def enforces_check_constraints(self):
        """Target database must also enforce check constraints."""

        return self.check_constraints + fails_on(
            self._mysql_not_mariadb_102,
            "check constraints don't enforce on MySQL, MariaDB<10.2"
        )

 def graceful_disconnects(self):
     """Target driver must raise a DBAPI-level exception, such as
     InterfaceError, when the underlying connection has been closed
     and the execute() method is called.
     """
     return fails_on(
                 "postgresql+pg8000", "Driver crashes"
             )

 def isolation_level(self):
     return only_on(
         ("postgresql", "sqlite", "mysql", "mssql"),
         "DBAPI has no isolation level support",
     ) + fails_on(
         "postgresql+pypostgresql",
         "pypostgresql bombs on multiple isolation level calls",
     )

    def implicit_decimal_binds(self):
        """target backend will return a selected Decimal as a Decimal, not
        a string.

        e.g.::

            expr = decimal.Decimal("15.7563")

            value = e.scalar(
                select([literal(expr)])
            )

            assert value == expr

        See :ticket:`4036`

        """

        return exclusions.fails_on("mysql+mysqldb", "driver specific")

    def implicit_decimal_binds(self):
        """target backend will return a selected Decimal as a Decimal, not
        a string.

        e.g.::

            expr = decimal.Decimal("15.7563")

            value = e.scalar(
                select([literal(expr)])
            )

            assert value == expr

        See :ticket:`4036`

        """

        # fixed for mysqlclient in
        # https://github.com/PyMySQL/mysqlclient-python/commit/68b9662918577fc05be9610ef4824a00f2b051b0
        def check(config):
            if against(config, "mysql+mysqldb"):
                # can remove once post 1.3.13 is released
                try:
                    from MySQLdb import converters
                    from decimal import Decimal

                    return Decimal not in converters.conversions
                except:
                    return True

            return against(
                config, "mysql+mysqldb"
            ) and config.db.dialect._mysql_dbapi_version <= (1, 3, 13)

        return exclusions.fails_on(check, "fixed for mysqlclient post 1.3.13")

 def duplicate_key_raises_integrity_error(self):
     return fails_on("postgresql+pg8000")

    def date_coerces_from_datetime(self):
        """target dialect accepts a datetime object as the target
        of a date column."""

        return fails_on('mysql+mysqlconnector')

 def isolation_level(self):
     return only_on(
                 ('postgresql', 'sqlite', 'mysql'),
                 "DBAPI has no isolation level support"
             ) + fails_on('postgresql+pypostgresql',
                       'pypostgresql bombs on multiple isolation level calls')

    def date_coerces_from_datetime(self):
        """target dialect accepts a datetime object as the target
        of a date column."""

        # does not work as of pyodbc 4.0.22
        return fails_on('mysql+mysqlconnector') + skip_if("mssql+pyodbc")

    def enforces_check_constraints(self):
        """Target database must also enforce check constraints."""

        return self.check_constraints + fails_on(
            ['mysql'], "check constraints don't enforce"
        )