FsCheck VS Moq

On the left corner, weighing in at v3.x, hailing from the OG PBT library, Haskell's QuickCheck, of which it's a direct port, we have FsCheck - F# premier PBT library, well established, battle-tested, community-driven, just solid.

As you can see from the imports statement we're relying on FsCheck to generate some random values for us.

C# - FsCheck

https://fscheck.github.io/FsCheck/ can hopefully generate random inputs automatically or with low effort for many methods to get your code coverage up. You don’t even need to write real tests right now, just call the methods with the random inputs and check they don’t fail.

Try using F# for tests. It has some great libraries like FsCheck (https://fscheck.github.io/FsCheck/).

At Symbolica we're building a symbolic execution service that explores every reachable state of a user's program and verifies assertions at each of these states to check that the program is correct. By default it will check for common undefined behaviours, such as out-of-bounds memory reads or divide by zero, but it can also be used with custom, application specific, assertions too just like the kind you'd write in a unit test. Seen from this perspective it's kind of like FsCheck (or Haskell's QuickCheck or Python's Hypothesis), but much more exhaustive and without the randomness.

Maybe something like QuickCheck, a quick search gave me this library for .NET https://github.com/fscheck/FsCheck

Because of the above I've generally been using tools like Stryker.NET and FsCheck to augment my testing suite. I'm still doing unit testing to find the more obvious "I haven't had my coffee, let's make sure I'm doing what I think I'm doing" bugs. I'm just using things like mutation testing, property testing, fuzzing, etc. to find the deeper issues in my code. There's a ton of libraries out there, including one that I've built for myself to help with testing but FsCheck and Stryker are just beautiful. And if you're interested in fuzzing, SharpFuzz is a great option. But that one isn't quite as easy of an on ramp compared to the other two that I mentioned.

Looks cool. Is there a reason why you didn't use FsCheck or Hedgehog? They're built to generate random data for testing, and can return the seed if a test fails so you can rerun the test with the exact same data once you figure out what the problem is - which is useful if the failure condition is rare.

Haskell has QuickCheck and Hedgehog, and dotnet has both as well. F# is favored, but there's C# interop.

8. Moq

In terms of mocking there are several frameworks you can use, but I've mainly relied on Moq and NSubstitute. Within this demo, I'm going to use NSubstitute as I've found it a little easier to use.

Or you just run into bullshit like https://github.com/Moq/moq4/issues/173

Now to the real benefit of DI: If you are testing a method in your application that calls the ReservationRepository.GetReservation() method, you can use a library like Moq to simply "mock" a class that uses the IReservationRepository interface and define the return result of the GetReservation() method. Pass the mocked class into the constructor of the class you are testing.

MOQ https://github.com/moq/moq4

Moq

Both projects use similar testing infrastructure. I write unit tests in C# using XUnit.net. I frequently use mock objects in testing, and MOQ is my tool of choice. I utilize continuous testing and coverage analysis through Rider. I do not have specific objectives for code coverage. When writing complicated algorithms, I frequently shoot for 100% coverage of the algorithm. I test simple properties inconsistently, and frequently do not test guard clauses.

🔗 Moq documentation | GitHub

But the reality is that I don't really write my tests with it. Toss on the MSTest attributes as needed of course. But all the testing code itself is FluentAssertions with a bit of Moq. (Though I find rarely need to use Moq/mocking anymore -- scandalous, I know.)