test: Ensure proper initialization in unit/helpers.lua

Remove helpers.vim_init and simply perform the required initialization in
helpers.lua.

test/unit/buffer_spec.lua

@@ -3,8 +3,6 @@ local helpers = require("test.unit.helpers")
 local to_cstr = helpers.to_cstr
 local eq      = helpers.eq
 
-helpers.vim_init()
-
 local buffer = helpers.cimport("./src/nvim/buffer.h")
 local window = helpers.cimport("./src/nvim/window.h")
 local option = helpers.cimport("./src/nvim/option.h")

test/unit/helpers.lua

@@ -136,15 +136,11 @@ end
 
 -- initialize some global variables, this is still necessary to unit test
 -- functions that rely on global state.
-local function vim_init()
-  if vim_init_called ~= nil then
-    return 
-  end
+do
   local main = cimport('./src/nvim/main.h')
   local time = cimport('./src/nvim/os/time.h')
   time.time_init()
   main.early_init()
-  vim_init_called = true
 end
 
 -- C constants.
@@ -167,7 +163,6 @@ return {
   lib = libnvim,
   cstr = cstr,
   to_cstr = to_cstr,
-  vim_init = vim_init,
   NULL = NULL,
   OK = OK,
   FAIL = FAIL

test/unit/os/env_spec.lua

@@ -12,9 +12,6 @@ local NULL = helpers.NULL
 
 require('lfs')
 
--- Needed because expand_env_esc uses the char table
-helpers.vim_init()
-
 local env = cimport('./src/nvim/os/os.h')
 
 describe('env function', function()

test/unit/tempfile_spec.lua

@@ -4,8 +4,6 @@ local helpers = require 'test.unit.helpers'
 local os = helpers.cimport './src/nvim/os/os.h'
 local tempfile = helpers.cimport './src/nvim/tempfile.h'
 
-helpers.vim_init()
-
 describe('tempfile related functions', function()
   after_each(function()
     tempfile.vim_deltempdir()