self = 
project_id = 'precise-truck-742'
def test_struct(self, project_id):
    query = """SELECT 1 int_field,
               STRUCT("a" as letter, 1 as num) struct_field"""
    df = gbq.read_gbq(
        query,
        project_id=project_id,
        credentials=self.credentials,
        dialect="standard",
    )
    expected = DataFrame(
        [[1, {"letter": "a", "num": 1}]], columns=["int_field", "struct_field"],
    )


  tm.assert_frame_equal(df, expected)


E       AssertionError: Attributes of DataFrame.iloc[:, 0] (column name="int_field") are different

E

E       Attribute "dtype" are different

E       [left]:  Int64

E       [right]: int64
tests/system/test_gbq.py:847: AssertionError