*: fix goroutine leak in ddl intergration test (#30369)

cmd/ddltest/ddl_serial_test.go

@@ -118,6 +118,11 @@ func createDDLSuite(t *testing.T) (s *ddlSuite) {
 	require.NoError(t, err)
 	ddl.RunWorker = false
 	session.ResetStoreForWithTiKVTest(s.store)
+	s.dom.Close()
+	require.NoError(t, s.store.Close())
+
+	s.store, err = store.New(fmt.Sprintf("tikv://%s%s", *etcd, *tikvPath))
+	require.NoError(t, err)
 	s.s, err = session.CreateSession(s.store)
 	require.NoError(t, err)
 	s.dom, err = session.BootstrapSession(s.store)
@@ -235,8 +240,14 @@ func (s *ddlSuite) stopServers() error {
 	defer s.m.Unlock()
 
 	for i := 0; i < len(s.procs); i++ {
-		if s.procs[i] != nil {
-			err := s.killServer(s.procs[i].Process)
+		if proc := s.procs[i]; proc != nil {
+			if proc.db != nil {
+				if err := proc.db.Close(); err != nil {
+					return err
+				}
+			}
+
+			err := s.killServer(proc.Process)
 			if err != nil {
 				return errors.Trace(err)
 			}

cmd/ddltest/main_test.go

@@ -32,5 +32,11 @@ func TestMain(m *testing.M) {
 		fmt.Fprint(os.Stderr, err.Error())
 		os.Exit(1)
 	}
-	goleak.VerifyTestMain(m)
+	opts := []goleak.Option{
+		goleak.IgnoreTopFunction("go.etcd.io/etcd/pkg/logutil.(*MergeLogger).outputLoop"),
+		goleak.IgnoreTopFunction("go.opencensus.io/stats/view.(*worker).start"),
+		goleak.IgnoreTopFunction("internal/poll.runtime_pollWait"),
+		goleak.IgnoreTopFunction("net/http.(*persistConn).writeLoop"),
+	}
+	goleak.VerifyTestMain(m, opts...)
 }