refactor pytest

Author: charlesdong1991

pandas/tests/reshape/merge/test_merge.py

@@ -1455,8 +1455,11 @@ def test_merge_suffix(col1, col2, suffixes, expected_cols):
     a = pd.DataFrame({col1: [1, 2, 3]})
     b = pd.DataFrame({col2: [4, 5, 6]})
 
-    df = a.merge(b, left_index=True, right_index=True, suffixes=suffixes)
-    assert df.columns.tolist() == expected_cols
+    expected = pd.DataFrame([[1, 4], [2, 5], [3, 6]],
+                            columns=expected_cols)
+
+    result = a.merge(b, left_index=True, right_index=True, suffixes=suffixes)
+    tm.assert_frame_equal(result, expected)
 
 
 @pytest.mark.parametrize("suffixes", [