TST: fix warning for pie chart (#37669)

Author: ivanovmg

pandas/tests/plotting/test_frame.py

@@ -2650,11 +2650,20 @@ def test_pie_df(self):
             self._check_colors(ax.patches, facecolors=color_args)
 
     def test_pie_df_nan(self):
+        import matplotlib as mpl
+
         df = DataFrame(np.random.rand(4, 4))
         for i in range(4):
             df.iloc[i, i] = np.nan
         fig, axes = self.plt.subplots(ncols=4)
-        df.plot.pie(subplots=True, ax=axes, legend=True)
+
+        # GH 37668
+        kwargs = {}
+        if mpl.__version__ >= "3.3":
+            kwargs = {"normalize": True}
+
+        with tm.assert_produces_warning(None):
+            df.plot.pie(subplots=True, ax=axes, legend=True, **kwargs)
 
         base_expected = ["0", "1", "2", "3"]
         for i, ax in enumerate(axes):