No output from Tests when running with xUnit v3

[wasker]

My setup is Visual Studio 2026 and xUnit v2.9.3. When I run tests in Visual Studio, I can see output from stdout in Output window with "Show output from Tests" selected. The output is coming from the unit under test and not from test cases themselves (i.e., not related to ITestOutputHelper).

After upgrading to xUnit v3, I can see the same output only when running dotnet test --logger "console;verbosity=detailed" but not when running from Visual Studio. In Visual Studio I only see "Connecting to client host '127.0.0.1' port '60184'" and the final tally.

How to get the output working in Visual Studio again?

[Tenno641]

See the docs: docs/capturing-output

In xUnit v3, capturing Console/stdout is disabled by default for backward compatibility with v2.

You can turn it on with these assembly-level attributes which will affect all tests in a unit test project.

// Both standard output and standard error
[assembly: CaptureConsole]

// Only standard output
[assembly: CaptureConsole(CaptureError = false)]

// Only standard error
[assembly: CaptureConsole(CaptureOutput = false)]

[wasker]

Thanks, but that's the thing - xUnit 2 somehow was outputting stdout in VS2026 for me without any customizations. I added that assembly attribute before filing the bug and it didn't make any difference when running in Visual Studio.

[bradwilson]

To be clear, "we" (as in xUnit.net) have not changed our behavior here. In both v2 and v3, we do not capture the console by default. What's changed is the introduction of support for Microsoft Testing Platform in v3 (v2 does not support this) and now the default behavior of Test Explorer in this situation is different.

So, in a sense, it "looks" like something changed in v3, but in reality, it changed when you stopped using VSTest and instead started using Microsoft Testing Platform (although this change was mostly silently done by default).

Aside from using the CaptureConsole attribute mentioned above, you can disable Microsoft Testing Platform entirely by swapping out the xunit.v3 package for xunit.v3.mtp-off package (or xunit.v3.core for xunit.v3.core.mtp-off). Or, if you prefer to leave MTP on but tell Test Explorer to behave in the old way, there are instructions here on how to disable it. (It's probably worth noting that I have no idea how much longer this "disable switch" will work, because at some point Test Explorer will turn off VSTest support entirely... not necessarily soon, but who knows when precisely.)

[wasker]

Thank you, I found it. CaptureConsole works after all. Last night I was looking for the output in the Output window, but the log is collected and accessible through the test explorer. That also works.