TST: change dtype on expected output instead of input

Author: Scorpil

pandas/tests/reshape/test_reshape.py

@@ -397,14 +397,14 @@ def test_dataframe_dummies_prefix_list(self, df, sparse):
 
     def test_dataframe_dummies_prefix_str(self, df, sparse):
         # not that you should do this...
-        df[['C']] = df[['C']].astype(np.uint8)
         result = get_dummies(df, prefix='bad', sparse=sparse)
         bad_columns = ['bad_a', 'bad_b', 'bad_b', 'bad_c']
         expected = DataFrame([[1, 1, 0, 1, 0],
                               [2, 0, 1, 1, 0],
                               [3, 1, 0, 0, 1]],
                              columns=['C'] + bad_columns,
                              dtype=np.uint8)
+        expected = expected.astype({"C": np.int64})
         assert_frame_equal(result, expected)
 
     def test_dataframe_dummies_subset(self, df, sparse):