(exec_lua, 'vim.lsp.util.apply_workspace_edit(...)', edit))
-      eq(false, exec_lua('return vim.uv.fs_stat(...) ~= nil', tmpfile))
+      eq(false, vim.uv.fs_stat(tmpfile) ~= nil)
     end)
   end)
 
   describe('lsp.util.rename', function()
-    local pathsep = helpers.get_pathsep()
+    local pathsep = n.get_pathsep()
 
     it('Can rename an existing file', function()
       local old = tmpname()
@@ -2395,9 +2430,9 @@ describe('LSP', function()
         new
       )
       eq({ 'Test content' }, lines)
-      local exists = exec_lua('return vim.uv.fs_stat(...) ~= nil', old)
+      local exists = vim.uv.fs_stat(old) ~= nil
       eq(false, exists)
-      exists = exec_lua('return vim.uv.fs_stat(...) ~= nil', new)
+      exists = vim.uv.fs_stat(new) ~= nil
       eq(true, exists)
       os.remove(new)
     end)
@@ -2408,7 +2443,7 @@ describe('LSP', function()
       os.remove(old_dir)
       os.remove(new_dir)
 
-      helpers.mkdir_p(old_dir)
+      n.mkdir_p(old_dir)
 
       local file = 'file.txt'
       write_file(old_dir .. pathsep .. file, 'Test content')
@@ -2433,9 +2468,9 @@ describe('LSP', function()
         file
       )
       eq({ 'Test content' }, lines)
-      eq(false, exec_lua('return vim.uv.fs_stat(...) ~= nil', old_dir))
-      eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', new_dir))
-      eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', new_dir .. pathsep .. file))
+      eq(false, vim.uv.fs_stat(old_dir) ~= nil)
+      eq(true, vim.uv.fs_stat(new_dir) ~= nil)
+      eq(true, vim.uv.fs_stat(new_dir .. pathsep .. file) ~= nil)
 
       os.remove(new_dir)
     end)
@@ -2444,7 +2479,7 @@ describe('LSP', function()
       local new = tmpname()
       os.remove(old)
       os.remove(new)
-      helpers.mkdir_p(old)
+      n.mkdir_p(old)
 
       local result = exec_lua(
         [[
@@ -2499,7 +2534,7 @@ describe('LSP', function()
           new
         )
 
-        eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', old))
+        eq(true, vim.uv.fs_stat(old) ~= nil)
         eq('New file', read_file(new))
 
         exec_lua(
@@ -2513,7 +2548,7 @@ describe('LSP', function()
           new
         )
 
-        eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', old))
+        eq(true, vim.uv.fs_stat(old) ~= nil)
         eq('New file', read_file(new))
       end
     )
@@ -2543,8 +2578,8 @@ describe('LSP', function()
         old,
         new
       )
-      eq(false, exec_lua('return vim.uv.fs_stat(...) ~= nil', old))
-      eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', new))
+      eq(false, vim.uv.fs_stat(old) ~= nil)
+      eq(true, vim.uv.fs_stat(new) ~= nil)
       eq(true, undo_kept)
     end)
     it('Maintains undo information for unloaded buffer', function()
@@ -2570,8 +2605,8 @@ describe('LSP', function()
         old,
         new
       )
-      eq(false, exec_lua('return vim.uv.fs_stat(...) ~= nil', old))
-      eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', new))
+      eq(false, vim.uv.fs_stat(old) ~= nil)
+      eq(true, vim.uv.fs_stat(new) ~= nil)
       eq(true, undo_kept)
     end)
     it('Does not rename file when it conflicts with a buffer without file', function()
@@ -2615,8 +2650,8 @@ describe('LSP', function()
         new
       )
 
-      eq(false, exec_lua('return vim.uv.fs_stat(...) ~= nil', old))
-      eq(true, exec_lua('return vim.uv.fs_stat(...) ~= nil', new))
+      eq(false, vim.uv.fs_stat(old) ~= nil)
+      eq(true, vim.uv.fs_stat(new) ~= nil)
       eq('Old file', read_file(new))
     end)
   end)
@@ -2697,6 +2732,7 @@ describe('LSP', function()
       eq(expected, actual)
     end)
   end)
+
   describe('lsp.util.symbols_to_items', function()
     describe('convert DocumentSymbol[] to items', function()
       it('DocumentSymbol has children', function()
@@ -2971,7 +3007,7 @@ describe('LSP', function()
   end)
 
   describe('lsp.util.jump_to_location', function()
-    local target_bufnr
+    local target_bufnr --- @type integer
 
     before_each(function()
       target_bufnr = exec_lua [[
@@ -2994,10 +3030,10 @@ describe('LSP', function()
 
     local jump = function(msg)
       eq(true, exec_lua('return vim.lsp.util.jump_to_location(...)', msg, 'utf-16'))
-      eq(target_bufnr, exec_lua [[return vim.fn.bufnr('%')]])
+      eq(target_bufnr, fn.bufnr('%'))
       return {
-        line = exec_lua [[return vim.fn.line('.')]],
-        col = exec_lua [[return vim.fn.col('.')]],
+        line = fn.line('.'),
+        col = fn.col('.'),
       }
     end
 
@@ -3027,25 +3063,25 @@ describe('LSP', function()
       local pos = jump(location(1, 2, 1, 2))
       eq(2, pos.line)
       eq(4, pos.col)
-      eq('å', exec_lua [[return vim.fn.expand('<cword>')]])
+      eq('å', fn.expand('<cword>'))
     end)
 
     it('adds current position to jumplist before jumping', function()
-      fn.nvim_win_set_buf(0, target_bufnr)
-      local mark = fn.nvim_buf_get_mark(target_bufnr, "'")
+      api.nvim_win_set_buf(0, target_bufnr)
+      local mark = api.nvim_buf_get_mark(target_bufnr, "'")
       eq({ 1, 0 }, mark)
 
-      fn.nvim_win_set_cursor(0, { 2, 3 })
+      api.nvim_win_set_cursor(0, { 2, 3 })
       jump(location(0, 9, 0, 9))
 
-      mark = fn.nvim_buf_get_mark(target_bufnr, "'")
+      mark = api.nvim_buf_get_mark(target_bufnr, "'")
       eq({ 2, 3 }, mark)
     end)
   end)
 
   describe('lsp.util.show_document', function()
-    local target_bufnr
-    local target_bufnr2
+    local target_bufnr --- @type integer
+    local target_bufnr2 --- @type integer
 
     before_each(function()
       target_bufnr = exec_lua([[
@@ -3084,11 +3120,11 @@ describe('LSP', function()
         )
       )
       if focus == true or focus == nil then
-        eq(target_bufnr, exec_lua([[return vim.fn.bufnr('%')]]))
+        eq(target_bufnr, fn.bufnr('%'))
       end
       return {
-        line = exec_lua([[return vim.fn.line('.')]]),
-        col = exec_lua([[return vim.fn.col('.')]]),
+        line = fn.line('.'),
+        col = fn.col('.'),
       }
     end
 
@@ -3132,101 +3168,101 @@ describe('LSP', function()
     end)
 
     it('does not add current position to jumplist if not focus', function()
-      fn.nvim_win_set_buf(0, target_bufnr)
-      local mark = fn.nvim_buf_get_mark(target_bufnr, "'")
+      api.nvim_win_set_buf(0, target_bufnr)
+      local mark = api.nvim_buf_get_mark(target_bufnr, "'")
       eq({ 1, 0 }, mark)
 
