When NUnit executes, the output will be stored in this file. Even when specifying multiple files to test, all of the output it put into a single file. [--result]
The output file specified is relative to the agent's workspace so to reference the output directory of the workspace, you only need Output\ (not $Workspace$\Output). However you can still specify an absolute file location such as C:\myOutputFile.xml and the NUnit action will generate the output file in the correct location.
When Project Configuration has a value it will run the NUnit tests from either a Visual Studio or NUnit project rather then .dlls. This value tells NUnit which configuration should be used running the project (ie. Debug, Release, etc). This property must be given a value when you are running NUnit against projects. [--config]
Test Fixture allows you to specify a specific test fixture to execute. You must specify the full name of the test fixture along with the containing assembly. [--test]
For example: Tests.MyTests myProject.tests.dll.
Specify which version of the .NET framework should be used when running the NUnit action. [--framework]
The Using drop down is populated with any property collector whose namespace matches the pattern defined by the NUnit action. The pattern for this action is