Fix most warnings during tests

[djhoese]

In an effort to catch issues sooner, this PR configures pytest to error on any warnings. This is configured in pyproject.toml. This PR also includes a fix for the weber fechner stretching method where data was not clipped to what should be considered the minimum input stimuli (s0).

The 2 errors that are globally ignored by pytest are:

    "ignore::rasterio.errors.NotGeoreferencedWarning",
    # remove after #149 is merged
    "ignore:invalid value encountered in cast:RuntimeWarning",

The first one is to ignore all the times our test save to a geotiff but don't include an AreaDefinition so no geotransform information is set. This happens in so many spots I didn't want to try to fix them all in this PR and I'm not sure it is worth the time and effort.

The second, as mentioned in the comment, should be fixed when #149 gets merged.

• Closes #xxxx (remove if there is no corresponding issue, which should only be the case for minor changes)
• Tests added (for all bug fixes or enhancements)
• Tests passed (for all non-documentation changes)
• Passes git diff origin/master **/*py | flake8 --diff (remove if you did not edit any Python files)
• Fully documented (remove if this change should not be visible to users, e.g., if it is an internal clean-up, or if this is part of a larger project that will be documented later)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (cb62b3b) 91.60% compared to head (3a9f1ca) 91.57%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #157      +/-   ##
==========================================
- Coverage   91.60%   91.57%   -0.03%     
==========================================
  Files          12       12              
  Lines        4004     4014      +10     
==========================================
+ Hits         3668     3676       +8     
- Misses        336      338       +2     

Flag	Coverage Δ
unittests	91.57% <100.00%> (-0.03%)	⬇️

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[coveralls]

coverage: 91.808% (-0.03%) from 91.838%
when pulling 3a9f1ca on djhoese:remove-test-warnings
into cb62b3b on pytroll:main.

[mraspaud]

Lgtm!

[pnuu]

The first one is to ignore all the times our test save to a geotiff but don't include an AreaDefinition so no geotransform information is set. This happens in so many spots I didn't want to try to fix them all in this PR and I'm not sure it is worth the time and effort.

I added the area defs for writer tests in Satpy. If I get bored, I could start adding them also on Trollimage tests.

[djhoese]

I added the area defs for writer tests in Satpy. If I get bored, I could start adding them also on Trollimage tests.

I got a little nervous changing the tests because I know Martin modified some in his PR and didn't want to cause too many conflicts. Let me see how many there are...33 test failures.