-      fn.nvim_win_set_cursor(0, { 2, 3 })
+      api.nvim_win_set_cursor(0, { 2, 3 })
       show_document(location(0, 9, 0, 9), false, true)
       show_document(location(0, 9, 0, 9, true), false, true)
 
-      mark = fn.nvim_buf_get_mark(target_bufnr, "'")
+      mark = api.nvim_buf_get_mark(target_bufnr, "'")
       eq({ 1, 0 }, mark)
     end)
 
     it('does not change cursor position if not focus and not reuse_win', function()
-      fn.nvim_win_set_buf(0, target_bufnr)
-      local cursor = fn.nvim_win_get_cursor(0)
+      api.nvim_win_set_buf(0, target_bufnr)
+      local cursor = api.nvim_win_get_cursor(0)
 
       show_document(location(0, 9, 0, 9), false, false)
-      eq(cursor, fn.nvim_win_get_cursor(0))
+      eq(cursor, api.nvim_win_get_cursor(0))
     end)
 
     it('does not change window if not focus', function()
-      fn.nvim_win_set_buf(0, target_bufnr)
-      local win = fn.nvim_get_current_win()
+      api.nvim_win_set_buf(0, target_bufnr)
+      local win = api.nvim_get_current_win()
 
       -- same document/bufnr
       show_document(location(0, 9, 0, 9), false, true)
-      eq(win, fn.nvim_get_current_win())
+      eq(win, api.nvim_get_current_win())
 
       -- different document/bufnr, new window/split
       show_document(location(0, 9, 0, 9, true), false, true)
-      eq(2, #fn.nvim_list_wins())
-      eq(win, fn.nvim_get_current_win())
+      eq(2, #api.nvim_list_wins())
+      eq(win, api.nvim_get_current_win())
     end)
 
     it("respects 'reuse_win' parameter", function()
-      fn.nvim_win_set_buf(0, target_bufnr)
+      api.nvim_win_set_buf(0, target_bufnr)
 
       -- does not create a new window if the buffer is already open
       show_document(location(0, 9, 0, 9), false, true)
-      eq(1, #fn.nvim_list_wins())
+      eq(1, #api.nvim_list_wins())
 
       -- creates a new window even if the buffer is already open
       show_document(location(0, 9, 0, 9), false, false)
-      eq(2, #fn.nvim_list_wins())
+      eq(2, #api.nvim_list_wins())
     end)
 
     it('correctly sets the cursor of the split if range is given without focus', function()
-      fn.nvim_win_set_buf(0, target_bufnr)
+      api.nvim_win_set_buf(0, target_bufnr)
 
       show_document(location(0, 9, 0, 9, true), false, true)
 
-      local wins = fn.nvim_list_wins()
+      local wins = api.nvim_list_wins()
       eq(2, #wins)
       table.sort(wins)
 
-      eq({ 1, 0 }, fn.nvim_win_get_cursor(wins[1]))
-      eq({ 1, 9 }, fn.nvim_win_get_cursor(wins[2]))
+      eq({ 1, 0 }, api.nvim_win_get_cursor(wins[1]))
+      eq({ 1, 9 }, api.nvim_win_get_cursor(wins[2]))
     end)
 
     it('does not change cursor of the split if not range and not focus', function()
-      fn.nvim_win_set_buf(0, target_bufnr)
-      fn.nvim_win_set_cursor(0, { 2, 3 })
+      api.nvim_win_set_buf(0, target_bufnr)
+      api.nvim_win_set_cursor(0, { 2, 3 })
 
       exec_lua([[vim.cmd.new()]])
-      fn.nvim_win_set_buf(0, target_bufnr2)
-      fn.nvim_win_set_cursor(0, { 2, 3 })
+      api.nvim_win_set_buf(0, target_bufnr2)
+      api.nvim_win_set_cursor(0, { 2, 3 })
 
       show_document({ uri = 'file:///fake/uri2' }, false, true)
 
-      local wins = fn.nvim_list_wins()
+      local wins = api.nvim_list_wins()
       eq(2, #wins)
-      eq({ 2, 3 }, fn.nvim_win_get_cursor(wins[1]))
-      eq({ 2, 3 }, fn.nvim_win_get_cursor(wins[2]))
+      eq({ 2, 3 }, api.nvim_win_get_cursor(wins[1]))
+      eq({ 2, 3 }, api.nvim_win_get_cursor(wins[2]))
     end)
 
     it('respects existing buffers', function()
-      fn.nvim_win_set_buf(0, target_bufnr)
-      local win = fn.nvim_get_current_win()
+      api.nvim_win_set_buf(0, target_bufnr)
+      local win = api.nvim_get_current_win()
 
       exec_lua([[vim.cmd.new()]])
-      fn.nvim_win_set_buf(0, target_bufnr2)
-      fn.nvim_win_set_cursor(0, { 2, 3 })
-      local split = fn.nvim_get_current_win()
+      api.nvim_win_set_buf(0, target_bufnr2)
+      api.nvim_win_set_cursor(0, { 2, 3 })
+      local split = api.nvim_get_current_win()
 
       -- reuse win for open document/bufnr if called from split
       show_document(location(0, 9, 0, 9, true), false, true)
-      eq({ 1, 9 }, fn.nvim_win_get_cursor(split))
-      eq(2, #fn.nvim_list_wins())
+      eq({ 1, 9 }, api.nvim_win_get_cursor(split))
+      eq(2, #api.nvim_list_wins())
 
-      fn.nvim_set_current_win(win)
+      api.nvim_set_current_win(win)
 
       -- reuse win for open document/bufnr if called outside the split
       show_document(location(0, 9, 0, 9, true), false, true)
-      eq({ 1, 9 }, fn.nvim_win_get_cursor(split))
-      eq(2, #fn.nvim_list_wins())
+      eq({ 1, 9 }, api.nvim_win_get_cursor(split))
+      eq(2, #api.nvim_list_wins())
     end)
   end)
 
@@ -3464,6 +3500,442 @@ describe('LSP', function()
     end)
   end)
 
