@Test
public void testAverageOfAFewFloats() throws Throwable {

    Observable<Float> src = Observable.from(1.0f, 2.0f);
    averageFloats(src).subscribe(wf);
    verify(wf, times(1)).onNext(anyFloat());
    verify(wf).onNext(1.5f);
    verify(wf, never()).onError(any(Throwable.class));
    verify(wf, times(1)).onCompleted();
}