public void UtilizesUserIdentityProvider() { // arrange var inputParams = Fixture.Create <CreatePackSchedule>(); var userIdentityProviderCalled = false; MockIdentityProvider.Setup(m => m.SetUserIdentity(It.IsAny <CreatePackScheduleParameters>())) .Callback((IUserIdentifiable p) => { userIdentityProviderCalled = true; }); // act SystemUnderTest.Post(inputParams); // assert MockIdentityProvider.Verify(m => m.SetUserIdentity(It.IsAny <CreatePackScheduleParameters>()), Times.Once()); Assert.True(userIdentityProviderCalled); }