One thing I've noticed is that this happens often when "Lightweight Solution Load" is enabled and projects the unit tests depend on aren't loaded. You can either disable "Lightweight Solution Load" or open the Configuration Manager to force the entire solution to load.

I updated to VS2017 today and now this is happening consistently every time I right click->debug a Selenium test in Test Explorer.. if I close the browser or hit the stop button it will act like it is continuing, so I will hit cancel at which point it will switch to saying "Canceling" and it will hang forever until I close and reopen VS.

I just updated to VS2017 and this now happens every single time I right click to debug a Selenium test. When I click cancel it will say "Canceling" and will stay in this state indefinitely

Same here with NUnit tests in a large solution with 229 Projects. Test Explorer keeps "spinning". Test output pane shows NUnit test adapter has finished but VS does not i.e. I get the first line below but NOT the second (from a successful completion). Disabling source

[19/03/2018 12:22:19 PM Informational] NUnit Adapter 3.10.0.21: Test discovery complete
[19/03/2018 12:22:20 PM Informational] ========== Discover test finished: 2901 found (0:00:11.7327234) ==========

...

By process of elimination I narrowed it down to this test that was showing up in the test output pane with the following warning. Giving it an explicit name using SetName() instead of relying on the long string parameter fixed the problem. Although oddly other similar warnings for shorter strings were not causing the same issue.

[24/03/2018 11:51:22 PM Warning] Contents of string 'SoftFurnishings.UnitTests.CurtainMFPricingConfigurationsUnitTest.FromJson_MigrationSample2_Matches(SoftFurnishings.CurtainMFPricingConfigurations,"..<long string>..")' exceeds max size of '1024'. String has been truncated.

Using

VS Pro 15.6.4

NUnit Test Adapter 3.10.0

NUnit 3.10.1

I have the same issue, discover tests never finishes. The project is a WAP. I'm using XUnit. The solution only has 4 projects in it; the WAP, 2 dlls, and the tests. There are only 39 tests in the test project. All projects target .Net 4.5.2.

I have included the current text from the Tests output window. I don't know what is meant by "None of the specified source(s)...is valid. Fix the above errors/warnings and then try again." because the indicated files are there.

In this instance at least, I don't believe the tests had not run since I had opened the solution. I started a build, then noticed that I didn't have the option selected to "Run tests after build", so while it was building, I clicked the button. I have done this in the past without issue. In this case I just did it a few minutes ago, maybe 10-15 now, but definitely not around 8:24am, which is the last timestamp on the output. In fact I don't know why the tests would have tried running at all this morning since as I mentioned, I didn't have the option turned on to run the tests after build.

I can confirm that the path ~\AppData\Local\Temp\VisualStudioTestExplorerExtensions\xunit.runner.visualstudio.2.1.0/build is empty as indicated in the output.

Closing and opening VS is also my solution. Although the same path mentioned above is still empty (the same error appeared in the output window after restarting VS), the tests were discovered and ran (automatically) without a problem after restarting VS.

I didn't notice anything out of sorts in Event Viewer that looks like it would be related.

I have Visual Studio Enterprise 2017, 15.6.4, and I don't even see an option for Lightweight Solution Load.

This issue has been fixed and is now available in our latest update. You can download the update via the in-product notification or from here: https://www.visualstudio.com/vs/ Thanks to everyone who provided feedback, votes and solutions for this problem.

I have a similar problem as well. It usually happens to me upon ending a test, like it is caught in an infinite loop and can't recover. I usually have to close Visual Studio and restart. And I do believe it has happened exclusively when I am debugging a test. This has been happening through several updates of Visual Studio 2017. I am currently on 15.3.4, and the problem still exists.