test: improve test conventions

Specifically, functions that are run in the context of the test runner
are put in module `test/testutil.lua` while the functions that are run
in the context of the test session are put in
`test/functional/testnvim.lua`.

Closes https://github.com/neovim/neovim/issues/27004.

44 files changed, 373 insertions, 305 deletions

diff --git a/test/functional/vimscript/api_functions_spec.lua b/test/functional/vimscript/api_functions_spec.lua
index bb10db8cd3..40d96ec281 100644
--- a/test/functional/vimscript/api_functions_spec.lua
+++ b/test/functional/vimscript/api_functions_spec.lua
@@ -1,13 +1,15 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
-local neq, eq, command = t.neq, t.eq, t.command
-local clear = t.clear
-local exc_exec, expect, eval = t.exc_exec, t.expect, t.eval
-local exec_lua = t.exec_lua
-local insert, pcall_err = t.insert, t.pcall_err
+
+local neq, eq, command = t.neq, t.eq, n.command
+local clear = n.clear
+local exc_exec, expect, eval = n.exc_exec, n.expect, n.eval
+local exec_lua = n.exec_lua
+local insert, pcall_err = n.insert, t.pcall_err
 local matches = t.matches
-local api = t.api
-local feed = t.feed
+local api = n.api
+local feed = n.feed
 
 describe('eval-API', function()
   before_each(clear)
diff --git a/test/functional/vimscript/buf_functions_spec.lua b/test/functional/vimscript/buf_functions_spec.lua
index 4889db0cb7..625fbe7e03 100644
--- a/test/functional/vimscript/buf_functions_spec.lua
+++ b/test/functional/vimscript/buf_functions_spec.lua
@@ -1,13 +1,14 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
 local eq = t.eq
-local clear = t.clear
-local fn = t.fn
-local api = t.api
-local command = t.command
-local exc_exec = t.exc_exec
-local get_pathsep = t.get_pathsep
-local rmdir = t.rmdir
+local clear = n.clear
+local fn = n.fn
+local api = n.api
+local command = n.command
+local exc_exec = n.exc_exec
+local get_pathsep = n.get_pathsep
+local rmdir = n.rmdir
 local pcall_err = t.pcall_err
 local mkdir = t.mkdir
 
diff --git a/test/functional/vimscript/changedtick_spec.lua b/test/functional/vimscript/changedtick_spec.lua
index ad8d42b4d5..baea53a700 100644
--- a/test/functional/vimscript/changedtick_spec.lua
+++ b/test/functional/vimscript/changedtick_spec.lua
@@ -1,15 +1,16 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
 local eq = t.eq
-local eval = t.eval
-local feed = t.feed
-local clear = t.clear
-local fn = t.fn
-local api = t.api
-local command = t.command
-local exc_exec = t.exc_exec
+local eval = n.eval
+local feed = n.feed
+local clear = n.clear
+local fn = n.fn
+local api = n.api
+local command = n.command
+local exc_exec = n.exc_exec
 local pcall_err = t.pcall_err
-local exec_capture = t.exec_capture
+local exec_capture = n.exec_capture
 
 before_each(clear)
 
diff --git a/test/functional/vimscript/container_functions_spec.lua b/test/functional/vimscript/container_functions_spec.lua
index a1bbee1e15..1d95bf6470 100644
--- a/test/functional/vimscript/container_functions_spec.lua
+++ b/test/functional/vimscript/container_functions_spec.lua
@@ -1,9 +1,10 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
 local eq = t.eq
-local eval = t.eval
-local api = t.api
-local clear = t.clear
+local eval = n.eval
+local api = n.api
+local clear = n.clear
 
 before_each(clear)
 
