WARN: fix some warnings

catch warning on reindexing a boolean indexer
add some documentation on a na scalar comparison test warning
remove warning for plotting multiple on a sub-plot

closes #12320
closes #8397

Author: jreback

pandas/tests/frame/test_indexing.py

@@ -212,9 +212,13 @@ def test_getitem_boolean(self):
         assert_frame_equal(subframe_obj, subframe)
 
         # test that Series indexers reindex
-        indexer_obj = indexer_obj.reindex(self.tsframe.index[::-1])
-        subframe_obj = self.tsframe[indexer_obj]
-        assert_frame_equal(subframe_obj, subframe)
+        # we are producing a warning that since the passed boolean
+        # key is not the same as the given index, we will reindex
+        # not sure this is really necessary
+        with tm.assert_produces_warning(UserWarning):
+            indexer_obj = indexer_obj.reindex(self.tsframe.index[::-1])
+            subframe_obj = self.tsframe[indexer_obj]
+            assert_frame_equal(subframe_obj, subframe)
 
         # test df[df > 0]
         for df in [self.tsframe, self.mixed_frame,

pandas/tests/series/test_operators.py

@@ -1197,8 +1197,16 @@ def tester(a, b):
         # TODO: Fix this exception - needs to be fixed! (see GH5035)
         # (previously this was a TypeError because series returned
         # NotImplemented
+
+        # this is an alignment issue; these are equivalent
+        # https://github.com/pydata/pandas/issues/5284
+
+        self.assertRaises(ValueError, lambda: d.__and__(s, axis='columns'))
         self.assertRaises(ValueError, tester, s, d)
 
+        # this is wrong as its not a boolean result
+        # result = d.__and__(s,axis='index')
+
     def test_operators_corner(self):
         series = self.ts
 

pandas/tests/test_graphics_others.py

@@ -425,18 +425,24 @@ def test_scatter_matrix_axis(self):
         with tm.RNGContext(42):
             df = DataFrame(randn(100, 3))
 
-        axes = _check_plot_works(scatter_matrix, filterwarnings='always',
-                                 frame=df, range_padding=.1)
+        # we are plotting multiples on a sub-plot
+        with tm.assert_produces_warning(UserWarning):
+            axes = _check_plot_works(scatter_matrix, filterwarnings='always',
+                                     frame=df, range_padding=.1)
         axes0_labels = axes[0][0].yaxis.get_majorticklabels()
+
         # GH 5662
         expected = ['-2', '-1', '0', '1', '2']
         self._check_text_labels(axes0_labels, expected)
         self._check_ticks_props(
             axes, xlabelsize=8, xrot=90, ylabelsize=8, yrot=0)
 
         df[0] = ((df[0] - 2) / 3)
-        axes = _check_plot_works(scatter_matrix, filterwarnings='always',
-                                 frame=df, range_padding=.1)
+
+        # we are plotting multiples on a sub-plot
+        with tm.assert_produces_warning(UserWarning):
+            axes = _check_plot_works(scatter_matrix, filterwarnings='always',
+                                     frame=df, range_padding=.1)
         axes0_labels = axes[0][0].yaxis.get_majorticklabels()
         expected = ['-1.2', '-1.0', '-0.8', '-0.6', '-0.4', '-0.2', '0.0']
         self._check_text_labels(axes0_labels, expected)