test: improve test conventions

Work on https://github.com/neovim/neovim/issues/27004.

1 files changed, 219 insertions, 0 deletions

diff --git a/test/functional/plugin/lsp/testutil.lua b/test/functional/plugin/lsp/testutil.lua
new file mode 100644
index 0000000000..7dc7bd9925
--- /dev/null
+++ b/test/functional/plugin/lsp/testutil.lua
@@ -0,0 +1,219 @@
+local t = require('test.functional.testutil')(nil)
+
+local clear = t.clear
+local exec_lua = t.exec_lua
+local run = t.run
+local stop = t.stop
+local api = t.api
+local NIL = vim.NIL
+
+local M = {}
+
+function M.clear_notrace()
+  -- problem: here be dragons
+  -- solution: don't look too closely for dragons
+  clear {
+    env = {
+      NVIM_LUA_NOTRACK = '1',
+      NVIM_APPNAME = 'nvim_lsp_test',
+      VIMRUNTIME = os.getenv 'VIMRUNTIME',
+    },
+  }
+end
+
+M.create_server_definition = [[
+  function _create_server(opts)
+    opts = opts or {}
+    local server = {}
+    server.messages = {}
+
+    function server.cmd(dispatchers)
+      local closing = false
+      local handlers = opts.handlers or {}
+      local srv = {}
+
+      function srv.request(method, params, callback)
+        table.insert(server.messages, {
+          method = method,
+          params = params,
+        })
+        local handler = handlers[method]
+        if handler then
+          local response, err = handler(method, params)
+          callback(err, response)
+        elseif method == 'initialize' then
+          callback(nil, {
+            capabilities = opts.capabilities or {}
+          })
+        elseif method == 'shutdown' then
+          callback(nil, nil)
+        end
+        local request_id = #server.messages
+        return true, request_id
+      end
+
+      function srv.notify(method, params)
+        table.insert(server.messages, {
+          method = method,
+          params = params
+        })
+        if method == 'exit' then
+          dispatchers.on_exit(0, 15)
+        end
+      end
+
+      function srv.is_closing()
+        return closing
+      end
+
+      function srv.terminate()
+        closing = true
+      end
+
+      return srv
+    end
+
+    return server
+  end
+]]
+
+-- Fake LSP server.
+M.fake_lsp_code = 'test/functional/fixtures/fake-lsp-server.lua'
+M.fake_lsp_logfile = 'Xtest-fake-lsp.log'
+
+local function fake_lsp_server_setup(test_name, timeout_ms, options, settings)
+  exec_lua(
+    [=[
+    lsp = require('vim.lsp')
+    local test_name, fake_lsp_code, fake_lsp_logfile, timeout, options, settings = ...
+    TEST_RPC_CLIENT_ID = lsp.start_client {
+      cmd_env = {
+        NVIM_LOG_FILE = fake_lsp_logfile;
+        NVIM_LUA_NOTRACK = "1";
+        NVIM_APPNAME = "nvim_lsp_test";
+      };
+      cmd = {
+        vim.v.progpath, '-l', fake_lsp_code, test_name, tostring(timeout),
+      };
+      handlers = setmetatable({}, {
+        __index = function(t, method)
+          return function(...)
+            return vim.rpcrequest(1, 'handler', ...)
+          end
+        end;
+      });
+      workspace_folders = {{
+          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)
+      end;
+      flags = {
+        allow_incremental_sync = options.allow_incremental_sync or false;
+        debounce_text_changes = options.debounce_text_changes or 0;
+      };
+      settings = settings;
+      on_exit = function(...)
+        vim.rpcnotify(1, "exit", ...)
+      end;
+    }
+  ]=],
+    test_name,
+    M.fake_lsp_code,
+    M.fake_lsp_logfile,
+    timeout_ms or 1e3,
+    options or {},
+    settings or {}
+  )
+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()
+    fake_lsp_server_setup(
+      config.test_name,
+      config.timeout_ms or 1e3,
+      config.options,
+      config.settings
+    )
+  end
+  local client = setmetatable({}, {
+    __index = function(_, name)
+      -- Workaround for not being able to yield() inside __index for Lua 5.1 :(
+      -- Otherwise I would just return the value here.
+      return function(...)
+        return exec_lua(
+          [=[
+        local name = ...
+        if type(TEST_RPC_CLIENT[name]) == 'function' then
+          return TEST_RPC_CLIENT[name](select(2, ...))
+        else
+          return TEST_RPC_CLIENT[name]
+        end
+        ]=],
+          name,
+          ...
+        )
+      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))
+      end
+      return NIL
+    end
+    if method == 'handler' then
+      if config.on_handler then
+        config.on_handler(unpack(args))
+      end
+    end
+    return NIL
+  end
+  local function on_notify(method, args)
+    if method == 'exit' then
+      code, signal = unpack(args)
+      return stop()
+    end
+  end
+  --  TODO specify timeout?
+  --  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
+    api.nvim_exec_autocmds('VimLeavePre', { modeline = false })
+  end
+end
+
+return M