Add tests for Power Transformer

[veni-vidi-vici-dormivi]

So these fail because the bounds and first guess are not good. Hopefully, after merging #429 and #427 in here, the tests pass. They do locally with the new bounds and fg.

[veni-vidi-vici-dormivi]

Hm why are we not getting a codecov report here?

[mathause]

Hm why are we not getting a codecov report here?

The log gives a hint: https://github.com/MESMER-group/mesmer/pull/430/checks#step:8:55

Can't say that I understand it, though 🤭. I thought codecov was moving away from tokens, but they seem to recommend it again. Let me check what xarray does... Also why only this PR and why consistently?

[mathause]

Ah I think it's here: https://docs.codecov.com/docs/codecov-uploader#supporting-token-less-uploads-for-forks-of-open-source-repos-using-codecov (the last paragraph)

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 86.79%. Comparing base (9b0b76b) to head (c21905f). Report is 49 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #430 +/- ## ========================================== - Coverage 87.90% 86.79% -1.12% ========================================== Files 40 44 +4 Lines 1745 1954 +209 ========================================== + Hits 1534 1696 +162 - Misses 211 258 +47 ``` | [Flag](https://app.codecov.io/gh/MESMER-group/mesmer/pull/430/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=MESMER-group) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/MESMER-group/mesmer/pull/430/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=MESMER-group) | `86.79% <ø> (-1.12%)` | :arrow_down: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=MESMER-group#carryforward-flags-in-the-pull-request-comment) to find out more.

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[veni-vidi-vici-dormivi]

Ah now also the Codecov report's here :)

[veni-vidi-vici-dormivi]

We could add another test, but it is not really code related but rather of scientific nature: transform skewed data and test if it is actually less skewed afterwards. What do you think @mathause ?

[veni-vidi-vici-dormivi]

You ignored two of my comments, which I think are still valid.

Sorry, hadn't pushed them yet.

[veni-vidi-vici-dormivi]

Okay this got messy but now it's ready to merge.