Add doc for running functional test

Change-Id: I0bb1619435b5fb7cfcc4ea55691d728413939fef

doc/source/contributor/functional_test.rst

@@ -2,27 +2,94 @@
 How to run functional test
 ==========================
 
-Install DevStack
-----------------
-Functional test defined for Trove is supposed to be running against DevStack. It's recommended that the host on which the DevStack is running should support nested virtualization, otherwise errors or timeout may occur during the testing. Refer to https://docs.openstack.org/devstack/latest/guides/devstack-with-nested-kvm.html for how to check and enable nested virtualization on the host.
+For historical reasons, prior to Victoria, Trove was not using Tempest for running functional test. All the functional tests are organized using the Python library `Proboscis <https://pythonhosted.org/proboscis/>`_， which has not been maintained for a long time.
+
+However, Trove team is not going to migrate all the existing functional tests to `trove-tempest-plugin <https://github.com/openstack/trove-tempest-plugin>`_ due to lack of upstream maintainers, new functional tests should go with trove-tempest-plugin, new features shouldn't break the existing functional tests.
 
 .. note::
 
-    The functional test is different with Trove tempest test.
+   In this guide, "functional test" refers to the existing functional test cases in trove repo, "tempest test" refers to test cases in trove-tempest-plugin repo.
 
-See `Install Trove in DevStack <https://docs.openstack.org/trove/latest/install/install-devstack.html>`_ for details.
+Since Victoria, the upstream CI jobs keep failing because of the poor performance of the CI devstack host (virtual machine), trove project contributors should guarantee any proposed patch passes both the functional test and trove tempest test by themselves, the code reviewer may ask for the test result.
 
-Run tests
----------
+Install DevStack
+----------------
 
-For example, to run functional test with mysql datastore version 5.7.29, in trove source code directory, run:
+It's recommended that the DevStack host should support nested virtualization, otherwise errors or timeouts may occur during the testing. Refer to https://docs.openstack.org/devstack/latest/guides/devstack-with-nested-kvm.html for how to check and enable nested virtualization on the host.
+
+See `Install Trove in DevStack <https://docs.openstack.org/trove/latest/install/install-devstack.html>`_ for development environment installation.
+
+Run functional test
+-------------------
+
+Trove uses ``trovestack`` to run functional test. ``trovestack`` is responsible for:
+
+* Install necessary packages
+* Build and register guest image (if the image doesn't exist in Glance)
+* Register datastore and version
+* Prepare the test config file ``/etc/trove/test.conf``.
+* Create Nova flavors used for testing.
+* Trigger the actual functional tests.
+
+For example, to run functional test with MySQL datastore version 5.7.29, in trove source code directory, run:
 
 .. code-block:: console
 
-    ADMIN_PASSWORD=password \
-    SERVICE_PASSWORD=password \
-    tox -e trovestack gate-tests mysql mysql 5.7.29
+   ADMIN_PASSWORD=password SERVICE_PASSWORD=password \
+   tox -e trovestack gate-tests \
+   mysql \
+   mysql \
+   5.7.29
 
 * Parameters for ``gate-tests`` sub-command: ``<datastore_type> <test_group> <datastore_version>``. There are a few of test groups pre-defined: mysql, mysql-supported-single, mysql-supported-multi, mariadb-supported-single, mariadb-supported-multi, etc.
 * ``ADMIN_PASSWORD`` and ``SERVICE_PASSWORD`` are the passwords defined in the ``local.conf`` file in devstack directory.
-* By default, all the instances created during testing will be deleted automatically. For debugging purpose, if you want to keep the instances, you need to specify ``TESTS_DO_NOT_DELETE_INSTANCE=True``.
+* By default, all the instances created during testing will be deleted automatically. For debugging purposes, if you want to keep the instances, specify ``TESTS_DO_NOT_DELETE_INSTANCE=True``.
+
+Another example of running tests for MariaDB 10.4.13:
+
+.. code-block:: console
+
+   ADMIN_PASSWORD=password SERVICE_PASSWORD=password \
+   tox -e trovestack gate-tests \
+   mariadb \
+   mariadb-supported-single \
+   10.4.13
+
+Run tempest test
+----------------
+
+Trove tempest test can be running in the same way as other openstack tempest test. See `Tempest user guide <https://docs.openstack.org/tempest/latest/overview.html#quickstart>`_.
+
+Prepare tempest config for trove-tempest-plugin before running, an example config:
+
+.. code-block:: ini
+
+   [auth]
+   tempest_roles = ResellerAdmin
+
+   [network]
+   public_network_id = 48e5e576-ec48-4597-bfee-658e358f31a9
+
+   [database]
+   enabled_datastores=mysql
+   default_datastore_versions = mysql:5.7.30
+   pre_upgrade_datastore_versions = mysql:5.7.29
+   flavor_id = 28153197-6690-4485-9dbc-fc24489b0683
+   resize_flavor_id = d2
+   volume_type = lvmdriver-1
+   database_build_timeout = 1800
+   shared_network =
+
+Some example commands:
+
+#. List all the MySQL related test cases:
+
+   .. code-block:: console
+
+      tempest run --list-tests --regex ^trove_tempest_plugin | grep -i mysql | sort
+
+#. Run one single test:
+
+   .. code-block:: console
+
+      tempest run --concurrency 1 --regex ^trove_tempest_plugin.tests.scenario.test_replication.TestReplicationMySQL.test_replication