diff --git a/test/functional/vimscript/ctx_functions_spec.lua b/test/functional/vimscript/ctx_functions_spec.lua
index 956abe12e6..5e9a803b5d 100644
--- a/test/functional/vimscript/ctx_functions_spec.lua
+++ b/test/functional/vimscript/ctx_functions_spec.lua
@@ -1,16 +1,17 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local call = t.call
-local clear = t.clear
-local command = t.command
+local call = n.call
+local clear = n.clear
+local command = n.command
 local eq = t.eq
-local eval = t.eval
-local feed = t.feed
+local eval = n.eval
+local feed = n.feed
 local map = vim.tbl_map
-local api = t.api
-local parse_context = t.parse_context
-local exec_capture = t.exec_capture
-local source = t.source
+local api = n.api
+local parse_context = n.parse_context
+local exec_capture = n.exec_capture
+local source = n.source
 local trim = vim.trim
 local write_file = t.write_file
 local pcall_err = t.pcall_err
diff --git a/test/functional/vimscript/environ_spec.lua b/test/functional/vimscript/environ_spec.lua
index 9ef0edd815..abb093a6c8 100644
--- a/test/functional/vimscript/environ_spec.lua
+++ b/test/functional/vimscript/environ_spec.lua
@@ -1,13 +1,15 @@
-local t = require('test.functional.testutil')()
-local clear = t.clear
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear = n.clear
 local eq = t.eq
-local environ = t.fn.environ
-local exists = t.fn.exists
-local system = t.fn.system
-local nvim_prog = t.nvim_prog
-local command = t.command
-local eval = t.eval
-local setenv = t.fn.setenv
+local environ = n.fn.environ
+local exists = n.fn.exists
+local system = n.fn.system
+local nvim_prog = n.nvim_prog
+local command = n.command
+local eval = n.eval
+local setenv = n.fn.setenv
 
 describe('environment variables', function()
   it('environ() handles empty env variable', function()
diff --git a/test/functional/vimscript/errorlist_spec.lua b/test/functional/vimscript/errorlist_spec.lua
index 4e473b9e44..ef9111f788 100644
--- a/test/functional/vimscript/errorlist_spec.lua
+++ b/test/functional/vimscript/errorlist_spec.lua
@@ -1,13 +1,14 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local clear = t.clear
-local command = t.command
+local clear = n.clear
+local command = n.command
 local eq = t.eq
-local exc_exec = t.exc_exec
-local get_win_var = t.api.nvim_win_get_var
+local exc_exec = n.exc_exec
+local get_win_var = n.api.nvim_win_get_var
 
 describe('setqflist()', function()
-  local setqflist = t.fn.setqflist
+  local setqflist = n.fn.setqflist
 
   before_each(clear)
 
@@ -46,7 +47,7 @@ describe('setqflist()', function()
 end)
 
 describe('setloclist()', function()
-  local setloclist = t.fn.setloclist
+  local setloclist = n.fn.setloclist
 
   before_each(clear)
 
@@ -73,7 +74,7 @@ describe('setloclist()', function()
   end)
 
   it("doesn't crash when when window is closed in the middle #13721", function()
-    t.insert([[
+    n.insert([[
     hello world]])
 
     command('vsplit')
@@ -82,6 +83,6 @@ describe('setloclist()', function()
     command('call setloclist(0, [])')
     command('lopen')
 
-    t.assert_alive()
+    n.assert_alive()
   end)
 end)
diff --git a/test/functional/vimscript/eval_spec.lua b/test/functional/vimscript/eval_spec.lua
index b7c0803ef7..0c812d968e 100644
--- a/test/functional/vimscript/eval_spec.lua
+++ b/test/functional/vimscript/eval_spec.lua
@@ -9,37 +9,38 @@
 --    test/functional/vimscript/<funcname>_spec.lua
 --    test/functional/vimscript/functions_spec.lua
 
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
 local mkdir = t.mkdir
-local clear = t.clear
+local clear = n.clear
 local eq = t.eq
-local exec = t.exec
-local exc_exec = t.exc_exec
-local exec_lua = t.exec_lua
-local exec_capture = t.exec_capture
-local eval = t.eval
-local command = t.command
+local exec = n.exec
+local exc_exec = n.exc_exec
+local exec_lua = n.exec_lua
+local exec_capture = n.exec_capture
+local eval = n.eval
+local command = n.command
 local write_file = t.write_file
-local api = t.api
+local api = n.api
 local sleep = vim.uv.sleep
 local matches = t.matches
 local pcall_err = t.pcall_err
-local assert_alive = t.assert_alive
-local poke_eventloop = t.poke_eventloop
-local feed = t.feed
-local expect_exit = t.expect_exit
+local assert_alive = n.assert_alive
+local poke_eventloop = n.poke_eventloop
+local feed = n.feed
+local expect_exit = n.expect_exit
 
