I have a UI test which clicks a button, and then launch a new Activity in its onClickListener. The test checks whether expected intent is sent or not.
My problem is, I want to test whether expected intent is sent without actually launching the activity. Because I found that new activity initializes its state, and it makes subsequent tests flaky.
I know there are two Espresso Intents API, which are intended and intending, but both fail to meet my needs. intended API actually launches the target activity, and intending API doesn't launch the activity, but it calls onActivityResult callback which I don't want either. Because I'm afraid that code inside onActivityResult may cause another flakiness.
Also intending doesn't assert whether matching intent is sent. It just calls onActivityResult callback when matching intent is found, which means I have to check whether onActivityResult is called or not!
Is there a clean way to achieve what I want?
Espresso's Intents class is a concise and handy api, but when it doesn't meet your needs, there is an alternative. If you use AndroidJUnit4 test runner, you can get Instrumentaion instance using InstrumentationRegistry.getInstrumentation(), and then you can add Instrumentation.ActivityMonitor instance.
Instrumentation.ActivityMonitor am = new Instrumentation.ActivityMonitor("YOUR_ACTIVITY", null, true);
InstrumentationRegistry.getInstrumentation().addMonitor(am);
onView(withId(R.id.view_id_to_perform_clicking)).check(matches(isDisplayed())).perform(click());
assertTrue(InstrumentationRegistry.getInstrumentation().checkMonitorHit(am, 1));
The third parameter of ActivityMonitor constructor tells we want to block activity launching. Note that this approach has its limitation. In contrast to Espresso Intents' rich Matcher support, You can not set multiple condition for ActivityMonitor.
You can find several samples in ApiDemos, especially in ContactsSelectInstrumentation class.