How to use the etlhelper.iter_rows function in etlhelper

def test_iter_rows_dict_factory(pgtestdb_test_tables, pgtestdb_conn):
    sql = "SELECT * FROM src"
    result = iter_rows(sql, pgtestdb_conn, row_factory=dict_rowfactory)
    expected = [
        {'id': 1, 'value': 1.234, 'simple_text': 'text', 'utf8_text': 'Öæ°\nz',
         'day': datetime.date(2018, 12, 7),
         'date_time': datetime.datetime(2018, 12, 7, 13, 1, 59)},
        {'id': 2, 'value': 2.234, 'simple_text': 'text', 'utf8_text': 'Öæ°\nz',
         'day': datetime.date(2018, 12, 8),
         'date_time': datetime.datetime(2018, 12, 8, 13, 1, 59)},
        {'id': 3, 'value': 2.234, 'simple_text': 'text', 'utf8_text': 'Öæ°\nz',
         'day': datetime.date(2018, 12, 9),
         'date_time': datetime.datetime(2018, 12, 9, 13, 1, 59)},
         ]

    assert list(result) == expected

def test_copy_rows_transform(pgtestdb_conn, pgtestdb_test_tables, my_transform):
    # Arrange
    select_sql = "SELECT * FROM src"
    insert_sql = "INSERT INTO dest (id) VALUES (%s)"

    expected = [(2, None, None, None, None, None),
                (3, None, None, None, None, None)]

    # Act
    copy_rows(select_sql, pgtestdb_conn, insert_sql, pgtestdb_conn,
              transform=my_transform)

    # Assert
    sql = "SELECT * FROM dest"
    result = iter_rows(sql, pgtestdb_conn)
    assert list(result) == expected

def test_iter_rows_no_results(pgtestdb_test_tables, pgtestdb_conn):
    sql = "SELECT * FROM src WHERE id = -1"
    result = iter_rows(sql, pgtestdb_conn)
    assert list(result) == []

def test_iter_rows_transform(pgtestdb_test_tables, pgtestdb_conn,
                             test_table_data):
    # Arrange
    sql = "SELECT * FROM src"

    def my_transform(rows):
        # Simple transform function that changes size and number of rows
        return [row.id for row in rows if row.id > 1]

    # Act
    result = iter_rows(sql, pgtestdb_conn, transform=my_transform)

    # Assert
    expected = [row[0] for row in test_table_data if row[0] > 1]
    assert list(result) == expected

def test_copy_rows_happy_path(pgtestdb_conn, pgtestdb_test_tables,
                              pgtestdb_insert_sql, test_table_data):
    # Arrange and act
    select_sql = "SELECT * FROM src"
    insert_sql = pgtestdb_insert_sql.replace('src', 'dest')
    copy_rows(select_sql, pgtestdb_conn, insert_sql, pgtestdb_conn)

    # Assert
    sql = "SELECT * FROM dest"
    result = iter_rows(sql, pgtestdb_conn)
    assert list(result) == test_table_data

def test_iter_rows_happy_path(pgtestdb_test_tables, pgtestdb_conn,
                              test_table_data):
    sql = "SELECT * FROM src"
    result = iter_rows(sql, pgtestdb_conn)
    assert list(result) == test_table_data

def test_iter_rows_bad_query(pgtestdb_test_tables, pgtestdb_conn):
    sql = "SELECT * FROM public.this_does_not_exist"
    with pytest.raises(ETLHelperExtractError):
        result = iter_rows(sql, pgtestdb_conn)
        list(result)  # Call list to activate returned generator