 describe('Up to MAX_FUNC_ARGS arguments are handled by', function()
   local max_func_args = 20 -- from eval.h
-  local range = t.fn.range
+  local range = n.fn.range
 
   before_each(clear)
 
   it('printf()', function()
-    local printf = t.fn.printf
-    local rep = t.fn['repeat']
+    local printf = n.fn.printf
+    local rep = n.fn['repeat']
     local expected = '2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,'
     eq(expected, printf(rep('%d,', max_func_args - 1), unpack(range(2, max_func_args))))
     local ret = exc_exec('call printf("", 2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21)')
@@ -47,7 +48,7 @@ describe('Up to MAX_FUNC_ARGS arguments are handled by', function()
   end)
 
   it('rpcnotify()', function()
-    local rpcnotify = t.fn.rpcnotify
+    local rpcnotify = n.fn.rpcnotify
     local ret = rpcnotify(0, 'foo', unpack(range(3, max_func_args)))
     eq(1, ret)
     ret = exc_exec('call rpcnotify(0, "foo", 3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21)')
@@ -69,7 +70,7 @@ describe('backtick expansion', function()
   end)
 
   teardown(function()
-    t.rmdir('test-backticks')
+    n.rmdir('test-backticks')
   end)
 
   it("with default 'shell'", function()
diff --git a/test/functional/vimscript/executable_spec.lua b/test/functional/vimscript/executable_spec.lua
index 75d36c26d9..e5530926c4 100644
--- a/test/functional/vimscript/executable_spec.lua
+++ b/test/functional/vimscript/executable_spec.lua
@@ -1,7 +1,9 @@
-local t = require('test.functional.testutil')()
-local eq, clear, call, write_file, command = t.eq, t.clear, t.call, t.write_file, t.command
-local exc_exec = t.exc_exec
-local eval = t.eval
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local eq, clear, call, write_file, command = t.eq, n.clear, n.call, t.write_file, n.command
+local exc_exec = n.exc_exec
+local eval = n.eval
 local is_os = t.is_os
 
 describe('executable()', function()
diff --git a/test/functional/vimscript/execute_spec.lua b/test/functional/vimscript/execute_spec.lua
index 32477323a1..8caaea39a7 100644
--- a/test/functional/vimscript/execute_spec.lua
+++ b/test/functional/vimscript/execute_spec.lua
@@ -1,14 +1,16 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+local Screen = require('test.functional.ui.screen')
+
 local eq = t.eq
-local eval = t.eval
-local clear = t.clear
-local source = t.source
-local exc_exec = t.exc_exec
+local eval = n.eval
+local clear = n.clear
+local source = n.source
+local exc_exec = n.exc_exec
 local pcall_err = t.pcall_err
-local fn = t.fn
-local Screen = require('test.functional.ui.screen')
-local command = t.command
-local feed = t.feed
+local fn = n.fn
+local command = n.command
+local feed = n.feed
 local is_os = t.is_os
 
 describe('execute()', function()
diff --git a/test/functional/vimscript/exepath_spec.lua b/test/functional/vimscript/exepath_spec.lua
index a1a2afb4ed..97747619ad 100644
--- a/test/functional/vimscript/exepath_spec.lua
+++ b/test/functional/vimscript/exepath_spec.lua
@@ -1,11 +1,13 @@
-local t = require('test.functional.testutil')()
-local eq, clear, call = t.eq, t.clear, t.call
-local command = t.command
-local exc_exec = t.exc_exec
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local eq, clear, call = t.eq, n.clear, n.call
+local command = n.command
+local exc_exec = n.exc_exec
 local matches = t.matches
 local is_os = t.is_os
-local set_shell_powershell = t.set_shell_powershell
-local eval = t.eval
+local set_shell_powershell = n.set_shell_powershell
+local eval = n.eval
 
