Write tests for the split shell functionality

[emmuhamm]

This is gonna be an interesting one

• will need different processes to run the different shells

  • PM
  • PM Shell
  • US
  • Controller shell

• Will need to have each of them interact with one another

• Make sure that the commands all work as expected

[PawelPlesniak]

sh.Command/sys.call as options

[emmuhamm]

this is integ test

[emmuhamm]

so for this, we want to have an integtest in the end, but this is gonna take a whole lot of time.

For now, what we can do is make a pytest (unit test) since we can run the PM as a subprocess by itself
make a config that is light, use fakedaqapp (see next funny pr)

also check out the sh command and syscalls

[PawelPlesniak]

We will need to have tests as

• Unified shell
• standalone process manager + unified shell
• standalone process manager + standalone process manager shell + controller shell

[PawelPlesniak]

This has been discussed in a meeting between @emmuhamm @bieryAtFnal and myself.

@bieryAtFnal has demonstrated an example on how this could me implemented, and this is issue will make use of the demonstrated features. This issue will target exercising the basic functionality of this split-shell operating mode, to validate that the independent control processes can operate together in the expected way.

Additional tests that will be useful to define will mimic the existing integration testst that are driven through the unified shell, e.g. the process_manager_test.py test will be duplicated, but instead of relying on drunc-unified-shell to drive these tests, we will want tests that exercise the drunc-process-manager and drunc-process-manager-shell independently. We will want to build similar tests for the drunc-controller-shell too.