Fix some timing hole in these two testcases

tests/ut/cpp/dataset/connector_test.cc

@@ -55,6 +55,7 @@ private:
   uint32_t last_input_;
   uint32_t sleep_ms_ = 0;
   std::vector<uint32_t> input_;
+  WaitPost wp;
 
   // This worker loop is to be called by a single thread. It will pop my_conn Connector
   // and populate output vector
@@ -129,11 +130,13 @@ MindDataTestConnector::MindDataTestConnector() : tg_(new TaskGroup()) {
   for (int i = 1; i <= last_input_; i++) {
     input_.push_back(i);
   }
+  wp.Register(tg_.get());
 }
 
 Status MindDataTestConnector::Run_test_0() {
   Status rc;
   std::vector<uint32_t> output;
+  wp.Clear();
   auto my_conn = std::make_shared<Connector<uint32_t>>(1,  // num of producers
                                                       1,  // num of consumers
                                                       10);  // capacity of each queue
@@ -160,8 +163,11 @@ Status MindDataTestConnector::Run_test_0() {
                                       my_conn,
                                       &output));
   RETURN_IF_NOT_OK(rc);
-
-  tg_->join_all();
+  // Wait for the threads to finish.
+  rc = wp.Wait();
+  EXPECT_TRUE(rc.IsOk());
+  tg_->interrupt_all();
+  tg_->join_all(Task::WaitFlag::kNonBlocking);
   my_conn.reset();
   return ValidateOutput(output);
 }
@@ -169,6 +175,7 @@ Status MindDataTestConnector::Run_test_0() {
 Status MindDataTestConnector::Run_test_1() {
   std::vector<uint32_t> output;
   Status rc;
+  wp.Clear();
 
   // number of threads in each layer
   int l1_threads = 15;
@@ -223,8 +230,11 @@ Status MindDataTestConnector::Run_test_1() {
                                       conn2,  // poping the data from conn2
                                       &output));
   RETURN_IF_NOT_OK(rc);
-
-  tg_->join_all();
+  // Wait for the threads to finish.
+  rc = wp.Wait();
+  EXPECT_TRUE(rc.IsOk());
+  tg_->interrupt_all();
+  tg_->join_all(Task::WaitFlag::kNonBlocking);
   conn1.reset();
   conn2.reset();
 
@@ -250,11 +260,11 @@ Status MindDataTestConnector::SerialWorkerPull(
       GoToSleep(sleep_ms_);
     }
 
-    // Raising interrupt after it processed the last_input_.
+    // Signal master thread after it processed the last_input_.
     // This will trigger the MidWorkerJob threads to quit their worker loop.
     if (res == last_input_) {
       MS_LOG(INFO) << "All data is collected.";
-      tg_->interrupt_all();
+      wp.Set();
       break;
     }
   }

tests/ut/cpp/dataset/task_manager_test.cc

@@ -38,12 +38,13 @@ TEST_F(MindDataTestTaskManager, Test1) {
   ASSERT_TRUE(vg_rc.IsOk() || vg_rc.IsOutofMemory());
   ASSERT_TRUE(vg.join_all().IsOk());
   ASSERT_TRUE(vg.GetTaskErrorIfAny().IsOutofMemory());
-  // Test the error is passed back to the master thread.
+  // Test the error is passed back to the master thread if vg_rc above is OK.
+  // If vg_rc is kOutOfMemory, the group error is already passed back.
   // Some compiler may choose to run the next line in parallel with the above 3 lines
   // and this will cause some mismatch once a while.
   // To block this racing condition, we need to create a dependency that the next line
   // depends on previous lines.
-  if (vg.GetTaskErrorIfAny().IsError()) {
+  if (vg.GetTaskErrorIfAny().IsError() && vg_rc.IsOk()) {
     Status rc = TaskManager::GetMasterThreadRc();
     ASSERT_TRUE(rc.IsOutofMemory());
   }