TST: Fix failing pie plot tests

Author: TomAugspurger

pandas/tests/test_graphics.py

@@ -635,7 +635,7 @@ def test_pie_series(self):
         series = Series([1, 2, np.nan, 4],
                         index=['a', 'b', 'c', 'd'], name='YLABEL')
         ax = _check_plot_works(series.plot, kind='pie')
-        self._check_text_labels(ax.texts, series.index)
+        self._check_text_labels(ax.texts, ['a', 'b', '', 'd'])
 
     def test_pie_nan(self):
         s = Series([1, np.nan, 1, 1])
@@ -2798,13 +2798,17 @@ def test_pie_df_nan(self):
 
         base_expected = ['0', '1', '2', '3']
         for i, ax in enumerate(axes):
-            expected = list(base_expected)  # copy
+            expected = list(base_expected)  # force copy
             expected[i] = ''
             result = [x.get_text() for x in ax.texts]
             self.assertEqual(result, expected)
             # legend labels
-            self.assertEqual([x.get_text() for x in ax.get_legend().get_texts()],
-                              base_expected)
+            # NaN's not included in legend with subplots
+            # see https://github.com/pydata/pandas/issues/8390
+            self.assertEqual([x.get_text() for x in
+                              ax.get_legend().get_texts()],
+                             base_expected[:i] + base_expected[i+1:])
+
     def test_errorbar_plot(self):
         d = {'x': np.arange(12), 'y': np.arange(12, 0, -1)}
         df = DataFrame(d)

pandas/tools/plotting.py

@@ -2058,8 +2058,11 @@ def blank_labeler(label, value):
             # labels is used for each wedge's labels
             # Blank out labels for values of 0 so they don't overlap
             # with nonzero wedges
-            blabels = [blank_labeler(label, value) for
-                       label, value in zip(labels, y)]
+            if labels is not None:
+                blabels = [blank_labeler(label, value) for
+                           label, value in zip(labels, y)]
+            else:
+                blabels = None
             results = ax.pie(y, labels=blabels, **kwds)
 
             if kwds.get('autopct', None) is not None: