Tempest - The OpenStack Integration Test Suite

This is a set of integration tests to be run against a live OpenStack cluster. Tempest has batteries of tests for OpenStack API validation, Scenarios, and other specific tests useful in validating an OpenStack deployment.

Design Principles

Tempest Design Principles that we strive to live by.

  • Tempest should be able to run against any OpenStack cloud, be it a one node devstack install, a 20 node lxc cloud, or a 1000 node kvm cloud.
  • Tempest should be explicit in testing features. It is easy to auto discover features of a cloud incorrectly, and give people an incorrect assessment of their cloud. Explicit is always better.
  • Tempest uses OpenStack public interfaces. Tests in Tempest should only touch public interfaces, API calls (native or 3rd party), public CLI or libraries.
  • Tempest should not touch private or implementation specific interfaces. This means not directly going to the database, not directly hitting the hypervisors, not testing extensions not included in the OpenStack base. If there is some feature of OpenStack that is not verifiable through standard interfaces, this should be considered a possible enhancement.
  • Tempest strives for complete coverage of the OpenStack API and common scenarios that demonstrate a working cloud.
  • Tempest drives load in an OpenStack cloud. By including a broad array of API and scenario tests Tempest can be reused in whole or in parts as load generation for an OpenStack cloud.
  • Tempest should attempt to clean up after itself, whenever possible we should tear down resources when done.
  • Tempest should be self testing.

Quickstart

To run Tempest, you first need to create a configuration file that will tell Tempest where to find the various OpenStack services and other testing behavior switches.

The easiest way to create a configuration file is to copy the sample one in the etc/ directory

$> cd $TEMPEST_ROOT_DIR
$> cp etc/tempest.conf.sample etc/tempest.conf

After that, open up the etc/tempest.conf file and edit the configuration variables to match valid data in your environment. This includes your Keystone endpoint, a valid user and credentials, and reference data to be used in testing.

Note

If you have a running devstack environment, tempest will be automatically configured and placed in /opt/stack/tempest. It will have a configuration file already set up to work with your devstack installation.

Tempest is not tied to any single test runner, but testr is the most commonly used tool. After setting up your configuration file, you can execute the set of Tempest tests by using testr

$> testr run --parallel

To run one single test

$> testr run --parallel tempest.api.compute.servers.test_servers_negative.ServersNegativeTestJSON.test_reboot_non_existent_server

Alternatively, you can use the run_tempest.sh script which will create a venv and run the tests or use tox to do the same.

Configuration

Detailed configuration of tempest is beyond the scope of this document. The etc/tempest.conf.sample attempts to be a self documenting version of the configuration.

The sample config file is auto generated using the script: tools/generate_sample.sh

The most important pieces that are needed are the user ids, openstack endpoints, and basic flavors and images needed to run tests.

Common Issues

Tempest was originally designed to primarily run against a full OpenStack deployment. Due to that focus, some issues may occur when running Tempest against devstack.

Running Tempest, especially in parallel, against a devstack instance may cause requests to be rate limited, which will cause unexpected failures. Given the number of requests Tempest can make against a cluster, rate limiting should be disabled for all test accounts.

Additionally, devstack only provides a single image which Nova can use. For the moment, the best solution is to provide the same image uuid for both image_ref and image_ref_alt. Tempest will skip tests as needed if it detects that both images are the same.

Unit Tests

Tempest also has a set of unit tests which test the tempest code itself. These tests can be run by specifing the test discovery path:

$> OS_TEST_PATH=./tempest/tests testr run --parallel

By setting OS_TEST_PATH to ./tempest/tests it specifies that test discover should only be run on the unit test directory. The default value of OS_TEST_PATH is OS_TEST_PATH=./tempest/test_discover which will only run test discover on the tempest suite.

Alternatively, you can use the run_tests.sh script which will create a venv and run the unit tests. There are also the py26, py27, or py33 tox jobs which will run the unit tests with the corresponding version of python.

Python 2.6

Tempest can be run with Python 2.6 however the unit tests and the gate currently only run with Python 2.7, so there are no guarantees about the state of tempest when running with Python 2.6. Additionally, to enable testr to work with tempest using python 2.6 the discover module from the unittest-ext project has to be patched to switch the unittest.TestSuite to use unittest2.TestSuite instead. See:

https://code.google.com/p/unittest-ext/issues/detail?id=79

Branchless Tempest Considerations

Starting with the OpenStack Icehouse release Tempest no longer has any stable branches. This is to better ensure API consistency between releases because the API behavior should not change between releases. This means that the stable branches are also gated by the Tempest master branch, which also means that proposed commits to Tempest must work against both the master and all the currently supported stable branches of the projects. As such there are a few special considerations that have to be accounted for when pushing new changes to tempest.

1. New Tests for new features

When adding tests for new features that were not in previous releases of the projects the new test has to be properly skipped with a feature flag. Whether this is just as simple as using the @test.requires_ext() decorator to check if the required extension (or discoverable optional API) is enabled or adding a new config option to the appropriate section. If there isn’t a method of selecting the new feature from the config file then there won’t be a mechanism to disable the test with older stable releases and the new test won’t be able to merge.

2. