@Test public void testClearBackStackImmediateOnEmptyStack() {

	// Arrange:
	final FragmentManager mockManager = mock(FragmentManager.class);
	final FragmentController controller = new FragmentController(mockManager);
	when(mockManager.getBackStackEntryCount()).thenReturn(0);
	// Act + Assert:
	assertThat(controller.clearBackStackImmediate(), is(false));
	verify(mockManager, times(2)).getBackStackEntryCount();
}