TST: assure test_update_on_duplicate_frame_unique_argument_index chec…

…ks dtype

pandas/tests/frame/methods/test_update.py

@@ -224,8 +224,8 @@ def test_update_raises_on_duplicate_argument_index(self):
 
  def test_update_on_duplicate_frame_unique_argument_index(self):
  # GH#55509
- df = DataFrame({"a": [1, 1, 1]}, index=[1, 1, 2])
- other = DataFrame({"a": [2, 3]}, index=[1, 2])
- expected = DataFrame({"a": [2, 2, 3]}, index=[1, 1, 2])
+ df = DataFrame({"a": [1, 1, 1]}, index=[1, 1, 2], dtype=np.dtype("int_"))
+ other = DataFrame({"a": [2, 3]}, index=[1, 2], dtype=np.dtype("int_"))
+ expected = DataFrame({"a": [2, 2, 3]}, index=[1, 1, 2], dtype=np.dtype("int_"))
  df.update(other)
  tm.assert_frame_equal(df, expected)