public void ShouldGetLatestRestingHeartRateDate() { //Given var date = new DateTime(2018, 1, 5); _healthRepository.Setup(x => x.GetLatestRestingHeartRateDate()).Returns(date); //when var latestDate = _healthService.GetLatestRestingHeartRateDate(DateTime.MinValue); //then Assert.Equal(date, latestDate); }