diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index a6a308c4..024bfc21 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -19,3 +19,42 @@ Pull requests submitted through GitHub will be ignored.
 Bugs should be filed on Launchpad, not GitHub:
 
    https://bugs.launchpad.net/oslo.db
+
+
+How to run unit tests
+=====================
+
+oslo.db (as all OpenStack projects) uses tox to run unit tests. You can find
+general information about OpenStack unit tests and testing with tox in wiki_.
+
+oslo.db tests use MySQL-python as the default MySQL DB API driver (which is
+true for OpenStack), and psycopg2 for PostgreSQL. pip will build these libs in
+your venv, so you must ensure that you have the required system packages
+installed.  For Ubuntu/Debian they are python-dev, libmysqlclient-dev and
+libpq-dev.  For Fedora/CentOS - gcc, python-devel, postgresql-devel and
+mysql-devel.
+
+The oslo.db unit tests system allows to run unittests on real databases. At the
+moment it supports MySQL, PostgreSQL and SQLite.
+For testing on a real database backend you need to set up a user
+``openstack_citest`` with password ``openstack_citest`` on localhost (some
+OpenStack projects require a database named 'openstack_citest' too).
+Please note, that this user must have permissions to create and drop databases.
+If the testing system is not able to connect to the backend, tests on it will
+be skipped.
+
+For PostgreSQL on Ubuntu you can create a user in the following way::
+
+ sudo -u postgres psql
+ postgres=# create user openstack_citest with createdb login password
+            'openstack_citest';
+
+For MySQL you can use the following commands::
+
+ mysql -u root
+ mysql> CREATE USER 'openstack_citest'@'localhost' IDENTIFIED BY
+        'openstack_citest';
+ mysql> GRANT ALL PRIVILEGES ON * . * TO 'openstack_citest'@'localhost';
+ mysql> FLUSH PRIVILEGES;
+
+.. _wiki: https://wiki.openstack.org/wiki/Testing#Unit_Tests