Debugging the NUnit3TestAdapter

Enable Tracing

Before debugging the adapter, check the trace outputs, which can be enabled using runsettings, either from a file or the command line.

Enable the following features:

    <DumpXmlTestDiscovery>true</DumpXmlTestDiscovery>
    <DumpXmlTestResults>true</DumpXmlTestResults>

This will create a Dump folder under the executing bin directory, containing one file for each setting. These files include both the input from the testhost and the resulting data returned by the framework/engine.

Enabling debugging

Debugging the adapter is done by first creating a debug version of the adapter. You can then enable a debug run by passing one of the NUnit debug settings using runsettings.

The symbols are:

NUnit.DebugExecution
NUnit.DebugDiscovery
NUnit.Debug

The last setting is equal to setting both of the two above.

From command line, you can set these by adding

dotnet test -- NUnit.DebugExecution=true

If you want to do this using Visual Studio, you must add a runsettings file, and add these settings there to the NUnit section.

A detailed explanation of the process can be found in this blog post

Debugging earlier versions

See this blog post for details on that process.