1. Andrew Martinez
  2. sqlalchemy


sqlalchemy / README.unittests.rst


SQLAlchemy unit tests by default run using Python's built-in sqlite3 module. If running on Python 2.4, pysqlite must be installed.

Unit tests are run using nose. Nose is available at:


SQLAlchemy implements a nose plugin that must be present when tests are run. This plugin is invoked when the test runner script provided with SQLAlchemy is used.

NOTE: - the nose plugin is no longer installed by setuptools as of version 0.7 ! Use "python setup.py test" or "./sqla_nose.py".


A plain vanilla run of all tests using sqlite can be run via setup.py:

$ python setup.py test

The -v flag also works here:

$ python setup.py test -v


To run all tests:

$ ./sqla_nose.py

If you're running the tests on Microsoft Windows, then there is an additional argument that must be passed to ./sqla_nose.py:

> ./sqla_nose.py --first-package-wins

This is required because nose's importer will normally evict a package from sys.modules if it sees a package with the same name in a different location. Setting this argument disables that behavior.

Assuming all tests pass, this is a very unexciting output. To make it more interesting:

$ ./sqla_nose.py -v


Any directory of test modules can be run at once by specifying the directory path:

$ ./sqla_nose.py test/dialect

Any test module can be run directly by specifying its module name:

$ ./sqla_nose.py test.orm.test_mapper

To run a specific test within the module, specify it as module:ClassName.methodname:

$ ./sqla_nose.py test.orm.test_mapper:MapperTest.test_utils


Help is available via --help:

$ ./sqla_nose.py --help

The --help screen is a combination of common nose options and options which the SQLAlchemy nose plugin adds. The most commonly SQLAlchemy-specific options used are '--db' and '--dburi'.


Tests will target an in-memory SQLite database by default. To test against another database, use the --dburi option with any standard SQLAlchemy URL:


Use an empty database and a database user with general DBA privileges. The test suite will be creating and dropping many tables and other DDL, and preexisting tables will interfere with the tests.

Several tests require alternate usernames or schemas to be present, which are used to test dotted-name access scenarios. On some databases such as Oracle or Sybase, these are usernames, and others such as Postgresql and MySQL they are schemas. The requirement applies to all backends except SQLite and Firebird. The names are:

test_schema_2 (only used on Postgresql)

Please refer to your vendor documentation for the proper syntax to create these namespaces - the database user must have permission to create and drop tables within these schemas. Its perfectly fine to run the test suite without these namespaces present, it only means that a handful of tests which expect them to be present will fail.

Additional steps specific to individual databases are as follows:

MYSQL: Default storage engine should be "MyISAM".   Tests that require
"InnoDB" as the engine will specify this explicitly.

ORACLE: a user named "test_schema" is created.

The primary database user needs to be able to create and drop tables,
synonyms, and constraints within the "test_schema" user.   For this
to work fully, including that the user has the "REFERENCES" role
in a remote schema for tables not yet defined (REFERENCES is per-table),
it is required that the test the user be present in the "DBA" role:

    grant dba to scott;

SYBASE: Similar to Oracle, "test_schema" is created as a user, and the
primary test user needs to have the "sa_role".

It's also recommended to turn on "trunc log on chkpt" and to use a
separate transaction log device - Sybase basically seizes up when
the transaction log is full otherwise.

A full series of setup assuming sa/master:

    disk init name="translog", physname="/opt/sybase/data/translog.dat", size="10M"
    create database sqlalchemy on default log on translog="10M"
    sp_dboption sqlalchemy, "trunc log on chkpt", true
    sp_addlogin scott, "tiger7"
    sp_addlogin test_schema, "tiger7"
    use sqlalchemy
    sp_adduser scott
    sp_adduser test_schema
    grant all to scott
    sp_role "grant", sa_role, scott

Sybase will still freeze for up to a minute when the log becomes
full.  To manually dump the log::

    dump tran sqlalchemy with truncate_only

MSSQL: Tests that involve multiple connections require Snapshot Isolation
ability implemented on the test database in order to prevent deadlocks that
will occur with record locking isolation. This feature is only available
with MSSQL 2005 and greater. You must enable snapshot isolation at the
database level and set the default cursor isolation with two SQL commands:



MSSQL+zxJDBC: Trying to run the unit tests on Windows against SQL Server
requires using a test.cfg configuration file as the cmd.exe shell won't
properly pass the URL arguments into the nose test runner.

If you'll be running the tests frequently, database aliases can save a lot of typing. The --dbs option lists the built-in aliases and their matching URLs:

$ ./sqla_nose.py --dbs
Available --db options (use --dburi to override)
           mysql    mysql://scott:tiger@
          oracle    oracle://scott:tiger@
        postgresql    postgresql://scott:tiger@

To run tests against an aliased database:

$ ./sqla_nose.py --db=postgresql

To customize the URLs with your own users or hostnames, create a file called test.cfg at the top level of the SQLAlchemy source distribution. This file is in Python config format, and contains a [db] section which lists out additional database configurations:


Your custom entries will override the defaults and you'll see them reflected in the output of --dbs.


SQLAlchemy logs its activity and debugging through Python's logging package. Any log target can be directed to the console with command line options, such as:

$ ./sqla_nose.py test.orm.unitofwork --log-info=sqlalchemy.orm.mapper \
  --log-debug=sqlalchemy.pool --log-info=sqlalchemy.engine

This would log mapper configuration, connection pool checkouts, and SQL statement execution.


Coverage is tracked using Nose's coverage plugin. See the nose documentation for details. Basic usage is:

$ ./sqla_nose.py test.sql.test_query --with-coverage

BIG COVERAGE TIP !!! There is an issue where existing .pyc files may store the incorrect filepaths, which will break the coverage system. If coverage numbers are coming out as low/zero, try deleting all .pyc files.


See the new file README.dialects.rst for detail on dialects.