Where and when is your code running that you're looking for this API?

As per the link in the request, the JetBrains Rider team would like to add a unit test diff tool similar to what they have in IntelliJ, but can't provide it without the API. See https://www.youtube.com/watch?v=R8l6D3qGSdg for an example of the tool working using JUnit.

That doesn't really answer my questions as to what kind of an API you'd expect, and to be called at what stage during the process. Are you post-processing our XML file? Are you writing a test runner? etc.

Yes, it is extending the current runner in Rider. @gorohoroh, could you provide @bradwilson with some details on this please?

I'd rather ask @AndreyAkinshin to provide any details and API expectations beyond what's covered in the comment.

@bradwilson, @andyczerwonka, @gorohoroh
Sorry for late reply. We have own runner which directly use managed API. I guess, the best option will be extending of the IFailureInformation interface, it should provide additional metadata which can be used in Rider. Specifically, we need 3 additional fields: the full actual value, the full expected value, and the "assert kind" (e.g., Equals, Contains, and so on).

Any updates?

I think this feature is really needed by the compiler and tooling community (I'm in the community btw). There is really common pattern when some input data like a code is being processed and the result artefact (like code in the target language, intermediate representation, etc) is being compared with the expected one. In this case you need to understand where is that hucking extra space or comma

In the JVM world we already have JUnit which assertions have these fields. It is really useful, see video from andyczerwonka in the JB YouTrack

@vldF This is not currently on our backlog.