Django не может создать тестовую базу данных с использованием MySQL

Question

Я разрабатываю большой проект Django и начинаю писать несколько тестов. Но я столкнулся с проблемой при запуске их. Когда я запускаю python manage.py test, я получаю следующую ошибку:

$ project/ python manage.py test
                    project/env/lib/python3.7/site-packages/django/db/models/base.py:319: RuntimeWarning: Model 'accounts.manager' was already registered. Reloading models is not advised as it can lead to inconsistencies, most notably with related models.
  new_class._meta.apps.register_model(new_class._meta.app_label, new_class)
Creating test database for alias 'default'...
Got an error creating the test database: (1007, "Can't create database 'test_partyadvisor'; database exists")
Type 'yes' if you would like to try deleting the test database 'test_partyadvisor', or 'no' to cancel: yes
Destroying old test database for alias 'default'...
Traceback (most recent call last):
  File "project/env/lib/python3.7/site-packages/django/db/backends/utils.py", line 62, in execute
    return self.cursor.execute(sql)
  File "project/env/lib/python3.7/site-packages/django/db/backends/mysql/base.py", line 101, in execute
    return self.cursor.execute(query, args)
  File "project/env/lib/python3.7/site-packages/MySQLdb/cursors.py", line 206, in execute
    res = self._query(query)
  File "project/env/lib/python3.7/site-packages/MySQLdb/cursors.py", line 312, in _query
    db.query(q)
  File "project/env/lib/python3.7/site-packages/MySQLdb/connections.py", line 224, in query
    _mysql.connection.query(self, query)
MySQLdb._exceptions.OperationalError: (1170, "BLOB/TEXT column 'content' used in key specification without a key length")

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "project/env/lib/python3.7/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "project/env/lib/python3.7/site-packages/django/core/management/__init__.py", line 356, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "project/env/lib/python3.7/site-packages/django/core/management/commands/test.py", line 29, in run_from_argv
    super(Command, self).run_from_argv(argv)
  File "project/env/lib/python3.7/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "project/env/lib/python3.7/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "project/env/lib/python3.7/site-packages/django/core/management/commands/test.py", line 62, in handle
    failures = test_runner.run_tests(test_labels)
  File "project/env/lib/python3.7/site-packages/django/test/runner.py", line 601, in run_tests
    old_config = self.setup_databases()
  File "project/env/lib/python3.7/site-packages/django/test/runner.py", line 546, in setup_databases
    self.parallel, **kwargs
  File "project/env/lib/python3.7/site-packages/django/test/utils.py", line 187, in setup_databases
    serialize=connection.settings_dict.get('TEST', {}).get('SERIALIZE', True),
  File "project/env/lib/python3.7/site-packages/django/db/backends/base/creation.py", line 69, in create_test_db
    run_syncdb=True,
  File "project/env/lib/python3.7/site-packages/django/core/management/__init__.py", line 131, in call_command
    return command.execute(*args, **defaults)
  File "project/env/lib/python3.7/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "project/env/lib/python3.7/site-packages/django/core/management/commands/migrate.py", line 204, in handle
    fake_initial=fake_initial,
  File "project/env/lib/python3.7/site-packages/django/db/migrations/executor.py", line 115, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "project/env/lib/python3.7/site-packages/django/db/migrations/executor.py", line 145, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "project/env/lib/python3.7/site-packages/django/db/migrations/executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "project/env/lib/python3.7/site-packages/django/db/migrations/migration.py", line 129, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "project/env/lib/python3.7/site-packages/django/db/migrations/operations/models.py", line 97, in database_forwards
    schema_editor.create_model(model)
  File "project/env/lib/python3.7/site-packages/django/db/backends/base/schema.py", line 319, in create_model
    self.execute(sql, params or None)
  File "project/env/lib/python3.7/site-packages/django/db/backends/base/schema.py", line 136, in execute
    cursor.execute(sql, params)
  File "project/env/lib/python3.7/site-packages/django/db/backends/utils.py", line 64, in execute
    return self.cursor.execute(sql, params)
  File "project/env/lib/python3.7/site-packages/django/db/utils.py", line 94, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "project/env/lib/python3.7/site-packages/django/utils/six.py", line 685, in reraise
    raise value.with_traceback(tb)
  File "project/env/lib/python3.7/site-packages/django/db/backends/utils.py", line 62, in execute
    return self.cursor.execute(sql)
  File "project/env/lib/python3.7/site-packages/django/db/backends/mysql/base.py", line 101, in execute
    return self.cursor.execute(query, args)
  File "project/env/lib/python3.7/site-packages/MySQLdb/cursors.py", line 206, in execute
    res = self._query(query)
  File "project/env/lib/python3.7/site-packages/MySQLdb/cursors.py", line 312, in _query
    db.query(q)
  File "project/env/lib/python3.7/site-packages/MySQLdb/connections.py", line 224, in query
    _mysql.connection.query(self, query)
django.db.utils.OperationalError: (1170, "BLOB/TEXT column 'content' used in key specification without a key length")

Тестовая база данных создана, но по какой-то причине я не могу ее использовать (?). Моя конфигурация базы данных (в файле settings.py):

DATABASES = {
        "default": {
            "ENGINE": "django.db.backends.mysql",
            "HOST": env.get("database").get("HOST"),
            "PORT": env.get("database").get("PORT"),
            "NAME": env.get("database").get("NAME"),
            "USER": env.get("database").get("USER"),
            "PASSWORD": env.get("database").get("PASS")
        }
}

Примечания:

1. Пользователь, которого я использую для доступа к БД, имеет все права на него.
2. Я попытался запустить тесты, используя пользователя root, и получил ту же ошибку.
3. Нормальный БД и кэш один работают отлично.
4. Также выполнил makemigrations и migrate.
5. Удалил тестовую базу данных из оболочки MySQL и заново запустил python manage.py test, получил ту же ошибку.
6. Опция --keep-db тоже не работает.

Система - это Ubuntu 18.04, и я использую Django 1.11 и MySQL 5.7.