Background

This is another part of introducing pants, as discussed in various TSC meetings.

Related PRs can be found in:

• pantsbuild milestone (which includes PRs since Initialize pantsbuild #5713)
• pantsbuild label (which also includes preparatory PRs that came before adding pantsbuild)

Overview of this PR

In #5848, I will add a GHA workflow to run some tests via pants, starting with tests in pylint_plugins/. But, the current tests in pylint_plugins import from st2common because that was a quick way to throw together the tests. This is a problem because pylint_plugins/ and st2* each use different resolves (and therefore separate lockfiles). That means that pants puts together the sandbox for running the pylint_plugins tests, it will not include the st2* modules.

Note that running pylint ON our source code works just fine. In that case, pants knows we need pylint + any source plugins for pylint + the source code that pylint needs to inspect. For tests, however, everything is based on dependencies between targets. I could use a pants feature that puts our code in both the st2 and the pylint_plugins resolve, but that makes the lockfile and BUILD file management more complex.

So, I copied a few bits from st2common into a test fixture for the pylint_plugins tests. The Makefile runs the pylint_plugins tests just before it runs pylint, so look in the "CI / Compile" jobs to see the test results (which pass). I've also tested with pants in #5848 to make sure this change works for both ways to test this.