From 86a826948c4deb424478313213ce4398f60f4ac2 Mon Sep 17 00:00:00 2001 From: TrigonaMinima Date: Tue, 19 Feb 2019 11:59:32 +0530 Subject: [PATCH] #23049: test for Fatal Stack Overflow stemming From Misuse of astype('category') --- pandas/tests/frame/test_combine_concat.py | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/pandas/tests/frame/test_combine_concat.py b/pandas/tests/frame/test_combine_concat.py index 59497153c8524..c2364dc135a9a 100644 --- a/pandas/tests/frame/test_combine_concat.py +++ b/pandas/tests/frame/test_combine_concat.py @@ -504,6 +504,16 @@ def test_concat_numerical_names(self): names=[1, 2])) tm.assert_frame_equal(result, expected) + def test_concat_astype_dup_col(self): + # gh 23049 + df = pd.DataFrame([{'a': 'b'}]) + df = pd.concat([df, df], axis=1) + + result = df.astype('category') + expected = pd.DataFrame(np.array(["b", "b"]).reshape(1, 2), + columns=["a", "a"]).astype("category") + tm.assert_frame_equal(result, expected) + class TestDataFrameCombineFirst(TestData):