 local find_dummies = function(ext_pat)
   local tmp_path = eval('$PATH')
diff --git a/test/functional/vimscript/fnamemodify_spec.lua b/test/functional/vimscript/fnamemodify_spec.lua
index fd2c79d9a5..51b1e8489a 100644
--- a/test/functional/vimscript/fnamemodify_spec.lua
+++ b/test/functional/vimscript/fnamemodify_spec.lua
@@ -1,11 +1,13 @@
-local t = require('test.functional.testutil')()
-local clear = t.clear
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear = n.clear
 local eq = t.eq
-local fnamemodify = t.fn.fnamemodify
-local getcwd = t.fn.getcwd
-local command = t.command
+local fnamemodify = n.fn.fnamemodify
+local getcwd = n.fn.getcwd
+local command = n.command
 local write_file = t.write_file
-local alter_slashes = t.alter_slashes
+local alter_slashes = n.alter_slashes
 local is_os = t.is_os
 
 local function eq_slashconvert(expected, got)
@@ -24,7 +26,7 @@ describe('fnamemodify()', function()
   end)
 
   it('handles the root path', function()
-    local root = t.pathroot()
+    local root = n.pathroot()
     eq(root, fnamemodify([[/]], ':p:h'))
     eq(root, fnamemodify([[/]], ':p'))
     if is_os('win') then
diff --git a/test/functional/vimscript/functions_spec.lua b/test/functional/vimscript/functions_spec.lua
index 1d57b60b95..7d9e80a32b 100644
--- a/test/functional/vimscript/functions_spec.lua
+++ b/test/functional/vimscript/functions_spec.lua
@@ -5,10 +5,11 @@
 --
 -- Core "eval" tests live in eval_spec.lua.
 
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local clear = t.clear
-local eval = t.eval
+local clear = n.clear
+local eval = n.eval
 local matches = t.matches
 local is_os = t.is_os
 
diff --git a/test/functional/vimscript/getline_spec.lua b/test/functional/vimscript/getline_spec.lua
index 18f7eabc25..32be6b5702 100644
--- a/test/functional/vimscript/getline_spec.lua
+++ b/test/functional/vimscript/getline_spec.lua
@@ -1,9 +1,10 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local call = t.call
-local clear = t.clear
+local call = n.call
+local clear = n.clear
 local eq = t.eq
-local expect = t.expect
+local expect = n.expect
 
 describe('getline()', function()
   before_each(function()
diff --git a/test/functional/vimscript/glob_spec.lua b/test/functional/vimscript/glob_spec.lua
index c66865611f..754381231e 100644
--- a/test/functional/vimscript/glob_spec.lua
+++ b/test/functional/vimscript/glob_spec.lua
@@ -1,5 +1,7 @@
-local t = require('test.functional.testutil')()
-local clear, command, eval, eq = t.clear, t.command, t.eval, t.eq
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear, command, eval, eq = n.clear, n.command, n.eval, t.eq
 local mkdir = t.mkdir
 
 before_each(function()
diff --git a/test/functional/vimscript/has_spec.lua b/test/functional/vimscript/has_spec.lua
index 05d5b04a29..1d2187be6b 100644
--- a/test/functional/vimscript/has_spec.lua
+++ b/test/functional/vimscript/has_spec.lua
@@ -1,11 +1,13 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
-local clear = t.clear
-local connect = t.connect
+
+local clear = n.clear
+local connect = n.connect
 local eq = t.eq
-local fn = t.fn
+local fn = n.fn
 local is_os = t.is_os
-local nvim_prog = t.nvim_prog
+local nvim_prog = n.nvim_prog
 
 describe('has()', function()
   before_each(clear)
diff --git a/test/functional/vimscript/hostname_spec.lua b/test/functional/vimscript/hostname_spec.lua
index e5be1cf4c3..e6b2499775 100644
--- a/test/functional/vimscript/hostname_spec.lua
+++ b/test/functional/vimscript/hostname_spec.lua
@@ -1,8 +1,10 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
 local eq = t.eq
 local ok = t.ok
-local call = t.call
-local clear = t.clear
+local call = n.call
+local clear = n.clear
 local is_os = t.is_os
 
