all: use T.TempDir to create temporary test directory (#8280)

This commit replaces `os.MkdirTemp` with `t.TempDir` in tests. The
directory created by `t.TempDir` is automatically removed when the test
and all its subtests complete.

Prior to this commit, temporary directory created using `os.MkdirTemp`
needs to be removed manually by calling `os.RemoveAll`, which is omitted
in some tests. The error handling boilerplate e.g.
	defer func() {
		if err := os.RemoveAll(dir); err != nil {
			t.Fatal(err)
		}
	}
is also tedious, but `t.TempDir` handles this for us nicely.

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

lib/model/utils_test.go

@@ -7,7 +7,6 @@
 package model
 
 import (
-	"os"
 	"runtime"
 	"testing"
 
@@ -15,8 +14,7 @@ import (
 )
 
 func TestInWriteableDir(t *testing.T) {
-	dir := createTmpDir()
-	defer os.RemoveAll(dir)
+	dir := t.TempDir()
 
 	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
 
@@ -77,8 +75,7 @@ func TestOSWindowsRemove(t *testing.T) {
 		return
 	}
 
-	dir := createTmpDir()
-	defer os.RemoveAll(dir)
+	dir := t.TempDir()
 
 	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
 	defer fs.Chmod("testdata/windows/ro/readonlynew", 0700)
@@ -115,8 +112,7 @@ func TestOSWindowsRemoveAll(t *testing.T) {
 		return
 	}
 
-	dir := createTmpDir()
-	defer os.RemoveAll(dir)
+	dir := t.TempDir()
 
 	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
 	defer fs.Chmod("testdata/windows/ro/readonlynew", 0700)
@@ -148,8 +144,7 @@ func TestInWritableDirWindowsRename(t *testing.T) {
 		return
 	}
 
-	dir := createTmpDir()
-	defer os.RemoveAll(dir)
+	dir := t.TempDir()
 
 	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
 	defer fs.Chmod("testdata/windows/ro/readonlynew", 0700)