TST: Verify that float columns stay float after pivot (pandas-dev#7142)

Author: dsm054

pandas/tests/reshape/test_pivot.py

@@ -167,6 +167,21 @@ def test_pivot_dtypes(self):
         expected = Series(dict(float64=2))
         tm.assert_series_equal(result, expected)
 
+    def test_pivot_preserve_dtypes():
+        # GH 7142 regression test
+        v = np.arange(5, dtype=np.float64)
+        df = DataFrame({'f1': v, 'f2': v + 2.0,
+                        'b1': v <= 2, 'b2': v <= 3}).reset_index()
+
+        values_cols = [['f1', 'f2'], ['f1', 'f2', 'b2']]
+        for values in values_cols:
+            df_res = df.pivot_table(index='index', columns='b1',
+                                    values=values)
+            result = dict(df_res.dtypes)
+            expected = {col: np.dtype('O') if col[0].startswith('b')
+                        else np.dtype('float64') for col in df_res}
+            assert result == expected
+
     def test_pivot_no_values(self):
         # GH 14380
         idx = pd.DatetimeIndex(['2011-01-01', '2011-02-01', '2011-01-02',