test: use `T.TempDir` to create temporary test directory (#21043)

A testing cleanup. 

This pull request replaces `os.MkdirTemp` with `t.TempDir`. We can use the `T.TempDir` function from the `testing` package to create temporary directory. The directory created by `T.TempDir` is automatically removed when the test and all its subtests complete. 

This saves us at least 2 lines (error check, and cleanup) on every instance, or in some cases adds cleanup that we forgot.

Reference: https://pkg.go.dev/testing#T.TempDir

```go
func TestFoo(t *testing.T) {
	// before
	tmpDir, err := os.MkdirTemp("", "")
	require.NoError(t, err)
	defer os.RemoveAll(tmpDir)

	// now
	tmpDir := t.TempDir()
}
```

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

1 files changed, 1 insertions, 9 deletions

diff --git a/modules/indexer/code/bleve_test.go b/modules/indexer/code/bleve_test.go
index 37ed2eb9f0..a34d54bc0e 100644
--- a/modules/indexer/code/bleve_test.go
+++ b/modules/indexer/code/bleve_test.go
@@ -5,11 +5,9 @@
 package code
 
 import (
-	"os"
 	"testing"
 
 	"code.gitea.io/gitea/models/unittest"
-	"code.gitea.io/gitea/modules/util"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -17,13 +15,7 @@ import (
 func TestBleveIndexAndSearch(t *testing.T) {
 	unittest.PrepareTestEnv(t)
 
-	dir, err := os.MkdirTemp("", "bleve.index")
-	assert.NoError(t, err)
-	if err != nil {
-		assert.Fail(t, "Unable to create temporary directory")
-		return
-	}
-	defer util.RemoveAll(dir)
+	dir := t.TempDir()
 
 	idx, _, err := NewBleveIndexer(dir)
 	if err != nil {