Espresso: How do I test starting a new activity?

Question

If I have a MainActivity and a DetailActivity, how can I test that the DetailActivity has been launched?

public class MainScreenTest {

    @Rule
    public IntentsTestRule<MainActivity> mainActivityRule =
            new IntentsTestRule<>(MainActivity.class);

    @Test
    public void shouldOpenDetailActivityOnClick() {
        onView(withId(R.id.button)).check(matches(withText("Detail")));

        onView(withId(R.id.button))
                .perform(click());

        ...
    }

}

Answer 1

Here is one way of doing it:

public class MainScreenTest {

    @Rule
    public IntentsTestRule<MainActivity> mainActivityRule =
            new IntentsTestRule<>(MainActivity.class);

    @Test
    public void shouldOpenDetailActivityOnClick() {
        onView(withId(R.id.button)).check(matches(withText("Detail")));

        onView(withId(R.id.button))
                .perform(click());

        intended(hasComponent("com.example.androidplayground.DetailActivity"));
    }

}