+  describe('vim.lsp.buf.typehierarchy subtypes', function()
+    it('does nothing for an empty response', function()
+      local qflist_count = exec_lua([=[
+        require'vim.lsp.handlers'['typeHierarchy/subtypes'](nil, nil, {})
+        return #vim.fn.getqflist()
+      ]=])
+      eq(0, qflist_count)
+    end)
+
+    it('opens the quickfix list with the right subtypes', function()
+      clear()
+      exec_lua(create_server_definition)
+      local qflist = exec_lua([=[
+        local clangd_response = { {
+          data = {
+            parents = { {
+              parents = { {
+                parents = { {
+                  parents = {},
+                  symbolID = "62B3D268A01B9978"
+                } },
+                symbolID = "DC9B0AD433B43BEC"
+              } },
+              symbolID = "06B5F6A19BA9F6A8"
+            } },
+            symbolID = "EDC336589C09ABB2"
+          },
+          kind = 5,
+          name = "D2",
+          range = {
+            ["end"] = {
+              character = 8,
+              line = 9
+            },
+            start = {
+              character = 6,
+              line = 9
+            }
+          },
+          selectionRange = {
+            ["end"] = {
+              character = 8,
+              line = 9
+            },
+            start = {
+              character = 6,
+              line = 9
+            }
+          },
+          uri = "file:///home/jiangyinzuo/hello.cpp"
+        }, {
+          data = {
+            parents = { {
+              parents = { {
+                parents = { {
+                  parents = {},
+                  symbolID = "62B3D268A01B9978"
+                } },
+                symbolID = "DC9B0AD433B43BEC"
+              } },
+              symbolID = "06B5F6A19BA9F6A8"
+            } },
+            symbolID = "AFFCAED15557EF08"
+          },
+          kind = 5,
+          name = "D1",
+          range = {
+            ["end"] = {
+              character = 8,
+              line = 8
+            },
+            start = {
+              character = 6,
+              line = 8
+            }
+          },
+          selectionRange = {
+            ["end"] = {
+              character = 8,
+              line = 8
+            },
+            start = {
+              character = 6,
+              line = 8
+            }
+          },
+          uri = "file:///home/jiangyinzuo/hello.cpp"
+        } }
+
+        local server = _create_server({
+          capabilities = {
+            positionEncoding = "utf-8"
+          },
+        })
+        local client_id = vim.lsp.start({ name = 'dummy', cmd = server.cmd })
+        local handler = require'vim.lsp.handlers'['typeHierarchy/subtypes']
+        handler(nil, clangd_response, { client_id = client_id, bufnr = 1 })
+        return vim.fn.getqflist()
+      ]=])
+
+      local expected = {
+        {
+          bufnr = 2,
+          col = 7,
+          end_col = 0,
+          end_lnum = 0,
+          lnum = 10,
+          module = '',
+          nr = 0,
+          pattern = '',
+          text = 'D2',
+          type = '',
+          valid = 1,
+          vcol = 0,
+        },
+        {
+          bufnr = 2,
+          col = 7,
+          end_col = 0,
+          end_lnum = 0,
+          lnum = 9,
+          module = '',
+          nr = 0,
+          pattern = '',
+          text = 'D1',
+          type = '',
+          valid = 1,
+          vcol = 0,
+        },
+      }
+
+      eq(expected, qflist)
+    end)
+
+    it('opens the quickfix list with the right subtypes and details', function()
+      clear()
+      exec_lua(create_server_definition)
+      local qflist = exec_lua([=[
+        local jdtls_response = {
+          {
+            data = { element = '=hello-java_ed323c3c/_<{Main.java[Main[A' },
+            detail = '',
+            kind = 5,
+            name = 'A',
+            range = {
+              ['end'] = { character = 26, line = 3 },
+              start = { character = 1, line = 3 },
+            },
+            selectionRange = {
+              ['end'] = { character = 8, line = 3 },
+              start = { character = 7, line = 3 },
+            },
+            tags = {},
+            uri = 'file:///home/jiangyinzuo/hello-java/Main.java',
+          },
+          {
+            data = { element = '=hello-java_ed323c3c/_<mylist{MyList.java[MyList[Inner' },
+            detail = 'mylist',
+            kind = 5,
+            name = 'MyList$Inner',
+            range = {
+              ['end'] = { character = 37, line = 3 },
+              start = { character = 1, line = 3 },
+            },
+            selectionRange = {
+              ['end'] = { character = 19, line = 3 },
+              start = { character = 14, line = 3 },
+            },
+            tags = {},
+            uri = 'file:///home/jiangyinzuo/hello-java/mylist/MyList.java',
+          },
+        }
+
+        local server = _create_server({
+          capabilities = {
+            positionEncoding = "utf-8"
+          },
+        })
+        local client_id = vim.lsp.start({ name = 'dummy', cmd = server.cmd })
+        local handler = require'vim.lsp.handlers'['typeHierarchy/subtypes']
+        handler(nil, jdtls_response, { client_id = client_id, bufnr = 1 })
+        return vim.fn.getqflist()
+      ]=])
+
+      local expected = {
+        {
+          bufnr = 2,
+          col = 2,
+          end_col = 0,
+          end_lnum = 0,
+          lnum = 4,
+          module = '',
+          nr = 0,
+          pattern = '',
+          text = 'A',
+          type = '',
+          valid = 1,
+          vcol = 0,
+        },
+        {
+          bufnr = 3,
+          col = 2,
+          end_col = 0,
+          end_lnum = 0,
+          lnum = 4,
+          module = '',
+          nr = 0,
+          pattern = '',
+          text = 'MyList$Inner mylist',
+          type = '',
+          valid = 1,
+          vcol = 0,
+        },
+      }
+      eq(expected, qflist)
+    end)
+  end)
+
+  describe('vim.lsp.buf.typehierarchy supertypes', function()
+    it('does nothing for an empty response', function()
+      local qflist_count = exec_lua([=[
+        require'vim.lsp.handlers'['typeHierarchy/supertypes'](nil, nil, {})
+        return #vim.fn.getqflist()
+      ]=])
+      eq(0, qflist_count)
+    end)
+
+    it('opens the quickfix list with the right supertypes', function()
+      clear()
+      exec_lua(create_server_definition)
+      local qflist = exec_lua([=[
+        local clangd_response = { {
+          data = {
+            parents = { {
+              parents = { {
+                parents = { {
+                  parents = {},
+                  symbolID = "62B3D268A01B9978"
+                } },
+                symbolID = "DC9B0AD433B43BEC"
+              } },
+              symbolID = "06B5F6A19BA9F6A8"
+            } },
+            symbolID = "EDC336589C09ABB2"
+          },
+          kind = 5,
+          name = "D2",
+          range = {
+            ["end"] = {
+              character = 8,
+              line = 9
+            },
+            start = {
+              character = 6,
+              line = 9
+            }
+          },
+          selectionRange = {
+            ["end"] = {
+              character = 8,
+              line = 9
+            },
+            start = {
+              character = 6,
+              line = 9
+            }
+          },
+          uri = "file:///home/jiangyinzuo/hello.cpp"
+        }, {
+          data = {
+            parents = { {
+              parents = { {
+                parents = { {
+                  parents = {},
+                  symbolID = "62B3D268A01B9978"
+                } },
+                symbolID = "DC9B0AD433B43BEC"
+              } },
+              symbolID = "06B5F6A19BA9F6A8"
+            } },
+            symbolID = "AFFCAED15557EF08"
+          },
+          kind = 5,
+          name = "D1",
+          range = {
+            ["end"] = {
+              character = 8,
+              line = 8
+            },
+            start = {
+              character = 6,
+              line = 8
+            }
+          },
+          selectionRange = {
+            ["end"] = {
+              character = 8,
+              line = 8
+            },
+            start = {
+              character = 6,
+              line = 8
+            }
+          },
+          uri = "file:///home/jiangyinzuo/hello.cpp"
+        } }
+
+        local server = _create_server({
+          capabilities = {
+            positionEncoding = "utf-8"
+          },
+        })
+        local client_id = vim.lsp.start({ name = 'dummy', cmd = server.cmd })
+        local handler = require'vim.lsp.handlers'['typeHierarchy/supertypes']
+        handler(nil, clangd_response, { client_id = client_id, bufnr = 1 })
+        return vim.fn.getqflist()
+      ]=])
+
+      local expected = {
+        {
+          bufnr = 2,
+          col = 7,
+          end_col = 0,
+          end_lnum = 0,
+          lnum = 10,
+          module = '',
+          nr = 0,
+          pattern = '',
+          text = 'D2',
+          type = '',
+          valid = 1,
+          vcol = 0,
+        },
+        {
+          bufnr = 2,
+          col = 7,
+          end_col = 0,
+          end_lnum = 0,
+          lnum = 9,
+          module = '',
+          nr = 0,
+          pattern = '',
+          text = 'D1',
+          type = '',
+          valid = 1,
+          vcol = 0,
+        },
+      }
+
+      eq(expected, qflist)
+    end)
+
+    it('opens the quickfix list with the right supertypes and details', function()
+      clear()
+      exec_lua(create_server_definition)
+      local qflist = exec_lua([=[
+        local jdtls_response = {
+          {
+            data = { element = '=hello-java_ed323c3c/_<{Main.java[Main[A' },
+            detail = '',
+            kind = 5,
+            name = 'A',
+            range = {
+              ['end'] = { character = 26, line = 3 },
+              start = { character = 1, line = 3 },
+            },
+            selectionRange = {
+              ['end'] = { character = 8, line = 3 },
+              start = { character = 7, line = 3 },
+            },
+            tags = {},
+            uri = 'file:///home/jiangyinzuo/hello-java/Main.java',
+          },
+          {
+            data = { element = '=hello-java_ed323c3c/_<mylist{MyList.java[MyList[Inner' },
+            detail = 'mylist',
+            kind = 5,
+            name = 'MyList$Inner',
+            range = {
+              ['end'] = { character = 37, line = 3 },
+              start = { character = 1, line = 3 },
+            },
+            selectionRange = {
+              ['end'] = { character = 19, line = 3 },
+              start = { character = 14, line = 3 },
+            },
+            tags = {},
+            uri = 'file:///home/jiangyinzuo/hello-java/mylist/MyList.java',
+          },
+        }
+
+        local server = _create_server({
+          capabilities = {
+            positionEncoding = "utf-8"
+          },
+        })
+        local client_id = vim.lsp.start({ name = 'dummy', cmd = server.cmd })
+        local handler = require'vim.lsp.handlers'['typeHierarchy/supertypes']
+        handler(nil, jdtls_response, { client_id = client_id, bufnr = 1 })
+        return vim.fn.getqflist()
+      ]=])
+
+      local expected = {
+        {
+          bufnr = 2,
+          col = 2,
+          end_col = 0,
+          end_lnum = 0,
+          lnum = 4,
+          module = '',
+          nr = 0,
+          pattern = '',
+          text = 'A',
+          type = '',
+          valid = 1,
+          vcol = 0,
+        },
+        {
+          bufnr = 3,
+          col = 2,
+          end_col = 0,
+          end_lnum = 0,
+          lnum = 4,
+          module = '',
+          nr = 0,
+          pattern = '',
+          text = 'MyList$Inner mylist',
+          type = '',
+          valid = 1,
+          vcol = 0,
+        },
+      }
+      eq(expected, qflist)
+    end)
+  end)
+
   describe('vim.lsp.buf.rename', function()
     for _, test in ipairs({
       {
@@ -3504,7 +3976,7 @@ describe('LSP', function()
       },
     }) do
       it(test.it, function()
-        local client
+        local client --- @type vim.lsp.Client
         test_rpc_server {
           test_name = test.name,
           on_init = function(_client)
@@ -3554,7 +4026,7 @@ describe('LSP', function()
 
