Add test to trigger warning

aitikgupta · aitikgupta · commit 7a8aa99188c6 · 2021-05-26T01:04:39.000+05:30
diff --git a/lib/matplotlib/tests/test_ticker.py b/lib/matplotlib/tests/test_ticker.py
@@ -577,6 +577,18 @@ def test_cursor_dummy_axis(self, data, expected):
         fmt = sf.format_data_short
         assert fmt(data) == expected
 
+    def test_mathtext_ticks(self):
+        mpl.rcParams.update({
+            'font.family': 'serif',
+            'font.serif': 'cmr10',
+            'axes.formatter.use_mathtext': False
+        })
+
+        with pytest.warns(UserWarning, match='cmr10 font should ideally'):
+            fig, ax = plt.subplots()
+            ax.set_xticks([-1, 0, 1])
+            fig.canvas.draw()
+
 
 class FakeAxis:
     """Allow Formatter to be called without having a "full" plot set up."""
