Following quickstart causes noisy errors on setUp

[RomHartmann]

First of all, thank you for wonderful work.

Following the quickstart at https://pypi.org/project/testing.mysqld/, I would get this very noisy error message:

.{base.py:680} ERROR - Exception during reset or similar
Traceback (most recent call last):
  File "/Users/romanhartmann/.virtualenvs/ub-data-product/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 671, in _finalize_fairy
    fairy._reset(pool)
  File "/Users/romanhartmann/.virtualenvs/ub-data-product/lib/python3.6/site-packages/sqlalchemy/pool/base.py", line 858, in _reset
    pool._dialect.do_rollback(self)
  File "/Users/romanhartmann/.virtualenvs/ub-data-product/lib/python3.6/site-packages/sqlalchemy/dialects/mysql/base.py", line 2227, in do_rollback
    dbapi_connection.rollback()
  File "/Users/romanhartmann/.virtualenvs/ub-data-product/lib/python3.6/site-packages/pymysql/connections.py", line 430, in rollback
    self._read_ok_packet()
  File "/Users/romanhartmann/.virtualenvs/ub-data-product/lib/python3.6/site-packages/pymysql/connections.py", line 394, in _read_ok_packet
    pkt = self._read_packet()
  File "/Users/romanhartmann/.virtualenvs/ub-data-product/lib/python3.6/site-packages/pymysql/connections.py", line 657, in _read_packet
    packet_header = self._read_bytes(4)
  File "/Users/romanhartmann/.virtualenvs/ub-data-product/lib/python3.6/site-packages/pymysql/connections.py", line 707, in _read_bytes
    CR.CR_SERVER_LOST, "Lost connection to MySQL server during query")
pymysql.err.OperationalError: (2013, 'Lost connection to MySQL server during query')

My unit test setup was like this:

class TestWhatever(unittest.TestCase):

    def setUp(self):
        self.mysql = testing.mysqld.Mysqld(port=7531)
        self.target_conn = create_engine(self.mysql.url()).connect()
        self.target_conn.execute("""CREATE TABLE `foo` (blah)""")

    def tearDown(self):
        self.target_conn.execute("DROP TABLE foo")
        self.mysql.stop()

    def test_something(self):
        # something useful

This error did not cause any tests to fail, it was just being logged all the time.
I was using the exact same setup for testing.postgresql without the error.

I changed my test class to this to get rid of the error:

MYSQLD_FACTORY = testing.mysqld.MysqldFactory(cache_initialized_db=True, port=7531)


def tearDownModule():
    """Tear down databases after test script has run.

    https://docs.python.org/3/library/unittest.html#setupclass-and-teardownclass
    """
    MYSQLD_FACTORY.clear_cache()


class TestWhatever(unittest.TestCase):

    @classmethod
    def setUpClass(cls):
        cls.mysql = MYSQLD_FACTORY()
        cls.target_conn = create_engine(cls.mysql.url()).connect()

    def setUp(self):
        self.mysql.start()
        self.target_conn.execute("""CREATE TABLE `foo` (blah)""")

    def tearDown(self):
        self.target_conn.execute("DROP TABLE foo")

    @classmethod
    def tearDownClass(cls):
        cls.mysql.stop()

    def test_something(self):
        # something useful

Would you please update your documentation to either

• Outline what I did wrong to prevent other people having to figure this out. I've seen a lot of SO posts about the vague pymysql.err.OperationalError: (2013, 'Lost connection to MySQL server during query') error in relation to this package
• Document this pattern as a working pattern