TST: Merge multiple cols with mixed columns/index (#29522)

Author: ryankarlos

pandas/tests/reshape/merge/test_multi.py

@@ -195,6 +195,27 @@ def test_merge_right_vs_left(self, left, right, sort):
 
  tm.assert_frame_equal(merged_left_right, merge_right_left)
 
+ def test_merge_multiple_cols_with_mixed_cols_index(self):
+ # GH29522
+ s = pd.Series(
+ range(6),
+ pd.MultiIndex.from_product([["A", "B"], [1, 2, 3]], names=["lev1", "lev2"]),
+ name="Amount",
+ )
+ df = pd.DataFrame(
+ {"lev1": list("AAABBB"), "lev2": [1, 2, 3, 1, 2, 3], "col": 0}
+ )
+ result = pd.merge(df, s.reset_index(), on=["lev1", "lev2"])
+ expected = pd.DataFrame(
+ {
+ "lev1": list("AAABBB"),
+ "lev2": [1, 2, 3, 1, 2, 3],
+ "col": [0] * 6,
+ "Amount": range(6),
+ }
+ )
+ tm.assert_frame_equal(result, expected)
+
  def test_compress_group_combinations(self):
 
  # ~ 40000000 possible unique groups