TST: fixes arithmetic tests for object output of period math

Author: deniederhut

pandas/tests/frame/test_arithmetic.py

@@ -245,7 +245,7 @@ def test_ops_frame_period(self):
         exp = pd.DataFrame({'A': np.array([2, 1], dtype=object),
                             'B': np.array([14, 13], dtype=object)})
         tm.assert_frame_equal(p - df, exp)
-        tm.assert_frame_equal(df - p, -exp)
+        tm.assert_frame_equal(df - p, -1 * exp)
 
         df2 = pd.DataFrame({'A': [pd.Period('2015-05', freq='M'),
                                   pd.Period('2015-06', freq='M')],
@@ -257,4 +257,4 @@ def test_ops_frame_period(self):
         exp = pd.DataFrame({'A': np.array([4, 4], dtype=object),
                             'B': np.array([16, 16], dtype=object)})
         tm.assert_frame_equal(df2 - df, exp)
-        tm.assert_frame_equal(df - df2, -exp)
+        tm.assert_frame_equal(df - df2, -1 * exp)

pandas/tests/series/test_arithmetic.py

@@ -315,15 +315,15 @@ def test_ops_series_period(self):
         # dtype will be object because of original dtype
         expected = pd.Series([9, 8], name='xxx', dtype=object)
         tm.assert_series_equal(per - ser, expected)
-        tm.assert_series_equal(ser - per, -expected)
+        tm.assert_series_equal(ser - per, -1 * expected)
 
         s2 = pd.Series([pd.Period('2015-01-05', freq='D'),
                         pd.Period('2015-01-04', freq='D')], name='xxx')
         assert s2.dtype == object
 
         expected = pd.Series([4, 2], name='xxx', dtype=object)
         tm.assert_series_equal(s2 - ser, expected)
-        tm.assert_series_equal(ser - s2, -expected)
+        tm.assert_series_equal(ser - s2, -1 * expected)
 
 
 class TestTimestampSeriesArithmetic(object):