Fix data race of data node test (#22221)

Signed-off-by: Naoiasd <zhicheng.yue@zilliz.com>

internal/datanode/data_node_test.go

@@ -111,6 +111,7 @@ func TestDataNode(t *testing.T) {
 	node.chunkManager = storage.NewLocalChunkManager(storage.RootPath("/tmp/milvus_test/datanode"))
 	paramtable.SetNodeID(1)
 
+	defer cancel()
 	t.Run("Test SetRootCoord", func(t *testing.T) {
 		emptyDN := &DataNode{}
 		tests := []struct {
@@ -196,19 +197,22 @@ func TestDataNode(t *testing.T) {
 		}{
 			{"fake-by-dev-rootcoord-dml-backgroundgc-1"},
 			{"fake-by-dev-rootcoord-dml-backgroundgc-2"},
-			{"fake-by-dev-rootcoord-dml-backgroundgc-3"},
-			{""},
-			{""},
 		}
 
-		for i, test := range testDataSyncs {
-			if i <= 2 {
-				err = node.flowgraphManager.addAndStart(node, &datapb.VchannelInfo{CollectionID: 1, ChannelName: test.dmChannelName}, nil, genTestTickler())
-				assert.Nil(t, err)
-				vchanNameCh <- test.dmChannelName
-			}
+		for _, test := range testDataSyncs {
+			err = node.flowgraphManager.addAndStart(node, &datapb.VchannelInfo{CollectionID: 1, ChannelName: test.dmChannelName}, nil, genTestTickler())
+			assert.Nil(t, err)
+			vchanNameCh <- test.dmChannelName
 		}
-		cancel()
+
+		assert.Eventually(t, func() bool {
+			for _, test := range testDataSyncs {
+				if node.flowgraphManager.exist(test.dmChannelName) {
+					return false
+				}
+			}
+			return true
+		}, 2*time.Second, 10*time.Millisecond)
 	})
 
 }