   describe('vim.lsp.buf.code_action', function()
     it('Calls client side command if available', function()
-      local client
+      local client --- @type vim.lsp.Client
       local expected_handlers = {
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
@@ -3592,7 +4064,7 @@ describe('LSP', function()
       }
     end)
     it('Calls workspace/executeCommand if no client side command', function()
-      local client
+      local client --- @type vim.lsp.Client
       local expected_handlers = {
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         {
@@ -3632,7 +4104,7 @@ describe('LSP', function()
       })
     end)
     it('Filters and automatically applies action if requested', function()
-      local client
+      local client --- @type vim.lsp.Client
       local expected_handlers = {
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
@@ -3701,8 +4173,8 @@ describe('LSP', function()
             }
           },
           handlers = {
-            ["textDocument/codeAction"] = function()
-              return {
+            ["textDocument/codeAction"] = function(_, _, callback)
+              callback(nil, {
                 {
                   title = "Code Action 1",
                   command = {
@@ -3710,10 +4182,10 @@ describe('LSP', function()
                     command = "command:1",
                   }
                 }
-              }
+              })
             end,
-            ["codeAction/resolve"] = function()
-              return nil, "resolve failed"
+            ["codeAction/resolve"] = function(_, _, callback)
+              callback("resolve failed", nil)
             end,
           }
         })
@@ -3732,6 +4204,7 @@ describe('LSP', function()
       eq('command:1', result[5].params.command)
     end)
   end)
+
   describe('vim.lsp.commands', function()
     it('Accepts only string keys', function()
       matches(
@@ -3746,9 +4219,10 @@ describe('LSP', function()
       )
     end)
   end)
+
   describe('vim.lsp.codelens', function()
     it('uses client commands', function()
-      local client
+      local client --- @type vim.lsp.Client
       local expected_handlers = {
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
@@ -3802,7 +4276,7 @@ describe('LSP', function()
     end)
 
     it('releases buffer refresh lock', function()
-      local client
+      local client --- @type vim.lsp.Client
       local expected_handlers = {
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
@@ -3879,11 +4353,97 @@ describe('LSP', function()
         end,
       }
     end)
+
+    it('refresh multiple buffers', function()
+      local lens_title_per_fake_uri = {
+        ['file:///fake/uri1'] = 'Lens1',
+        ['file:///fake/uri2'] = 'Lens2',
+      }
+      clear()
+      exec_lua(create_server_definition)
+
+      -- setup lsp
+      exec_lua(
+        [[
+          local lens_title_per_fake_uri = ...
+          local server = _create_server({
+            capabilities = {
+              codeLensProvider = {
+                resolveProvider = true
+              },
+            },
+            handlers = {
+              ["textDocument/codeLens"] = function(method, params, callback)
+                local lenses = {
+                  {
+                    range = {
+                      start = { line = 0, character = 0 },
+                      ['end'] = { line = 0, character = 0 },
+                    },
+                    command = {
+                      title = lens_title_per_fake_uri[params.textDocument.uri],
+                      command = 'Dummy',
+                    },
+                  },
+                }
+                callback(nil, lenses)
+              end,
+            }
+          })
+
+          CLIENT_ID = vim.lsp.start({
+            name = "dummy",
+            cmd = server.cmd,
+          })
+        ]],
+        lens_title_per_fake_uri
+      )
+
+      -- create buffers and setup handler
+      exec_lua(
+        [[
+          local lens_title_per_fake_uri = ...
+          local default_buf = vim.api.nvim_get_current_buf()
+          for fake_uri, _ in pairs(lens_title_per_fake_uri) do
+            local bufnr = vim.uri_to_bufnr(fake_uri)
+            vim.api.nvim_set_current_buf(bufnr)
+            vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, {'Some contents'})
+            vim.lsp.buf_attach_client(bufnr, CLIENT_ID)
+          end
+          vim.api.nvim_buf_delete(default_buf, {force = true})
+
+          REQUEST_COUNT = vim.tbl_count(lens_title_per_fake_uri)
+          RESPONSES = {}
+          local on_codelens = vim.lsp.codelens.on_codelens
+          vim.lsp.codelens.on_codelens = function (err, result, ctx, ...)
+            table.insert(RESPONSES, { err = err, result = result, ctx = ctx })
+            return on_codelens(err, result, ctx, ...)
+          end
+        ]],
+        lens_title_per_fake_uri
+      )
+
+      -- call codelens refresh
+      local cmds = exec_lua([[
+        RESPONSES = {}
+        vim.lsp.codelens.refresh()
+        vim.wait(100, function () return #RESPONSES >= REQUEST_COUNT end)
+
+        local cmds = {}
+        for _, resp in ipairs(RESPONSES) do
+          local uri = resp.ctx.params.textDocument.uri
+          cmds[uri] = resp.result[1].command
+        end
+        return cmds
+      ]])
+      eq({ command = 'Dummy', title = 'Lens1' }, cmds['file:///fake/uri1'])
+      eq({ command = 'Dummy', title = 'Lens2' }, cmds['file:///fake/uri2'])
+    end)
   end)
 
