test: use T.TempDir to create temporary test directory

The directory created by `T.TempDir` is automatically removed when the
test and all its subtests complete.

Reference: https://pkg.go.dev/testing#T.TempDir
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

lib/file/file_test.go

@@ -13,15 +13,6 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-// Create a test directory then tidy up
-func testDir(t *testing.T) (string, func()) {
-	dir, err := ioutil.TempDir("", "rclone-test")
-	require.NoError(t, err)
-	return dir, func() {
-		assert.NoError(t, os.RemoveAll(dir))
-	}
-}
-
 // This lists dir and checks the listing is as expected without checking the size
 func checkListingNoSize(t *testing.T, dir string, want []string) {
 	var got []string
@@ -46,8 +37,7 @@ func checkListing(t *testing.T, dir string, want []string) {
 
 // Test we can rename an open file
 func TestOpenFileRename(t *testing.T) {
-	dir, tidy := testDir(t)
-	defer tidy()
+	dir := t.TempDir()
 
 	filepath := path.Join(dir, "file1")
 	f, err := Create(filepath)
@@ -71,8 +61,7 @@ func TestOpenFileRename(t *testing.T) {
 
 // Test we can delete an open file
 func TestOpenFileDelete(t *testing.T) {
-	dir, tidy := testDir(t)
-	defer tidy()
+	dir := t.TempDir()
 
 	filepath := path.Join(dir, "file1")
 	f, err := Create(filepath)
@@ -103,8 +92,7 @@ func TestOpenFileDelete(t *testing.T) {
 
 // Smoke test the Open, OpenFile and Create functions
 func TestOpenFileOperations(t *testing.T) {
-	dir, tidy := testDir(t)
-	defer tidy()
+	dir := t.TempDir()
 
 	filepath := path.Join(dir, "file1")
 

lib/file/mkdir_windows_test.go

@@ -15,8 +15,7 @@ import (
 
 // Basic test from golang's os/path_test.go
 func TestMkdirAll(t *testing.T) {
-	tmpDir, tidy := testDir(t)
-	defer tidy()
+	tmpDir := t.TempDir()
 
 	path := tmpDir + "/dir/./dir2"
 	err := MkdirAll(path, 0777)
@@ -99,8 +98,7 @@ func checkMkdirAllSubdirs(t *testing.T, path string, valid bool, errormsg string
 
 // Testing paths on existing drive
 func TestMkdirAllOnDrive(t *testing.T) {
-	path, tidy := testDir(t)
-	defer tidy()
+	path := t.TempDir()
 
 	dir, err := os.Stat(path)
 	require.NoError(t, err)