Hello, how would I fix this?

E       Exception: Rules with errors: 1
                     E         (TestResult, [PythonTestsAdaptor, PyTest, PythonSetup, SubprocessEncodingEnvironment], [Get(TransitiveHydratedTargets, BuildFileAddresses), Get(Pex, CreatePexFromTargetClosure), Get(SourceRootStrippedSources, Address), Get(ChrootedPythonSources, HydratedTargets), Get(Digest, DirectoriesToMerge), Get(FallibleExecuteProcessResult, ExecuteProcessRequest)], run_python_test()):
                     E           Was not usable by any other @rule.

I’m banging my head against the wall. This is the rule I’m testing in isolation - I don’t expect it to be called by anything else in my test’s rule graph? https://github.com/pantsbuild/pants/compare/master...Eric-Arellano:pytest-tests?expand=1