   describe('vim.lsp.buf.format', function()
     it('Aborts with notify if no client matches filter', function()
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_init',
         on_init = function(c)
@@ -3912,7 +4472,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_formatting',
         on_init = function(c)
@@ -3945,7 +4505,7 @@ describe('LSP', function()
         { NIL, {}, { method = 'shutdown', client_id = 1 } },
         { NIL, {}, { method = 'start', client_id = 1 } },
       }
-      local client
+      local client --- @type vim.lsp.Client
       test_rpc_server {
         test_name = 'basic_formatting',
         on_init = function(c)
@@ -4068,6 +4628,9 @@ describe('LSP', function()
         end
       ]])
       local fail_msg = '[LSP] Format request failed, no matching language servers.'
+      --- @param name string
+      --- @param formatting boolean
+      --- @param range_formatting boolean
       local function check_notify(name, formatting, range_formatting)
         local timeout_msg = '[LSP][' .. name .. '] timeout'
         exec_lua(
@@ -4131,13 +4694,13 @@ describe('LSP', function()
           },
           handlers = {
             ---@return lsp.Location[]
-            ['textDocument/definition'] = function()
-              return { _G.mock_locations[1] }
+            ['textDocument/definition'] = function(_, _, callback)
+              callback(nil, { _G.mock_locations[1] })
             end,
             ---@return lsp.WorkspaceSymbol[]
-            ['workspace/symbol'] = function(_, request)
+            ['workspace/symbol'] = function(_, request, callback)
               assert(request.query == 'foobar')
-              return {
+              callback(nil, {
                 {
                   name = 'foobar',
                   kind = 13, ---@type lsp.SymbolKind
@@ -4148,7 +4711,7 @@ describe('LSP', function()
                   kind = 12, ---@type lsp.SymbolKind
                   location = _G.mock_locations[2],
                 }
-              }
+              })
             end,
           },
         })
@@ -4221,10 +4784,10 @@ describe('LSP', function()
         server:shutdown()
         return vim.json.decode(init)
       ]]
-      eq(result.method, 'initialize')
+      eq('initialize', result.method)
     end)
-    it('can connect to lsp server via rpc.domain_socket_connect', function()
-      local tmpfile
+    it('can connect to lsp server via pipe or domain_socket', function()
+      local tmpfile --- @type string
       if is_os('win') then
         tmpfile = '\\\\.\\\\pipe\\pipe.test'
       else
@@ -4248,7 +4811,7 @@ describe('LSP', function()
                         client:close()
                 end))
         end)
-        vim.lsp.start({ name = "dummy", cmd = vim.lsp.rpc.domain_socket_connect(SOCK) })
+        vim.lsp.start({ name = "dummy", cmd = vim.lsp.rpc.connect(SOCK) })
         vim.wait(1000, function() return init ~= nil end)
         assert(init, "server must receive `initialize` request")
         server:close()
@@ -4257,7 +4820,7 @@ describe('LSP', function()
       ]],
         tmpfile
       )
-      eq(result.method, 'initialize')
+      eq('initialize', result.method)
     end)
   end)
 
@@ -4449,18 +5012,26 @@ describe('LSP', function()
         string.format('sends notifications when files change (watchfunc=%s)', watchfunc),
         function()
           if watchfunc == 'fswatch' then
+            skip(is_os('win'), 'not supported on windows')
+            skip(is_os('mac'), 'flaky test on mac')
             skip(
               not is_ci() and fn.executable('fswatch') == 0,
               'fswatch not installed and not on CI'
             )
-            skip(is_os('win'), 'not supported on windows')
-            skip(is_os('mac'), 'flaky')
           end
 
-          skip(
-            is_os('bsd'),
-            'kqueue only reports events on watched folder itself, not contained files #26110'
-          )
+          if watchfunc == 'watch' then
+            skip(is_os('mac'), 'flaky test on mac')
+            skip(
+              is_os('bsd'),
+              'Stopped working on bsd after 3ca967387c49c754561c3b11a574797504d40f38'
+            )
+          else
+            skip(
+              is_os('bsd'),
+              'kqueue only reports events on watched folder itself, not contained files #26110'
+            )
+          end
 
           local root_dir = tmpname()
           os.remove(root_dir)
@@ -4679,14 +5250,7 @@ describe('LSP', function()
       )
 
       local function watched_uri(fname)
-        return exec_lua(
-          [[
-            local root_dir, fname = ...
-            return vim.uri_from_fname(root_dir .. '/' .. fname)
-          ]],
-          root_dir,
-          fname
-        )
+        return vim.uri_from_fname(root_dir .. '/' .. fname)
       end
 
       eq(4, #result)
@@ -4792,13 +5356,7 @@ describe('LSP', function()
       )
 
       local function watched_uri(fname)
-        return exec_lua(
-          [[
-            local fname = ...
-            return vim.uri_from_fname('/dir/' .. fname)
-          ]],
-          fname
-        )
+        return vim.uri_from_fname('/dir/' .. fname)
       end
 
       eq(3, #result)
@@ -4923,30 +5481,21 @@ describe('LSP', function()
         root_dir
       )
 
-      local function watched_uri(fname)
-        return exec_lua(
-          [[
-            return vim.uri_from_fname(...)
-          ]],
-          fname
-        )
-      end
-
       eq(3, #result)
       eq('workspace/didChangeWatchedFiles', result[3].method)
       eq({
         changes = {
           {
             type = exec_lua([[return vim.lsp.protocol.FileChangeType.Created]]),
-            uri = watched_uri('file1'),
+            uri = vim.uri_from_fname('file1'),
           },
           {
             type = exec_lua([[return vim.lsp.protocol.FileChangeType.Changed]]),
-            uri = watched_uri('file1'),
+            uri = vim.uri_from_fname('file1'),
           },
           {
             type = exec_lua([[return vim.lsp.protocol.FileChangeType.Created]]),
-            uri = watched_uri('file2'),
+            uri = vim.uri_from_fname('file2'),
           },
         },
       }, result[3].params)
@@ -5009,7 +5558,7 @@ describe('LSP', function()
         )
       end
 
