Check that the formatter is the correct one

borgesaugusto · borgesaugusto · commit b66d739c013c · 2023-10-06T14:17:41.000+02:00
diff --git a/lib/matplotlib/tests/test_colorbar.py b/lib/matplotlib/tests/test_colorbar.py
@@ -15,7 +15,7 @@
     BoundaryNorm, LogNorm, PowerNorm, Normalize, NoNorm
 )
 from matplotlib.colorbar import Colorbar
-from matplotlib.ticker import FixedLocator, LogFormatter
+from matplotlib.ticker import FixedLocator, LogFormatter, StrMethodFormatter
 from matplotlib.testing.decorators import check_figures_equal
 
 
@@ -1234,4 +1234,5 @@ def test_colorbar_wrong_figure():
 
 def test_colorbar_format_string_and_old():
     plt.imshow([[0, 1]])
-    plt.colorbar(format="{x}%")
+    cb = plt.colorbar(format="{x}%")
+    assert isinstance(cb._formatter, StrMethodFormatter)
