Tests: fix according to lualint

test/functional/api/server_requests_spec.lua

@@ -43,7 +43,7 @@ describe('server -> client', function()
         stop()
       end
 
-      local function on_request(method, args)
+      local function on_request()
         -- No need to evaluate the args, we are only interested in
         -- a response that contains an array with an empty string.
         return {1, 2, '', 3, 'asdf'}

test/functional/legacy/039_visual_block_mode_commands_spec.lua

@@ -5,7 +5,7 @@ local helpers = require('test.functional.helpers')
 local nvim, eq = helpers.meths, helpers.eq
 local insert, feed = helpers.insert, helpers.feed
 local clear, expect = helpers.clear, helpers.expect
-local source, execute = helpers.source, helpers.execute
+local execute = helpers.execute
 
 describe('Visual block mode', function()
 

test/functional/legacy/eval_spec.lua

@@ -3,7 +3,7 @@
 local helpers = require('test.functional.helpers')
 local feed, insert, source = helpers.feed, helpers.insert, helpers.source
 local clear, execute, expect = helpers.clear, helpers.execute, helpers.expect
-local eq, eval, wait, write_file = helpers.eq, helpers.eval, helpers.wait, helpers.write_file
+local eq, eval, write_file = helpers.eq, helpers.eval, helpers.write_file
 
 local function has_clipboard()
   clear()

test/functional/legacy/glob2regpat_spec.lua

@@ -1,7 +1,7 @@
 -- Tests for signs
 
 local helpers = require('test.functional.helpers')
-local clear, execute, expect = helpers.clear, helpers.execute, helpers.expect
+local clear, execute = helpers.clear, helpers.execute
 local eq, neq, eval = helpers.eq, helpers.neq, helpers.eval
 
 describe('glob2regpat()', function()

test/functional/legacy/quickfix_spec.lua

@@ -1,8 +1,7 @@
 -- Test for the quickfix commands.
 
 local helpers = require('test.functional.helpers')
-local insert, source = helpers.insert, helpers.source
-local clear, expect = helpers.clear, helpers.expect
+local source, clear = helpers.source, helpers.clear
 
 describe('helpgrep', function()
   before_each(clear)

test/unit/strings_spec.lua

@@ -1,7 +1,6 @@
 local helpers = require("test.unit.helpers")
 
 local cimport = helpers.cimport
-local internalize = helpers.internalize
 local eq = helpers.eq
 local ffi = helpers.ffi
 local to_cstr = helpers.to_cstr