-      eq(true, check_registered(nil)) -- start{_client}() defaults to make_client_capabilities().
+      eq(is_os('mac') or is_os('win'), check_registered(nil)) -- start{_client}() defaults to make_client_capabilities().
       eq(false, check_registered(vim.empty_dict()))
       eq(
         false,
diff --git a/test/functional/plugin/man_spec.lua b/test/functional/plugin/man_spec.lua
index 5bfa566729..978178191c 100644
--- a/test/functional/plugin/man_spec.lua
+++ b/test/functional/plugin/man_spec.lua
@@ -1,17 +1,19 @@
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
-local command, rawfeed = helpers.command, helpers.rawfeed
-local clear = helpers.clear
-local exec_lua = helpers.exec_lua
-local fn = helpers.fn
-local nvim_prog = helpers.nvim_prog
-local matches = helpers.matches
-local write_file = helpers.write_file
-local tmpname = helpers.tmpname
-local eq = helpers.eq
+
+local command, feed = n.command, n.feed
+local clear = n.clear
+local exec_lua = n.exec_lua
+local fn = n.fn
+local nvim_prog = n.nvim_prog
+local matches = t.matches
+local write_file = t.write_file
+local tmpname = t.tmpname
+local eq = t.eq
 local pesc = vim.pesc
-local skip = helpers.skip
-local is_ci = helpers.is_ci
+local skip = t.skip
+local is_ci = t.is_ci
 
 -- Collects all names passed to find_path() after attempting ":Man foo".
 local function get_search_history(name)
@@ -44,7 +46,7 @@ describe(':Man', function()
   end)
 
   describe('man.lua: highlight_line()', function()
-    local screen
+    local screen --- @type test.functional.ui.screen
 
     before_each(function()
       command('syntax on')
@@ -64,7 +66,7 @@ describe(':Man', function()
     end)
 
     it('clears backspaces from text and adds highlights', function()
-      rawfeed(
+      feed(
         [[
         ithis i<C-v><C-h>is<C-v><C-h>s a<C-v><C-h>a test
         with _<C-v><C-h>o_<C-v><C-h>v_<C-v><C-h>e_<C-v><C-h>r_<C-v><C-h>s_<C-v><C-h>t_<C-v><C-h>r_<C-v><C-h>u_<C-v><C-h>c_<C-v><C-h>k text<ESC>]]
@@ -90,7 +92,7 @@ describe(':Man', function()
     end)
 
     it('clears escape sequences from text and adds highlights', function()
-      rawfeed(
+      feed(
         [[
         ithis <C-v><ESC>[1mis <C-v><ESC>[3ma <C-v><ESC>[4mtest<C-v><ESC>[0m
         <C-v><ESC>[4mwith<C-v><ESC>[24m <C-v><ESC>[4mescaped<C-v><ESC>[24m <C-v><ESC>[4mtext<C-v><ESC>[24m<ESC>]]
@@ -116,7 +118,7 @@ describe(':Man', function()
     end)
 
     it('highlights multibyte text', function()
-      rawfeed(
+      feed(
         [[
         ithis i<C-v><C-h>is<C-v><C-h>s あ<C-v><C-h>あ test
         with _<C-v><C-h>ö_<C-v><C-h>v_<C-v><C-h>e_<C-v><C-h>r_<C-v><C-h>s_<C-v><C-h>t_<C-v><C-h>r_<C-v><C-h>u_<C-v><C-h>̃_<C-v><C-h>c_<C-v><C-h>k te<C-v><ESC>[3mxt¶<C-v><ESC>[0m<ESC>]]
@@ -132,7 +134,7 @@ describe(':Man', function()
     end)
 
     it('highlights underscores based on context', function()
-      rawfeed(
+      feed(
         [[
         i_<C-v><C-h>_b<C-v><C-h>be<C-v><C-h>eg<C-v><C-h>gi<C-v><C-h>in<C-v><C-h>ns<C-v><C-h>s
         m<C-v><C-h>mi<C-v><C-h>id<C-v><C-h>d_<C-v><C-h>_d<C-v><C-h>dl<C-v><C-h>le<C-v><C-h>e
@@ -150,7 +152,7 @@ describe(':Man', function()
     end)
 
     it('highlights various bullet formats', function()
-      rawfeed([[
+      feed([[
         i· ·<C-v><C-h>·
         +<C-v><C-h>o
         +<C-v><C-h>+<C-v><C-h>o<C-v><C-h>o double<ESC>]])
@@ -166,7 +168,7 @@ describe(':Man', function()
     end)
 
     it('handles : characters in input', function()
-      rawfeed([[
+      feed([[
         i<C-v><C-[>[40m    0  <C-v><C-[>[41m    1  <C-v><C-[>[42m    2  <C-v><C-[>[43m    3
         <C-v><C-[>[44m    4  <C-v><C-[>[45m    5  <C-v><C-[>[46m    6  <C-v><C-[>[47m    7  <C-v><C-[>[100m    8  <C-v><C-[>[101m    9
         <C-v><C-[>[102m   10  <C-v><C-[>[103m   11  <C-v><C-[>[104m   12  <C-v><C-[>[105m   13  <C-v><C-[>[106m   14  <C-v><C-[>[107m   15
@@ -190,6 +192,7 @@ describe(':Man', function()
       '--headless',
       '+autocmd VimLeave * echo "quit works!!"',
       '+Man!',
+      '+tag ls',
       '+call nvim_input("q")',
     }
     matches('quit works!!', fn.system(args, { 'manpage contents' }))
diff --git a/test/functional/plugin/matchparen_spec.lua b/test/functional/plugin/matchparen_spec.lua
index 530afd16e4..ae718ac1bd 100644
--- a/test/functional/plugin/matchparen_spec.lua
+++ b/test/functional/plugin/matchparen_spec.lua
@@ -1,14 +1,15 @@
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
-local clear = helpers.clear
-local command = helpers.command
-local api = helpers.api
-local feed = helpers.feed
-local eq = helpers.eq
+local clear = n.clear
+local command = n.command
+local api = n.api
+local feed = n.feed
+local eq = t.eq
 
 describe('matchparen', function()
-  local screen
+  local screen --- @type test.functional.ui.screen
 
   before_each(function()
     clear { args = { '-u', 'NORC' } }
diff --git a/test/functional/plugin/msgpack_spec.lua b/test/functional/plugin/msgpack_spec.lua
index 8511e6c703..1d5d20ec02 100644
--- a/test/functional/plugin/msgpack_spec.lua
+++ b/test/functional/plugin/msgpack_spec.lua
@@ -1,11 +1,13 @@
-local helpers = require('test.functional.helpers')(after_each)
-local clear = helpers.clear
-local api = helpers.api
-local eq = helpers.eq
-local nvim_eval = helpers.eval
-local nvim_command = helpers.command
-local exc_exec = helpers.exc_exec
-local ok = helpers.ok
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear = n.clear
+local api = n.api
+local eq = t.eq
+local nvim_eval = n.eval
+local nvim_command = n.command
+local exc_exec = n.exc_exec
+local ok = t.ok
 local NIL = vim.NIL
 
 describe('autoload/msgpack.vim', function()
diff --git a/test/functional/plugin/shada_spec.lua b/test/functional/plugin/shada_spec.lua
index 1c20548321..1c2bcbd497 100644
--- a/test/functional/plugin/shada_spec.lua
+++ b/test/functional/plugin/shada_spec.lua
@@ -1,13 +1,15 @@
-local helpers = require('test.functional.helpers')(after_each)
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
-local clear = helpers.clear
+local t_shada = require('test.functional.shada.testutil')
+
+local clear = n.clear
 local eq, api, nvim_eval, nvim_command, exc_exec, fn, nvim_feed =
-  helpers.eq, helpers.api, helpers.eval, helpers.command, helpers.exc_exec, helpers.fn, helpers.feed
-local neq = helpers.neq
-local read_file = helpers.read_file
+  t.eq, n.api, n.eval, n.command, n.exc_exec, n.fn, n.feed
+local neq = t.neq
+local read_file = t.read_file
 
