Added a test

pharshalp · pharshalp · commit 7bb4313ea10f · 2022-01-12T20:59:47.000-05:00
diff --git a/lib/matplotlib/tests/test_colorbar.py b/lib/matplotlib/tests/test_colorbar.py
@@ -1,5 +1,6 @@
 import numpy as np
 import pytest
+import warnings
 
 from matplotlib import cm
 import matplotlib.colors as mcolors
@@ -938,3 +939,17 @@ def test_boundaries():
     fig, ax = plt.subplots(figsize=(2, 2))
     pc = ax.pcolormesh(np.random.randn(10, 10), cmap='RdBu_r')
     cb = fig.colorbar(pc, ax=ax, boundaries=np.linspace(-3, 3, 7))
+
+
+def test_colorbar_no_warning():
+    # github issue #21723 - If mpl style has 'axes.grid' = True,
+    # fig.colorbar raises a warning about Auto-removal of grids
+    # by pcolor() and pcolormesh(). This is fixed by PR #22216.
+    with warnings.catch_warnings(record=True) as w:
+        plt.rcParams['axes.grid'] = True
+        fig, ax = plt.subplots()
+        ax.grid(False)
+        im = ax.pcolormesh([0, 1], [0, 1], [[1]])
+        fig.colorbar(im)
+    # make sure that no warning is raised
+    assert len(w) == 0
