How to test android app has closed with Espresso

Question

How do I test if an Android application has closed after I click the native back button?

I can test if an activity has opened, but how do I test if a app has closed?

Answer 1

I'm guessing you might be able to do it through the Instrumentation class. The idea being, if you are not able to come back to the app from the last activity from which you exited, then the app is closed. I haven't tested it but perhaps you could do something like this:

Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
Instrumentation.ActivityMonitor activityMonitor = instrumentation.addMonitor(LastActivity.class.getName(), null, false);
Activity activity = instrumentation.waitForMonitorWithTimeout(activityMonitor, 1000);

Espresso.pressBack();

if(activity != null) {
  // do something
  fail();
}