Espresso: Wait for dialog to dismiss

Did you complete the Espresso Idling Resource quiz? Here comes the solution!

DialogFragmentIdlingResource

In the quiz, the test fails because we were verifying the text before the loading dialog dismisses. To make it pass, we can add an idling resource that is only idle when the dialog is not shown.

public DialogFragmentIdlingResource(
    FragmentManager manager, String tag) {
  this.manager = manager;
  this.tag = tag;
}

@Override
public boolean isIdleNow() {
  boolean idle = (manager.findFragmentByTag(tag) == null);
  if (idle) {
    resourceCallback.onTransitionToIdle();
  }
  return idle;
}

The idea is to query the FragmentManager with the tag of the loading dialog. If it is null, the DialogFragment is not there, and we consider the app idle.

Using the idling resource in test

@Test
public void done() {
  IdlingResource idlingResource = new DialogFragmentIdlingResource(
      activityRule.getActivity().getSupportFragmentManager(),
      LoadingDialogFragment.TAG);

  Espresso.registerIdlingResources(idlingResource);

  onView(withId(R.id.text))
      .check(matches(withText(R.string.done)));

  Espresso.unregisterIdlingResources(idlingResource);
}

We create an DialogFragmentIdlingResource with the tag from the loading dialog so that it knows what to wait for. With that, the test will wait until the loading dialog dismisses before proceeding. And now the test passes!

Source code

https://github.com/chiuki/espresso-samples/ under idling-resource-dialog-fragment on the solution branch.

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