-local shada_helpers = require('test.functional.shada.helpers')
-local get_shada_rw = shada_helpers.get_shada_rw
+local get_shada_rw = t_shada.get_shada_rw
 
 local function reset(shada_file)
   clear { args = { '-u', 'NORC', '-i', shada_file or 'NONE' } }
@@ -2612,7 +2614,7 @@ end)
 
 describe('plugin/shada.vim', function()
   local epoch = os.date('%Y-%m-%dT%H:%M:%S', 0)
-  local eol = helpers.is_os('win') and '\r\n' or '\n'
+  local eol = t.is_os('win') and '\r\n' or '\n'
   before_each(function()
     -- Note: reset() is called explicitly in each test.
     os.remove(fname)
diff --git a/test/functional/plugin/tohtml_spec.lua b/test/functional/plugin/tohtml_spec.lua
index 2ac0fe1fa3..200a5f34b2 100644
--- a/test/functional/plugin/tohtml_spec.lua
+++ b/test/functional/plugin/tohtml_spec.lua
@@ -1,13 +1,14 @@
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
-local helpers = require('test.functional.helpers')(after_each)
 
-local clear = helpers.clear
-local exec = helpers.exec
-local exec_lua = helpers.exec_lua
-local eq = helpers.eq
-local fn = helpers.fn
-local api = helpers.api
-local insert = helpers.insert
+local clear = n.clear
+local exec = n.exec
+local exec_lua = n.exec_lua
+local eq = t.eq
+local fn = n.fn
+local api = n.api
+local insert = n.insert
 
 local function html_syntax_match()
   local styles =
diff --git a/test/functional/plugin/tutor_spec.lua b/test/functional/plugin/tutor_spec.lua
index 99538e1db0..9f381d45db 100644
--- a/test/functional/plugin/tutor_spec.lua
+++ b/test/functional/plugin/tutor_spec.lua
@@ -1,18 +1,20 @@
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
-local helpers = require('test.functional.helpers')(after_each)
-local clear = helpers.clear
-local command = helpers.command
-local feed = helpers.feed
-local is_os = helpers.is_os
+
+local clear = n.clear
+local command = n.command
+local feed = n.feed
+local is_os = t.is_os
 
 describe(':Tutor', function()
-  local screen
+  local screen --- @type test.functional.ui.screen
 
   before_each(function()
     clear({ args = { '--clean' } })
     command('set cmdheight=0')
     command('Tutor')
-    screen = Screen.new(80, 30)
+    screen = Screen.new(81, 30)
     screen:set_default_attr_ids({
       [0] = { foreground = Screen.colors.DarkBlue, background = Screen.colors.Gray },
       [1] = { bold = true },
@@ -20,6 +22,7 @@ describe(':Tutor', function()
       [3] = { foreground = Screen.colors.SlateBlue },
       [4] = { bold = true, foreground = Screen.colors.Brown },
       [5] = { bold = true, foreground = Screen.colors.Magenta1 },
+      [6] = { italic = true },
     })
     screen:attach()
   end)
@@ -27,71 +30,109 @@ describe(':Tutor', function()
   it('applies {unix:…,win:…} transform', function()
     local expected = is_os('win')
         and [[
-      {0:  }^                                                                              |
-      {0:  } 3. To verify that a file was retrieved, cursor back and notice that there    |
-      {0:  }    are now two copies of Lesson 5.3, the original and the retrieved version. |
-      {0:  }                                                                              |
-      {0:  }{1:NOTE}: You can also read the output of an external command. For example,       |
-      {0:  }                                                                              |
-      {0:  }        :r {4:!}dir                                                               |
-      {0:  }                                                                              |
-      {0:  }      reads the output of the ls command and puts it below the cursor.        |
-      {0:  }                                                                              |
-      {0:  }{3:#}{5: Lesson 5 SUMMARY}                                                            |
-      {0:  }                                                                              |
-      {0:  } 1. {2::!command} executes an external command.                                   |
-      {0:  }                                                                              |
-      {0:  }     Some useful examples are:                                                |
-      {0:  }     :{4:!}dir                   - shows a directory listing                      |
-      {0:  }     :{4:!}del FILENAME          - removes file FILENAME                          |
-      {0:  }                                                                              |
-      {0:  } 2. {2::w} FILENAME              writes the current Neovim file to disk with      |
-      {0:  }                             name FILENAME.                                   |
-      {0:  }                                                                              |
-      {0:  } 3. {2:v}  motion  :w FILENAME   saves the Visually selected lines in file        |
-      {0:  }                             FILENAME.                                        |
-      {0:  }                                                                              |
-      {0:  } 4. {2::r} FILENAME              retrieves disk file FILENAME and puts it         |
-      {0:  }                             below the cursor position.                       |
-      {0:  }                                                                              |
-      {0:  } 5. {2::r !dir}                  reads the output of the dir command and          |
-      {0:  }                             puts it below the cursor position.               |
-      {0:  }                                                                              |
+      {0:  }^                                                                               |
+      {0:  } 3. To verify that a file was retrieved, cursor back and notice that there     |
+      {0:  }    are now two copies of Lesson 5.3, the original and the retrieved version.  |
+      {0:  }                                                                               |
+      {0:  }{1:NOTE}: You can also read the output of an external command. For example,        |
+      {0:  }                                                                               |
+      {0:  }        :r {4:!}dir                                                                |
+      {0:  }                                                                               |
+      {0:  }      reads the output of the ls command and puts it below the cursor.         |
+      {0:  }                                                                               |
+      {0:  }{3:#}{5: Lesson 5 SUMMARY}                                                             |
+      {0:  }                                                                               |
+      {0:  } 1. {2::!command} executes an external command.                                    |
+      {0:  }                                                                               |
+      {0:  }     Some useful examples are:                                                 |
+      {0:  }     :{4:!}dir                   - shows a directory listing                       |
+      {0:  }     :{4:!}del FILENAME          - removes file FILENAME                           |
+      {0:  }                                                                               |
+      {0:  } 2. {2::w} FILENAME              writes the current Neovim file to disk with       |
+      {0:  }                             name FILENAME.                                    |
+      {0:  }                                                                               |
+      {0:  } 3. {2:v}  motion  :w FILENAME   saves the Visually selected lines in file         |
+      {0:  }                             FILENAME.                                         |
+      {0:  }                                                                               |
+      {0:  } 4. {2::r} FILENAME              retrieves disk file FILENAME and puts it          |
+      {0:  }                             below the cursor position.                        |
+      {0:  }                                                                               |
+      {0:  } 5. {2::r !dir}                  reads the output of the dir command and           |
+      {0:  }                             puts it below the cursor position.                |
+      {0:  }                                                                               |
     ]]
       or [[
-      {0:  }^                                                                              |
-      {0:  } 3. To verify that a file was retrieved, cursor back and notice that there    |
-      {0:  }    are now two copies of Lesson 5.3, the original and the retrieved version. |
-      {0:  }                                                                              |
-      {0:  }{1:NOTE}: You can also read the output of an external command. For example,       |
-      {0:  }                                                                              |
-      {0:  }        :r {4:!}ls                                                                |
-      {0:  }                                                                              |
-      {0:  }      reads the output of the ls command and puts it below the cursor.        |
-      {0:  }                                                                              |
-      {0:  }{3:#}{5: Lesson 5 SUMMARY}                                                            |
-      {0:  }                                                                              |
-      {0:  } 1. {2::!command} executes an external command.                                   |
-      {0:  }                                                                              |
-      {0:  }     Some useful examples are:                                                |
-      {0:  }     :{4:!}ls                    - shows a directory listing                      |
-      {0:  }     :{4:!}rm  FILENAME          - removes file FILENAME                          |
-      {0:  }                                                                              |
-      {0:  } 2. {2::w} FILENAME              writes the current Neovim file to disk with      |
-      {0:  }                             name FILENAME.                                   |
-      {0:  }                                                                              |
-      {0:  } 3. {2:v}  motion  :w FILENAME   saves the Visually selected lines in file        |
-      {0:  }                             FILENAME.                                        |
-      {0:  }                                                                              |
-      {0:  } 4. {2::r} FILENAME              retrieves disk file FILENAME and puts it         |
-      {0:  }                             below the cursor position.                       |
-      {0:  }                                                                              |
-      {0:  } 5. {2::r !ls}                   reads the output of the ls command and           |
-      {0:  }                             puts it below the cursor position.               |
-      {0:  }                                                                              |
+      {0:  }^                                                                               |
+      {0:  } 3. To verify that a file was retrieved, cursor back and notice that there     |
+      {0:  }    are now two copies of Lesson 5.3, the original and the retrieved version.  |
+      {0:  }                                                                               |
+      {0:  }{1:NOTE}: You can also read the output of an external command. For example,        |
+      {0:  }                                                                               |
+      {0:  }        :r {4:!}ls                                                                 |
+      {0:  }                                                                               |
+      {0:  }      reads the output of the ls command and puts it below the cursor.         |
+      {0:  }                                                                               |
+      {0:  }{3:#}{5: Lesson 5 SUMMARY}                                                             |
+      {0:  }                                                                               |
+      {0:  } 1. {2::!command} executes an external command.                                    |
+      {0:  }                                                                               |
+      {0:  }     Some useful examples are:                                                 |
+      {0:  }     :{4:!}ls                    - shows a directory listing                       |
+      {0:  }     :{4:!}rm  FILENAME          - removes file FILENAME                           |
+      {0:  }                                                                               |
+      {0:  } 2. {2::w} FILENAME              writes the current Neovim file to disk with       |
+      {0:  }                             name FILENAME.                                    |
+      {0:  }                                                                               |
+      {0:  } 3. {2:v}  motion  :w FILENAME   saves the Visually selected lines in file         |
+      {0:  }                             FILENAME.                                         |
+      {0:  }                                                                               |
+      {0:  } 4. {2::r} FILENAME              retrieves disk file FILENAME and puts it          |
+      {0:  }                             below the cursor position.                        |
+      {0:  }                                                                               |
+      {0:  } 5. {2::r !ls}                   reads the output of the ls command and            |
+      {0:  }                             puts it below the cursor position.                |
+      {0:  }                                                                               |
     ]]
 
