test: replace lfs with luv and vim.fs

test: replace lfs with luv

luv already pretty much does everything lfs does, so this duplication
of dependencies isn't needed.

test/functional/vimscript/api_functions_spec.lua

@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
-local lfs = require('lfs')
+local luv = require('luv')
 local neq, eq, command = helpers.neq, helpers.eq, helpers.command
 local clear, curbufmeths = helpers.clear, helpers.curbufmeths
 local exc_exec, expect, eval = helpers.exc_exec, helpers.expect, helpers.eval
@@ -118,7 +118,7 @@ describe('eval-API', function()
   end)
 
   it('are highlighted by vim.vim syntax file', function()
-    if lfs.attributes("build/runtime/syntax/vim/generated.vim",'uid') == nil then
+    if luv.fs_stat("build/runtime/syntax/vim/generated.vim").uid == nil then
       pending("runtime was not built, skipping test")
       return
     end

test/functional/vimscript/buf_functions_spec.lua

@@ -1,6 +1,6 @@
 local helpers = require('test.functional.helpers')(after_each)
 
-local lfs = require('lfs')
+local luv = require('luv')
 
 local eq = helpers.eq
 local clear = helpers.clear
@@ -16,6 +16,7 @@ local curtabmeths = helpers.curtabmeths
 local get_pathsep = helpers.get_pathsep
 local rmdir = helpers.rmdir
 local pcall_err = helpers.pcall_err
+local mkdir = helpers.mkdir
 
 local fname = 'Xtest-functional-eval-buf_functions'
 local fname2 = fname .. '.2'
@@ -62,7 +63,7 @@ describe('bufname() function', function()
     eq('', funcs.bufname('X'))
   end)
   before_each(function()
-    lfs.mkdir(dirname)
+    mkdir(dirname)
   end)
   after_each(function()
     rmdir(dirname)
@@ -70,7 +71,7 @@ describe('bufname() function', function()
   it('returns expected buffer name', function()
     eq('', funcs.bufname('%'))  -- Buffer has no name yet
     command('file ' .. fname)
-    local wd = lfs.currentdir()
+    local wd = luv.cwd()
     local sep = get_pathsep()
     local curdirname = funcs.fnamemodify(wd, ':t')
     for _, arg in ipairs({'%', 1, 'X', wd}) do
@@ -103,7 +104,7 @@ describe('bufnr() function', function()
   it('returns expected buffer number', function()
     eq(1, funcs.bufnr('%'))
     command('file ' .. fname)
-    local wd = lfs.currentdir()
+    local wd = luv.cwd()
     local curdirname = funcs.fnamemodify(wd, ':t')
     eq(1, funcs.bufnr(fname))
     eq(1, funcs.bufnr(wd))
@@ -144,7 +145,7 @@ describe('bufwinnr() function', function()
     eq(-1, funcs.bufwinnr('X'))
   end)
   before_each(function()
-    lfs.mkdir(dirname)
+    mkdir(dirname)
   end)
   after_each(function()
     rmdir(dirname)

test/functional/vimscript/eval_spec.lua

@@ -12,7 +12,7 @@
 local helpers = require('test.functional.helpers')(after_each)
 local Screen = require('test.functional.ui.screen')
 
-local lfs = require('lfs')
+local mkdir = helpers.mkdir
 local clear = helpers.clear
 local eq = helpers.eq
 local exc_exec = helpers.exc_exec
@@ -56,11 +56,11 @@ end)
 describe("backtick expansion", function()
   setup(function()
     clear()
-    lfs.mkdir("test-backticks")
+    mkdir("test-backticks")
     write_file("test-backticks/file1", "test file 1")
     write_file("test-backticks/file2", "test file 2")
     write_file("test-backticks/file3", "test file 3")
-    lfs.mkdir("test-backticks/subdir")
+    mkdir("test-backticks/subdir")
     write_file("test-backticks/subdir/file4", "test file 4")
     -- Long path might cause "Press ENTER" prompt; use :silent to avoid it.
     command('silent cd test-backticks')

test/functional/vimscript/glob_spec.lua

@@ -1,17 +1,18 @@
-local lfs = require('lfs')
+local luv = require('luv')
 local helpers = require('test.functional.helpers')(after_each)
 local clear, command, eval, eq = helpers.clear, helpers.command, helpers.eval, helpers.eq
+local mkdir = helpers.mkdir
 
 before_each(function()
   clear()
-  lfs.mkdir('test-glob')
+  mkdir('test-glob')
 
   -- Long path might cause "Press ENTER" prompt; use :silent to avoid it.
   command('silent cd test-glob')
 end)
 
 after_each(function()
-  lfs.rmdir('test-glob')
+  luv.fs_rmdir('test-glob')
 end)
 
 describe('glob()', function()

test/functional/vimscript/writefile_spec.lua

@@ -1,6 +1,7 @@
 local helpers = require('test.functional.helpers')(after_each)
-local lfs = require('lfs')
+local luv = require('luv')
 
+local mkdir = helpers.mkdir
 local clear = helpers.clear
 local eq = helpers.eq
 local funcs = helpers.funcs
@@ -19,16 +20,16 @@ local ddname_tail = '2'
 local ddname = dname .. '/' .. ddname_tail
 
 before_each(function()
-  lfs.mkdir(dname)
-  lfs.mkdir(ddname)
+  mkdir(dname)
+  mkdir(ddname)
   clear()
 end)
 
 after_each(function()
   os.remove(fname)
   os.remove(dfname)
-  lfs.rmdir(ddname)
-  lfs.rmdir(dname)
+  luv.fs_rmdir(ddname)
+  luv.fs_rmdir(dname)
 end)
 
 describe('writefile()', function()