How to run/call a plugin from another running plugin

[jeffwright13]

I've got a pytest plugin (let's call it "pytest-a") that is working fine in its original form, invoked as pytest --a. I want to break this single, monolithic plugin into two separate and independent plugins: "pytest-a1" (which would basically do the initial pytest option-handling, file interfacing, input handling, etc.), and "pytest-a2" (the guts / main engine of the original plugin, where it handles all the test executions). I want this new guts-code to be able to be included/importable by other plugin code.

The way I envision this working is, pytest-a1 will be called from the command line in the same way as pytest-a was before. Then after everything is set up, pytest-a1 will hand off its execution to pytest-a2. After pytest-a2 is done handling the tests and crunching data, pytest-a1 will take back over and complete the overall test execution (teardown, reporting, etc.). The overall effect will be as if I just invoked pytest --a on the command line. But now I have the added flexibility that I can write other "front end" plugin code that can call pytest-a2.

My question is, how do I actually invoke pytest-a2's functionality from within pytest-a1 as it executes? Both pytest-a1 and pytest-a2 have their own command-line-options associated with them (--a1 and --a2 ), instead of the original monolithic plugin, which only had a single command-line option, --a. What I want to be able to do is run pytest --a1) and have it act as if pytest --a1 and pytest_a2 are being called together, essentially providing the same functionality as if I were calling the original pytest --a.

I hope this makes some sense. If not, I can get more concrete and point to the actual plugins' code.

[RonnyPfannschmidt]

The built-in junitxml plugin is a good example of this pattern