The testrunner tries to discover the unit tests in xunit.runner.visualstudio.testadapter.dll. Why? Because it matches the default test sources spec of *.test*.dll.
When changing the default test source spec to *.tests.dll or something else more specific, it will work.
Source: http://erictummers.wordpress.com/2014/02/11/execute-xunit-tests-on-hosted-build-controller/
You can use xunit to unit test on the hosted build controller by installing the xunit.runner.visualstudio package.
But when the Build is done, there was an error.
The testrunner tries to discover the unittests in
xunit.runner.visualstudio.testadapter.dll. Why? Because it matches the
default test sources spec of *.test*.dll.
Change the spec to something more specific (like *unittest.dll) and everything works fine.
