Remove paho from mqqt unit test

[twiggler]

We remove an import at the top, but now have to import the unit under test in the test itself.

Closes #926

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.71%. Comparing base (aab863c) to head (d79a675).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #967   +/-   ##
=======================================
  Coverage   77.71%   77.71%           
=======================================
  Files         326      326           
  Lines       28543    28543           
=======================================
  Hits        22183    22183           
  Misses       6360     6360           

Flag	Coverage Δ
unittests	77.71% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[Miauwkeru]

It might also be an idea to remove mqtt from line 83 of the pyproject.toml as there now shouldn't be a dependency requiring it anymore during tests no?

[Miauwkeru]

I think this part is more useful in a fixture, and that all the other tests use that fixture.
as it now changes the global state of modules and doesn't clean it up afterwards.

It will throw import errors as soon as paho.mqtt is removed.

[twiggler]

In https://docs.pytest.org/en/stable/how-to/monkeypatch.html#how-to-monkeypatch-mock-modules-and-environments it says:

"The modifications will be undone after the requesting test function or fixture has finished" (emphasis mine)

(There is another problem though: the broker defines the client as an instance variable)

Update: "It will throw import errors as soon as paho.mqtt is removed" is indeed a problem.
Added fixture

[twiggler]

It might also be an idea to remove mqtt from line 83 of the pyproject.toml as there now shouldn't be a dependency requiring it anymore during tests no?

@Miauwkeru It is no longer required for the test, but it should still be when using the mqtt loader right?

Update: Understand now, dev are the test dependencies