@Test public void incorrectFlowGetUsage() {

    Context mockContext = Mockito.mock(Context.class);
    //noinspection WrongConstant
    Mockito.when(mockContext.getSystemService(Mockito.anyString())).thenReturn(null);
    try {
        Flow.get(mockContext);
        fail("Flow was supposed to throw an exception on wrong usage");
    } catch (IllegalStateException ignored) {
        // That's good!
    }
}