Merge pull request #953 from leapmotion/test-corethread

Extend unit tests for CoreThread behaviors

src/autowiring/BasicThread.cpp

@@ -130,8 +130,9 @@ bool BasicThread::OnStart(void) {
   m_running = true;
   m_wasStarted = true;
 
-  // Place the new thread entity directly in the space where it goes to avoid
-  // any kind of races arising from asynchronous access to this space
+  // Place the new thread entity directly in the space where it goes.  This
+  // enables us to decide in advance the exact location in memory where the
+  // object will be stored.
   auto outstanding = GetOutstanding();
   m_state->m_thisThread.~thread();
   new (&m_state->m_thisThread) std::thread(

src/autowiring/test/CoreThreadTest.cpp

@@ -622,22 +622,27 @@ TEST_F(CoreThreadTest, LambdaHoldAfterTermination) {
   ctxt->Initiate();
 
   std::weak_ptr<CoreContext> childWeak;
+  auto teardownCalled = std::make_shared<bool>(false);
+
   {
     AutoCreateContext child;
     AutoRequired<CoreThread> mct{ child };
 
     // This is the critical piece which generates a hold on `child` after teardown
-    mct->AddTeardownListener([mct, child] {
+    mct->AddTeardownListener([mct, child, teardownCalled] {
       *mct += [child] {};
+      *teardownCalled = true;
     });
 
     child->Initiate();
     *mct += [] {};
     mct->Barrier();
+    ASSERT_GE(1U, mct->GetDispatchQueueLength()) << "Dispatch queue had lingering entries after barrier";
     child->SignalShutdown();
     childWeak = child;
     child->Wait();
   }
+  ASSERT_TRUE(*teardownCalled) << "Teardown listener was not called as expected";
   ASSERT_TRUE(childWeak.expired()) << "Child context leaked due to lambda pending in teardown";
 }