    @Test
    public void getBunStream_emits_whenDataModelEmits() {

        ArrangeBuilder builder = new ArrangeBuilder();
        TestSubscriber<Bun> testSubscriber = new TestSubscriber<>();
        mViewModel.getBunStream().subscribe(testSubscriber);

        builder.withBun(BUN);

        testSubscriber.assertNoErrors();
        testSubscriber.assertValue(BUN);
    }