discovery: use T.TempDir to create temporary test directory

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

discovery/message_store_test.go

@@ -2,9 +2,7 @@ package discovery
 
 import (
 	"bytes"
-	"io/ioutil"
 	"math/rand"
-	"os"
 	"reflect"
 	"testing"
 
@@ -16,29 +14,24 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func createTestMessageStore(t *testing.T) (*MessageStore, func()) {
+func createTestMessageStore(t *testing.T) *MessageStore {
 	t.Helper()
 
-	tempDir, err := ioutil.TempDir("", "channeldb")
-	require.NoError(t, err, "unable to create temp dir")
-	db, err := channeldb.Open(tempDir)
+	db, err := channeldb.Open(t.TempDir())
 	if err != nil {
-		os.RemoveAll(tempDir)
 		t.Fatalf("unable to open db: %v", err)
 	}
 
-	cleanUp := func() {
+	t.Cleanup(func() {
 		db.Close()
-		os.RemoveAll(tempDir)
-	}
+	})
 
 	store, err := NewMessageStore(db)
 	if err != nil {
-		cleanUp()
 		t.Fatalf("unable to initialize message store: %v", err)
 	}
 
-	return store, cleanUp
+	return store
 }
 
 func randPubKey(t *testing.T) *btcec.PublicKey {
@@ -79,8 +72,7 @@ func TestMessageStoreMessages(t *testing.T) {
 	t.Parallel()
 
 	// We'll start by creating our test message store.
-	msgStore, cleanUp := createTestMessageStore(t)
-	defer cleanUp()
+	msgStore := createTestMessageStore(t)
 
 	// We'll then create some test messages for two test peers, and none for
 	// an additional test peer.
@@ -212,8 +204,7 @@ func TestMessageStoreUnsupportedMessage(t *testing.T) {
 	t.Parallel()
 
 	// We'll start by creating our test message store.
-	msgStore, cleanUp := createTestMessageStore(t)
-	defer cleanUp()
+	msgStore := createTestMessageStore(t)
 
 	// Create a message that is known to not be supported by the store.
 	peer := randCompressedPubKey(t)
@@ -261,8 +252,7 @@ func TestMessageStoreUnsupportedMessage(t *testing.T) {
 func TestMessageStoreDeleteMessage(t *testing.T) {
 	t.Parallel()
 
-	msgStore, cleanUp := createTestMessageStore(t)
-	defer cleanUp()
+	msgStore := createTestMessageStore(t)
 
 	// assertMsg is a helper closure we'll use to ensure a message
 	// does/doesn't exist within the store.