public void ShouldAssertOccurenceWhenCombinedWithNoSetupCalls() { string userName = "******"; string password = "******"; ILoginService service = Mock.Create <ILoginService>(); Mock.Arrange(() => service.ValidateUser(userName, password)).Returns(5).OccursOnce(); Mock.Arrange(() => service.ValidateUser("foo", "bar")).OccursNever(); SecurityHandler handler = new SecurityHandler(service); bool loggedIn = handler.LoginUser(userName, password); Assert.True(loggedIn); Assert.Equal(handler.UserID, 5); Mock.Assert(service); }