[TestMethod] // test stubs public void Create_WithNullSample_ShouldReturnBadRequestResult() // ServiceMethodToBeTest_ExpectedInput_ExpectedBehavior() { // arrange sample = null; // act var result = sut.CreateSample(sample); // assert Assert.IsInstanceOfType(result, typeof(BadRequestResult)); mockService .Verify( s => s.Save(Guid.Empty, sample), Times.Never ); }