Add the missing docstrings to the mig/shared/fileio.py unit tests from PR48

[jonasbardino]

Add the missing docstrings to the mig/shared/fileio.py unit tests as follow up to PR #48.
Minor comment clean up and line length adjustment from autopep8.

[albu-diku]

I know I'm not great at docstrings, but adding one per test is something of a new requirement and I think is a little too much.

What has been written in those strings is an improvement that should be to the test name itself --that is what shows up on the command line when tests fail. I can't think of a reason we would opt to have non-descriptive test names and then a sperate string that clarifies what the test is checking.

Again, I'm not going to insist and it's not my call to make regarding the standards, so am voicing that I don't believe this to be a good idea for tests.

[jonasbardino]

I know I'm not great at docstrings, but adding one per test is something of a new requirement and I think is a little too much.

What has been written in those strings is an improvement that should be to the test name itself --that is what shows up on the command line when tests fail. I can't think of a reason we would opt to have non-descriptive test names and then a sperate string that clarifies what the test is checking.

Again, I'm not going to insist and it's not my call to make regarding the standards, so am voicing that I don't believe this to be a good idea for tests.

The changes were really only in order to add the missing mandatory docstrings on classes and non-obvious functions as per the old TODO comment.
It's not a requirement for trivial functions or self-explaining test methods, and in this case I got them for free when I just asked aider to fix docstrings because I couldn't be bothered.
The docstring shows up in the output as user friendly explanation when a test fails so it's not completely pointless, but I agree that test names themselves should in most cases suffice.