Why is the Visual Studio 2015/2017/2019 Test Runner not discovering my xUnit v2 tests

Answer 1

In my case I have multiple test projects in the same solution, and only one of the projects was not displaying the "Test Explorer"

I went to the "Manage Nuget Package for Solution" by right-clicking on the solution.

I noticed under the "Consolidate" tab there was some "Test" nuget packages that were out of sync between the projects. I clicked on "Install" and my missing tests showed up.

Answer 2

It's happened to me a couple of times - when I Clean the project and Build it again it tends to be fine.

Answer 3

The reason in my case was the target build was not the same between project debugger and test runner. To unify those elements:

1. Test>Test Settings>Default Processor Architecture. then select either X64 or X86.
2. Project>(your project)Properties>Build(tab)>platform target.

After they are identical, rebuild your solution then test methods will appear for you.

Answer 4

The most common culprit for me has been Visual Studio trying to run the tests using a different architecture than the library it's testing. Unfortunately there are multiple places where it seems this can go wrong.

In VS 2017, try creating a Run Settings file, e.g. Default.runsettings in your test project. If your main lib is x64, the contents should be:

<?xml version="1.0" encoding="utf-8"?>
<RunSettings>
  <RunConfiguration>
    <TargetPlatform>x64</TargetPlatform>
  </RunConfiguration>
</RunSettings>

Then choose this file from Test -> Test Settings -> Select Test Settings File.

Then, under Test -> Test Settings, Default Processor Architecture, choose the correct architecture again.

Be sure to Clean and Build the entire solution. You may need to close and reopen the Test Explorer window. Look for any additional errors in the Output -> Test window, for more clues about incorrect architecture types.

FYI additional Test Settings entries can be found here.

Answer 5

My problem was resolved by installing the nuget xunit.runner.visualstudio

Answer 6

Install xunit.runner.visualstudio package for the test project