Update tests for matplotlib 3.8.0rc1

[ksunden]

This is mostly a generalization of the tests to work with both old and new matplotlib

The only production code change is adding .flat to one line in the matrix annotation code, all other changes are test-only.

Mostly the test changes were allowing the collection being found to be a QuadContourSet, as well as allowing outputs like colors or coordinates to be sequences instead of singular values, or adding .flat to values which now get returned as input-shaped arrays instead of automatically flattened arrays.

I was able to avoid version checking for most things, aside from the minor tick expected value and explicitly checking the expected type in ax.collections. Though there are some version-checks by proxy of isinstance checks.

I did add a boolean flag to shift the filtering of empty paths from the test to the helper function for get_contour_coords, this is only used in one test for now, but made for a backwards compatible filtering step.

get_contour_coords will now return non-rectangular grids (Not actually clear to me that this is new) so some tests have additional loops before calling assert_array_equal I added assertions that the lengths were the same to avoid zip dropping the fact that one list was longer.

I have tested with both matplotlib v3.8.x (the backport branch for the 3.8 series) as well as released 3.7.2.

In my dev environment I am seing some numpy warnings (which are elevated to errors for 2 tests), but other than that all tests pass.

[codecov]

Codecov Report

Merging #3446 (779402f) into master (67a777a) will decrease coverage by 0.01%.
The diff coverage is 97.36%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3446      +/-   ##
==========================================
- Coverage   98.32%   98.32%   -0.01%     
==========================================
  Files          77       77              
  Lines       24403    24413      +10     
==========================================
+ Hits        23995    24004       +9     
- Misses        408      409       +1     

Files Changed	Coverage Δ
seaborn/matrix.py	96.18% <ø> (ø)
tests/test_distributions.py	99.73% <97.14%> (-0.07%)	⬇️
tests/_core/test_scales.py	100.00% <100.00%> (ø)

[mwaskom]

Thanks @ksunden for jumping in here with the quick help — I can confirm that this passes all test using the rc on my laptop too!

[mwaskom]

Ah dang, not sure these test updates are all correct. There was a (sometimes triggered) accession of the contours.collections inside seaborn's main codebase that was populating the collections list as previously expected. So the filter_empty addition allowed tests to pass using that data, but not once I fixed the deprecated (as opposed to broken) pattern :(

[ksunden]

Ah, darn, that was the trickiest bit that I was not quite as confident of (but it appeared to work for both old and new versions of mpl, so I went with it).

If I understand what's happening, the following patch should work:

diff --git a/tests/test_distributions.py b/tests/test_distributions.py
index 3b8418fb..54de2b04 100644
--- a/tests/test_distributions.py
+++ b/tests/test_distributions.py
@@ -2438,13 +2438,13 @@ class TestDisPlot:
         z = [0] * 80 + [1] * 20

         g = displot(x=x, y=y, col=z, kind="kde", levels=10)
-        l1 = sum(bool(get_contour_coords(c)) for c in g.axes.flat[0].collections)
-        l2 = sum(bool(get_contour_coords(c)) for c in g.axes.flat[1].collections)
+        l1 = sum(len(get_contour_coords(c, True)) for c in g.axes.flat[0].collections)
+        l2 = sum(len(get_contour_coords(c, True)) for c in g.axes.flat[1].collections)
         assert l1 > l2

         g = displot(x=x, y=y, col=z, kind="kde", levels=10, common_norm=False)
-        l1 = sum(bool(get_contour_coords(c)) for c in g.axes.flat[0].collections)
-        l2 = sum(bool(get_contour_coords(c)) for c in g.axes.flat[1].collections)
+        l1 = sum(len(get_contour_coords(c, True)) for c in g.axes.flat[0].collections)
+        l2 = sum(len(get_contour_coords(c, True)) for c in g.axes.flat[1].collections)
         assert l1 == l2

     def test_bivariate_hist_norm(self, rng):

i.e. using the filter_empty behavior for one additional test, and changing from bool to len, as there may be more than one now

(I just commented out the line which accessed cset.collections, so whatever the proper fix on that side is up to you :))