Mock an update method returning a void with Moq

If you just want to verify this method is called, you should use Verifiable() method.

_mockUserRepository.Setup(mr => mr.Update(It.IsAny<int>(), It.IsAny<string>()))
                   .Verifiable();

If you also want to do something with those parameters, use Callback() first.

_mockUserRepository.Setup(mr => mr.Update(It.IsAny<int>(), It.IsAny<string>()))
                   .Callback((int id, string lastName) => {
                       //do something
                       }).Verifiable();

Update

Here’s how you should mock it if you return a bool value as result.

_mockUserRepository.Setup(mr => mr.Update(It.IsAny<int>(), It.IsAny<string>()))
                   .Returns(true);