Investigate adding more automated tests

[tvhong]

The automated tests available for this add-on is quite minimal. We want to add more automated tests to prevent regressions.

Let's use this issue to start the investigation.

Acceptance Criteria:

• Have a good understanding of which part of the add-on could be tested, and how much effort it would take.
• Document the findings here.

[tvhong]

I saw this this pytest-anki by glutanimate in https://github.com/artyompetrov/AutoDefine_oxfordlearnersdictionaries/blob/master/tests/tests.py .

We might be able to use it. But beware that there might be some problems running pytest-anki on MacOS.

[tvhong]

More tests would have prevented issues such as: #18

[tvhong]

Just noticed that pytest-anki hasn't seen new commits for 3 years. Probably not in a healthy place to use.

[tvhong]

Another concern is that the current code in the IR plugin is too tightly coupled with Anki and PyQt, making it extremely difficult to test.

We should first refactor the main logic into their own components and create unit tests for them.