     feed(':700<CR>zt')
     screen:expect(expected)
   end)
+
+  it('applies hyperlink highlighting', function()
+    local expected = [[
+      {0:  }^                                                                               |
+      {0:  }{3:#}{5: CONCLUSION}                                                                   |
+      {0:  }                                                                               |
+      {0:  }This was intended to give a brief overview of the Neovim editor, just enough to|
+      {0:  }allow you to use it fairly easily. It is far from complete as Neovim has       |
+      {0:  }many many more commands. Consult the help often.                               |
+      {0:  }There are also countless great tutorials and videos to be found online.        |
+      {0:  }Here's a bunch of them:                                                        |
+      {0:  }                                                                               |
+      {0:  }- {6:Learn Vim Progressively}:                                                     |
+      {0:  }  {2:https://yannesposito.com/Scratch/en/blog/Learn-Vim-Progressively/}            |
+      {0:  }- {6:Learning Vim in 2014}:                                                        |
+      {0:  }  {2:https://benmccormick.org/learning-vim-in-2014/}                               |
+      {0:  }- {6:Vimcasts}:                                                                    |
+      {0:  }  {2:http://vimcasts.org/}                                                         |
+      {0:  }- {6:Vim Video-Tutorials by Derek Wyatt}:                                          |
+      {0:  }  {2:http://derekwyatt.org/vim/tutorials/}                                         |
+      {0:  }- {6:Learn Vimscript the Hard Way}:                                                |
+      {0:  }  {2:https://learnvimscriptthehardway.stevelosh.com/}                              |
+      {0:  }- {6:7 Habits of Effective Text Editing}:                                          |
+      {0:  }  {2:https://www.moolenaar.net/habits.html}                                        |
+      {0:  }- {6:vim-galore}:                                                                  |
+      {0:  }  {2:https://github.com/mhinz/vim-galore}                                          |
+      {0:  }                                                                               |
+      {0:  }If you prefer a book, {6:Practical Vim} by Drew Neil is recommended often          |
+      {0:  }(the sequel, {6:Modern Vim}, includes material specific to Neovim).                |
+      {0:  }                                                                               |
+      {0:  }This tutorial was written by Michael C. Pierce and Robert K. Ware, Colorado    |
+      {0:  }School of Mines using ideas supplied by Charles Smith, Colorado State          |
+      {0:  }University. E-mail: {2:bware@mines.colorado.edu}.                                  |
+    ]]
+
+    feed(':960<CR>zt')
+    screen:expect(expected)
+  end)
 end)
diff --git a/test/functional/plugin/vim_syntax_spec.lua b/test/functional/plugin/vim_syntax_spec.lua
index 9396bbce5c..d99a69eab9 100644
--- a/test/functional/plugin/vim_syntax_spec.lua
+++ b/test/functional/plugin/vim_syntax_spec.lua
@@ -1,15 +1,16 @@
-local helpers = require('test.functional.helpers')(after_each)
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
-local clear = helpers.clear
-local exec = helpers.exec
-local api = helpers.api
+
+local clear = n.clear
+local exec = n.exec
+local api = n.api
 
 describe('Vimscript syntax highlighting', function()
-  local screen
+  local screen --- @type test.functional.ui.screen
 
   before_each(function()
     clear()
-    helpers.add_builddir_to_rtp()
+    n.add_builddir_to_rtp()
     exec([[
       setfiletype vim
       syntax on