I'm starting to work on some tests for my plugin. I think I need option 4 https://www.pantsbuild.org/docs/rules-api-testing#approach-4-run_pants-integration-tests-for-pants but the example test is failing for me:

pants.base.build_root.BuildRoot.NotFoundError: No build root detected. Pants detects the build root by looking for at least one file from ['pants', 'BUILDROOT', 'BUILD_ROOT'] in the cwd and its ancestors. If you have none of these files, you can create an empty file in your build root.

From the code I would expect

setup_tmpdir

to do this for me. I tried adding an empty file called BUILDROOT to the sources in the example but that didn't fix it either. Is this a known issue? Or am I missing something? I am running 2.11.0.rc2