After upgrading to NCrunch 3.13.0.7, I'm getting regular occurrences of an UnexpectedArgumentMatcherException. They're occurring at most once per test run, and the exception message is like this:



Re-running the test always clears the exception.

However, none of my tests use Arg.Any inside a Returns method call. An example line that produces this exception is


where _mockDateTimeProvider is an object created by AutoFixture, and _defaultDateTime is a static DateTime object.

Is there perhaps something else causing these exceptions, or is this an issue in the 3.13.0.7 version of NCrunch?

Thanks!

Thanks for the reply. I found that this issue was raised on StackOverflow a while ago - https://stackoverflow.com/questions/38283104.

In our case, a couple of tests were using AutoFixture's fixture.Create<T1>() method to build an object, and then passing Arg.Any<T2>() as a parameter in a method call on this object. This causes NSubstitute's static queue to get out-of-sync, as explained well here: https://weareadaptive.co.../09/30/why-nsubstitute/

Replacing these parameters with fixture.Create<T2>() fixed the issue.

So this was not a problem with NCrunch, but some change between 3.12.0.15 and 3.13.0.7 made this problem more likely to be visible. But that's a good thing!