CalledFromWrongThreadException exercising JUnit tests on Android

Question

I am new to JUnit and Android and good test documentation for working with Android is hard to find.

I have a test project with classes that extend ActivityInstrumentationTestCase2. Simple tests to examine the state of the GUI (what's enabled, relative positions, etc) work as expected. However when I attempt to perform button click actions, the wrong thread exception is thrown. Anyone know how to get around this issue?

As a follow-on, does anybody have any good suggestions for free resources on test or TDD for Android? I am using Eclipse/MotoDev.

Thanks

I can get different failure traces depending on how I invoke each button, but including one here for reference:

android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views. at android.view.ViewRoot.checkThread(ViewRoot.java:2683) at android.view.ViewRoot.playSoundEffect(ViewRoot.java:2472) at android.view.View.playSoundEffect(View.java:8307) at android.view.View.performClick(View.java:2363) at com.android.tigerslair.demo1.test.GoTest.setUp(GoTest.java:49) at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:169) at android.test.AndroidTestRunner.runTest(AndroidTestRunner.java:154) at android.test.InstrumentationTestRunner.onStart(InstrumentationTestRunner.java:430) at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:1447)

Here is the simple setup() routine:

@Override
protected void setUp() throws Exception {
    super.setUp();
    TigersLair activity=getActivity();

    mGoBtn = (Button) activity.findViewById(R.id.go);
    mGoBtn.performClick();        
}

It doesn't matter if I perform the click in setUp() or the actual test.

Answer 1

You need to execute all clicks in the UIThread.

This can be done by the following two examples.

@UiThreadTest
public void testApp() {
  TestApp activity = getActivity();

  Button mGoBtn = (Button) activity.findViewById(R.id.testbutton);
  mGoBtn.performClick();
}

or

public void testApp2() throws Throwable {
  TestApp activity = getActivity();

  final Button mGoBtn = (Button) activity.findViewById(R.id.testbutton);
  runTestOnUiThread(new Runnable() {

    @Override
    public void run() {
      mGoBtn.performClick();
    }
  });
}