An Espresso test

EspressoTest.java

@Test
public void testShowAlertDialog() throws Exception {
    	//act
	registrationActivity.showAlertDialog("No internet available.")
	ScreenShotter.takeScreenshot("details", activity);

    	//assert
	onView(withId(R.id.custom_alert_dialog_picture)).check(matches(isCompletelyDisplayed()));
	onView(withId(R.id.custom_alert_dialog_button)).check(matches(withText("Shucks")));
	onView(withId(R.id.custom_alert_dialog_button)).check(matches("No internet available."));
}