From 03b6e06d058a90d252195cb3150d21d672cc09f3 Mon Sep 17 00:00:00 2001 From: Liang Yan Date: Thu, 15 Jun 2023 17:20:33 +0800 Subject: [PATCH] TST: Add test for duplcated columns and usecols GH#11823 Signed-off-by: Liang Yan --- pandas/tests/io/parser/test_mangle_dupes.py | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/pandas/tests/io/parser/test_mangle_dupes.py b/pandas/tests/io/parser/test_mangle_dupes.py index 5709e7e4027e8..4acbb82a5f23f 100644 --- a/pandas/tests/io/parser/test_mangle_dupes.py +++ b/pandas/tests/io/parser/test_mangle_dupes.py @@ -163,3 +163,14 @@ def test_mangle_dupe_cols_already_exists_unnamed_col(all_parsers): columns=["Unnamed: 0.1", "Unnamed: 0", "Unnamed: 2.1", "Unnamed: 2"], ) tm.assert_frame_equal(result, expected) + + +@skip_pyarrow +@pytest.mark.parametrize("usecol, engine", [([0, 1, 1], "python"), ([0, 1, 1], "c")]) +def test_mangle_cols_names(all_parsers, usecol, engine): + # GH 11823 + parser = all_parsers + data = "1,2,3" + names = ["A", "A", "B"] + with pytest.raises(ValueError, match="Duplicate names"): + parser.read_csv(StringIO(data), names=names, usecols=usecol, engine=engine)