 describe('hostname()', function()
diff --git a/test/functional/vimscript/input_spec.lua b/test/functional/vimscript/input_spec.lua
index e974d71356..552ae6d5cc 100644
--- a/test/functional/vimscript/input_spec.lua
+++ b/test/functional/vimscript/input_spec.lua
@@ -1,14 +1,15 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 local Screen = require('test.functional.ui.screen')
 
 local eq = t.eq
-local feed = t.feed
-local api = t.api
-local clear = t.clear
-local source = t.source
-local command = t.command
-local exc_exec = t.exc_exec
-local async_meths = t.async_meths
+local feed = n.feed
+local api = n.api
+local clear = n.clear
+local source = n.source
+local command = n.command
+local exc_exec = n.exc_exec
+local async_meths = n.async_meths
 local NIL = vim.NIL
 
 local screen
diff --git a/test/functional/vimscript/json_functions_spec.lua b/test/functional/vimscript/json_functions_spec.lua
index f17cf7017c..ae56e8873d 100644
--- a/test/functional/vimscript/json_functions_spec.lua
+++ b/test/functional/vimscript/json_functions_spec.lua
@@ -1,14 +1,16 @@
-local t = require('test.functional.testutil')()
-local clear = t.clear
-local fn = t.fn
-local api = t.api
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear = n.clear
+local fn = n.fn
+local api = n.api
 local eq = t.eq
-local eval = t.eval
-local command = t.command
-local exc_exec = t.exc_exec
+local eval = n.eval
+local command = n.command
+local exc_exec = n.exc_exec
 local pcall_err = t.pcall_err
 local NIL = vim.NIL
-local source = t.source
+local source = n.source
 
 describe('json_decode() function', function()
   local restart = function(...)
diff --git a/test/functional/vimscript/lang_spec.lua b/test/functional/vimscript/lang_spec.lua
index bb6b3ea5a7..923c8c215d 100644
--- a/test/functional/vimscript/lang_spec.lua
+++ b/test/functional/vimscript/lang_spec.lua
@@ -1,6 +1,8 @@
-local t = require('test.functional.testutil')()
-local clear, eval, eq = t.clear, t.eval, t.eq
-local exc_exec, source = t.exc_exec, t.source
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
+
+local clear, eval, eq = n.clear, n.eval, t.eq
+local exc_exec, source = n.exc_exec, n.source
 
 describe('vimscript', function()
   before_each(clear)
diff --git a/test/functional/vimscript/let_spec.lua b/test/functional/vimscript/let_spec.lua
index f8b9ba89d0..412e06df20 100644
--- a/test/functional/vimscript/let_spec.lua
+++ b/test/functional/vimscript/let_spec.lua
@@ -1,15 +1,16 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
 local eq = t.eq
-local clear = t.clear
-local command = t.command
-local eval = t.eval
-local api = t.api
-local exec = t.exec
-local exec_capture = t.exec_capture
-local expect_exit = t.expect_exit
-local source = t.source
-local testprg = t.testprg
+local clear = n.clear
+local command = n.command
+local eval = n.eval
+local api = n.api
+local exec = n.exec
+local exec_capture = n.exec_capture
+local expect_exit = n.expect_exit
+local source = n.source
+local testprg = n.testprg
 
 before_each(clear)
 
diff --git a/test/functional/vimscript/map_functions_spec.lua b/test/functional/vimscript/map_functions_spec.lua
index 249b79aa4e..44be5b3185 100644
--- a/test/functional/vimscript/map_functions_spec.lua
+++ b/test/functional/vimscript/map_functions_spec.lua
@@ -1,17 +1,18 @@
-local t = require('test.functional.testutil')()
+local t = require('test.testutil')
+local n = require('test.functional.testnvim')()
 
-local clear = t.clear
+local clear = n.clear
 local eq = t.eq
-local eval = t.eval
-local exec = t.exec
-local exec_lua = t.exec_lua
-local expect = t.expect
-local feed = t.feed
-local fn = t.fn
-local api = t.api
-local source = t.source
-local command = t.command
-local exec_capture = t.exec_capture
+local eval = n.eval
+local exec = n