Microsoft.Testing.Extensions.HangDump does not explain when hangdump triggers

[vikukush]

Hangdump documentation on https://learn.microsoft.com/en-us/dotnet/core/testing/microsoft-testing-platform-extensions-diagnostics does not contain information about

• How hangdump determines that "in case the test host process hangs" happened
• Consequently it is not explained what --hangdump-timeout actually affects

I thought that --hangdump-timeout is overall runtime, but apparently it's per test, I guess? But there's parallelization too, so does it work when just one test hangs? I have no idea, please fix the docs.

[MihuBot]

I'm a bot. Here is a possible related and/or duplicate issue (I may be wrong):

• --hangdump-timeout is for the whole test run instead of per-test on macOS #7060

[Evangelink]

Hi @vikukush,

Thanks for this valuable feedback, we will work on improving the documentation!

[nohwnd]

The way the hang is determined is by resetting a single timer in the process every time a test completes. So it is not per test. A 3 minute test will survive 30s hang timeout if other tests succeed in parallel at least every 30 seconds.

Hang dump timeout should be a bit longer than your longest test (just in case you run them in series and the test is unlucky to run last).

The goal is to give you dump of process where everything is already hanging (and would be hanging forever), and there are no tests running in parallel to avoid pointing at tests that are not hanging but just happened to run at the same time as the other test.

This makes investigating hangs much easier, especially for deadlocks.

This is different to a test timeout, test timeout is supposed to cancel test after the test takes too long.

[nohwnd]

https://github.com/dotnet/docs/blob/main/docs/core/testing/microsoft-testing-platform-extensions-diagnostics.md
https://grep.app/search?q=Generate+a+dump+file+if+the+test+process+hangs

You can help us improve the docs, by adding the info here.

Docs are best written by people who are not too deep in the internal knowledge of the tool 🙂

[Youssef1313]

Documentation with updated in dotnet/docs#51000 which I hope makes it clear enough. I'm going ahead and closing this.