public void BusinessRepository_CalculateTax_ShouldReturnDifferentThanExcepted(int taxA, int taxB, int expected) { // Arrange var repository = new Mock <IBusinessRepository>(); var businessService = new BusinessService(repository.Object); // Act var calcRet = businessService.CalculateTax(taxA, taxB); // Assert FluentAssertions Assert.NotEqual(calcRet, expected); }