RxJava: Flowable to Single

EmptyFlowableToSingle.java

	@Test
	public void testEmptyFlowableToSingle() {
		Flowable.empty()
				.flatMapSingle(o -> Single.just("result"))
				.test()
				.assertValueCount(0)
				.assertNoErrors();
		//There should have been an error
	}

FlowableToSingle.java

	@Test
	public void testFlowableToSingle() {
		Flowable.just("item1", "item2")
				.single("result")
				.test()
				.assertError(IllegalArgumentException.class)
				.assertErrorMessage("Sequence contains more than one element!");
	}