tests.unit.test_reader_v1_arrow: test_to_dataframe_empty_w_scalars_arrow failed

[flaky-bot]

This test failed!

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If I'm commenting on this issue too often, add the flakybot: quiet label and
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---

commit: 9550ea6
buildURL: Build Status, Sponge
status: failed

Test output

class_under_test = 
mock_gapic_client = 
def test_to_dataframe_empty_w_scalars_arrow(class_under_test, mock_gapic_client):
    arrow_schema = _bq_to_arrow_schema(SCALAR_COLUMNS)
    read_session = _generate_arrow_read_session(arrow_schema)
    arrow_batches = _bq_to_arrow_batches([], arrow_schema)
    mock_gapic_client.read_rows.return_value = arrow_batches
    reader = class_under_test(mock_gapic_client, "", 0, {})

    # Read session is needed to get a schema for empty streams.
    got = reader.to_dataframe(read_session)

    expected = pandas.DataFrame([], columns=SCALAR_COLUMN_NAMES)
    expected["int_col"] = expected["int_col"].astype("int64")
    expected["float_col"] = expected["float_col"].astype("float64")
    expected["bool_col"] = expected["bool_col"].astype("bool")
    expected["ts_col"] = (
        expected["ts_col"].astype("datetime64[ns]").dt.tz_localize("UTC")
    )


  pandas.testing.assert_frame_equal(


        got.reset_index(drop=True),  # reset_index to ignore row labels
        expected.reset_index(drop=True),
    )

E       AssertionError: Attributes of DataFrame.iloc[:, 8] (column name="ts_col") are different

E

E       Attribute "dtype" are different

E       [left]:  datetime64[us, UTC]

E       [right]: datetime64[ns, UTC]
tests/unit/test_reader_v1_arrow.py:260: AssertionError

[flaky-bot]

Looks like this issue is flaky. 😟

I'm going to leave this open and stop commenting.

A human should fix and close this.

---

When run at the same commit (9550ea6), this test passed in one build (Build Status, Sponge) and failed in another build (Build Status, Sponge).