Moq is a mocking library for .NET Unit Testing (cue the TDD folks reminding us mocks are unnecessary), and it is by far the most widely used mocking library in .NET (475 million downloads vs 87 million for the next largest, NSubstitute). Yesterday, its author released version 4.20.1; which added nagware and a backdoor to Moq, in a bid to drive up paid usages of Moq through ‘Sponsorships’. 

Unit testing is an integral part of modern software development. For years, Moq has been a popular choice in the .NET ecosystem for creating mock objects. Recent concerns over Moq’s SponsorLink feature have prompted some developers to consider such a switch. In this article, we delve into why you might consider NSubstitute over Moq and how to make the transition. 

Moq makes testing this piece of code a breeze. Without it, I would have had to write a whole lot of essentially throwaway code just to test this three line controller action. Probably one or two orders of magnitude more code. Clearly, this tool which I relied on heavily prior to .NET Core, remains quite a powerful weapon in my arsenal in .NET Core.