I'm Itai from Applitools, and we currently use Travis-CI to build our .NET SDK.
We have two types of regression tests - generated and hand-written, both use NUnit.
While the generated test pass constantly, the hand-written test hangs at some point.
I tried to investigate where it happens, but it seems random, sometimes it doesn't even reach the actual test code. I added a print when the test is starting on the "Setup" method of the base class that's common for all the tests (the generated and the hand-written) with the test name and thread id, and on some hangs I see only this print. and no other prints (even though I have logs in almost every method, and in the "TearDown" common method).
At some point I see no more logs being written, and after 10 minutes Travis-CI kills the build claiming no logs were added in the last 10 minutes.
When I try to run the hanged tests locally they pass. I tried removing the "LevelOfParallelism" assembly attribute but it still happens.
I will continue to investigate it on my end, but since I saw several fixes for other CI systems in recent NUnit releases I thought I should ask here too.