TST: add tests for warnings and avoid warnings in tests

tacaswell · tacaswell · commit bbeb86f8d7de · 2022-12-16T16:49:22.000-05:00
diff --git a/lib/matplotlib/tests/test_animation.py b/lib/matplotlib/tests/test_animation.py
@@ -1,6 +1,7 @@
 import os
 from pathlib import Path
 import platform
+import re
 import subprocess
 import sys
 import weakref
@@ -233,8 +234,11 @@ def test_animation_repr_html(writer, html, want, anim):
         assert want in html
 
 
-@pytest.mark.parametrize('anim', [dict(frames=iter(range(5)))],
-                         indirect=['anim'])
+@pytest.mark.parametrize(
+    'anim',
+    [{'save_count': 10, 'frames': iter(range(5))}],
+    indirect=['anim']
+)
 def test_no_length_frames(anim):
     anim.save('unused.null', writer=NullMovieWriter())
 
@@ -330,9 +334,11 @@ def frames_generator():
 
             yield frame
 
+    MAX_FRAMES = 100
     anim = animation.FuncAnimation(fig, animate, init_func=init,
                                    frames=frames_generator,
-                                   cache_frame_data=cache_frame_data)
+                                   cache_frame_data=cache_frame_data,
+                                   save_count=MAX_FRAMES)
 
     writer = NullMovieWriter()
     anim.save('unused.null', writer=writer)
@@ -372,7 +378,9 @@ def animate(i):
             return return_value
 
     with pytest.raises(RuntimeError):
-        animation.FuncAnimation(fig, animate, blit=True)
+        animation.FuncAnimation(
+            fig, animate, blit=True, cache_frame_data=False
+        )
 
 
 def test_exhausted_animation(tmpdir):
@@ -440,3 +448,61 @@ def animate(i):
 
     # 5th frame's data
     ax.plot(x, np.sin(x + 4 / 100))
+
+
+@pytest.mark.parametrize('anim', [dict(klass=dict)], indirect=['anim'])
+def test_save_count_override_warnings_has_length(anim):
+
+    save_count = 5
+    frames = list(range(2))
+    match_target = (
+        f'You passed in an explicit {save_count=} '
+        "which is being ignored in favor of "
+        f"{len(frames)=}."
+    )
+
+    with pytest.warns(UserWarning, match=re.escape(match_target)):
+        anim = animation.FuncAnimation(
+            **{**anim, 'frames': frames, 'save_count': save_count}
+        )
+    assert anim._save_count == len(frames)
+    anim._init_draw()
+
+
+@pytest.mark.parametrize('anim', [dict(klass=dict)], indirect=['anim'])
+def test_save_count_override_warnings_scaler(anim):
+    save_count = 5
+    frames = 7
+    match_target = (
+        f'You passed in an explicit {save_count=} ' +
+        "which is being ignored in favor of " +
+        f"{frames=}."
+    )
+
+    with pytest.warns(UserWarning, match=re.escape(match_target)):
+        anim = animation.FuncAnimation(
+            **{**anim, 'frames': frames, 'save_count': save_count}
+        )
+
+    assert anim._save_count == frames
+    anim._init_draw()
+
+
+@pytest.mark.parametrize('anim', [dict(klass=dict)], indirect=['anim'])
+def test_disable_cache_warning(anim):
+    cache_frame_data = True
+    frames = iter(range(5))
+    match_target = (
+        f"{frames=!r} which we can infer the length of, "
+        "did not pass an explicit *save_count* "
+        f"and passed {cache_frame_data=}.  To avoid a possibly "
+        "unbounded cache, frame data caching has been disabled. "
+        "To suppress this warning either pass "
+        "`cache_frame_data=False` or `save_count=MAX_FRAMES`."
+    )
+    with pytest.warns(UserWarning, match=re.escape(match_target)):
+        anim = animation.FuncAnimation(
+            **{**anim, 'cache_frame_data': cache_frame_data, 'frames': frames}
+        )
+    assert anim._cache_frame_data is False
+    anim._init_draw()
