Improve the coverage of the tests and fix some minor bugs

[lionelkusch]

I added in this pull request some simple tests (raise exceptions, used some options ...)

The aim of this pull request is to increase the coverage before starting to make a lot of modifications to the library.
The new tests are simple due to my lack of knowledge of the details of the different methods.

I don't take the time to format and comment on the additional tests; I will do it when I will reformat each method.

[lionelkusch]

Tis pull request is complementary to the pull request on the estimators #58 and #59 for having coverage close to 99%.
There still have a few lines of the code, which have not been tested.
The most important part will be in hidimstat/stat_coef_diff.py because there weren't any tests associated with it. If you have a suggestion, please share it with us.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.23%. Comparing base (19e6cf7) to head (85a6026).
Report is 94 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #64      +/-   ##
==========================================
+ Coverage   81.70%   84.23%   +2.53%     
==========================================
  Files          43       43              
  Lines        2312     2449     +137     
==========================================
+ Hits         1889     2063     +174     
+ Misses        423      386      -37     

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[bthirion]

Thx for taking care of that, this is super important.
Please take care of the syntax aspects.
How much does test time increase with this PR ? We need to be careful to keep it limited.

[lionelkusch]

How much does test time increase with this PR ? We need to be careful to keep it limited.

The time for the tests is still less than 5 min, as you can see in the report below.
The longest tests will be for the estimator (#57), going until 8 min for all tests. I suppose that is still good and the tests for the estimators can be run only when the estimators files are modified.

[bthirion]

8min is still fine, but we must be super careful here, because these numbers increase steadily.
The best way to do it is to identify which tests take the largest amount of time and see how to lower it.
But this is obviously not a priority for now.

[bthirion]

LGTM otherwise. Thx.

[lionelkusch]

@jpaillard

[bthirion]

The test part looks OK to me.

[jpaillard]

All good on my side

[lionelkusch]

I finally decided to remove the option for groups and I created the group by hand.

[bthirion]

LGTM overall. One more line needs coverage.

[lionelkusch]

I removed the line not covered because it will be modified in the PR #132.

[bthirion]

LGTM, thx.