pytest-mysql

What is this?

A pytest plugin for tests that rely on a running MySQL or MariaDB database. It provides process and client fixtures.

Warning

Tested with MySQL 8.0+ and MariaDB 10.11+.

How to use

The plugin contains three fixtures:

• mysql - a function-scoped client fixture that drops the test database after each test to ensure repeatability.
• mysql_proc - a session-scoped process fixture that starts a local MySQL instance on first use and stops it at the end of the test session.
• mysql_noproc - a session-scoped fixture that connects to an already running MySQL instance.

Simply include one of these fixtures in your test fixture list.

You can also create additional MySQL client and process fixtures if you need to:

from pytest_mysql import factories
from getpass import getuser

mysql_my_proc = factories.mysql_proc(
    port=None, user=getuser())
mysql_my = factories.mysql('mysql_my_proc')

Note

Each MySQL process fixture can be configured in a different way than the others through the fixture factory arguments.

Prerequisites

Install MySQL or MariaDB on the machine where tests are executed. This plugin relies on binaries provided by those installations (for example mysqld and mysqladmin).

Use mysql_proc to start a local MySQL process from installed binaries. Use mysql_noproc to connect to an already running MySQL/MariaDB server.

Quickstart: first test

Install the plugin:

pip install pytest-mysql

Create a minimal test that uses the built-in fixture:

def test_mysql_fixture_available(mysql):
    assert mysql is not None

Run your tests:

pytest -q

Configuration

You can define settings in three ways: fixture factory arguments, command-line options, and pytest.ini configuration options. These settings are applied in the following order:

• Fixture factory argument
• Command-line option
• Configuration option in your pytest.ini file

Configuration options

MySQL/MariaDB option	Fixture factory argument	Command line option	pytest.ini option	Noproc process fixture	Default
Path to executable	mysqld_exec	--mysql-mysqld	mysql_mysqld		mysqld
Path to safe executable	mysqld_safe	--mysql-mysqld-safe	mysql_mysqld_safe		mysqld_safe
Path to mysql_install_db for legacy installations	install_db	--mysql-install-db	mysql_install_db		mysql_install_db
Path to Admin executable	admin_executable	--mysql-admin	mysql_admin		mysqladmin
Database hostname	host	--mysql-host	mysql_host	yes	localhost
Database port	port	--mysql-port	mysql_port	yes (3306)	random
Free port search count	port_search_count	--mysql-port-search-count	mysql_port_search_count		5
MySQL user to work with	user	--mysql-user	mysql_user		root
User's password	passwd	--mysql-passwd	mysql_passwd
Test database name	dbname	--mysql-dbname	mysql_dbname		test
Starting parameters	params	--mysql-params	mysql_params

Example usage:

• pass it as an argument in your own fixture

  mysql_proc = factories.mysql_proc(
      port=8888)

• use --mysql-port command line option when you run your tests

  pytest tests --mysql-port=8888
  

• specify your port as mysql_port in your pytest.ini file

  To do so, put a line like the following under the [pytest] section of your pytest.ini:

  [pytest]
  mysql_port = 8888

Examples

The examples below show advanced integration patterns after your first smoke test is passing.

Populating database for tests

With SQLAlchemy

This example shows how to populate the database and create an SQLAlchemy ORM connection:

The sample below is a simplified session fixture from pyramid_fullauth tests:

from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker
from sqlalchemy.pool import NullPool
from zope.sqlalchemy import register


@pytest.fixture
def db_session(mysql):
    """Session for SQLAlchemy."""
    from pyramid_fullauth.models import Base  # pylint:disable=import-outside-toplevel

    # assumes setting, these can be obtained from pytest-mysql config or mysql_proc
    connection = f'mysql+mysqldb://root:@127.0.0.1:3307/tests?charset=utf8'

    engine = create_engine(connection, echo=False, poolclass=NullPool)
    pyramid_basemodel.Session = scoped_session(sessionmaker(extension=ZopeTransactionExtension()))
    pyramid_basemodel.bind_engine(
        engine, pyramid_basemodel.Session, should_create=True, should_drop=True)

    yield pyramid_basemodel.Session

    transaction.commit()
    Base.metadata.drop_all(engine)


@pytest.fixture
def user(db_session):
    """Test user fixture."""
    from pyramid_fullauth.models import User
    from tests.tools import DEFAULT_USER

    new_user = User(**DEFAULT_USER)
    db_session.add(new_user)
    transaction.commit()
    return new_user


def test_remove_last_admin(db_session, user):
    """
    Sample test checks internal login, but shows usage in tests with SQLAlchemy
    """
    user = db_session.merge(user)
    user.is_admin = True
    transaction.commit()
    user = db_session.merge(user)

    with pytest.raises(AttributeError):
        user.is_admin = False

Note

See the original code at pyramid_fullauth's conftest file. Depending on your needs, that in between code can fire alembic migrations in case of sqlalchemy stack or any other code

Connecting to MySQL/MariaDB (in a docker)

To connect to MySQL or MariaDB running in Docker, use noproc fixtures.

docker run --name some-db -e MYSQL_ALLOW_EMPTY_PASSWORD=yes -d mysql --expose 3306

docker run --name some-db -e MARIADB_ALLOW_EMPTY_PASSWORD=yes -d mariadb --expose 3306

This starts MySQL/MariaDB in a Docker container, but using a locally installed MySQL or MariaDB instance is similar.

In tests, make sure your tests use the mysql_noproc fixture like this:

mysql_in_docker = factories.mysql_noproc()
mysql = factories.mysql("mysql_in_docker")


def test_mysql_docker(mysql):
    """Run test."""
    cur = mysql.cursor()
    cur.query("CREATE TABLE pet (name VARCHAR(20), owner VARCHAR(20), species VARCHAR(20), sex CHAR(1), birth DATE, death DATE);")
    mysql.commit()
    cur.close()

And run tests:

pytest --mysql-host=127.0.0.1

Running on Docker/as root

MySQL and MariaDB refuse to run as root by default, but we can force them by setting user=root in the configuration file.

However, the most common and secure approach is to change the user that runs tests in Docker:

USER nobody

This line should switch your Docker process to run as user nobody. See this comment for example.

Package resources

• Bug tracker: https://github.com/dbfixtures/pytest-mysql/issues

Release

Install pipenv and --dev dependencies first, then run:

pipenv run tbump [NEW_VERSION]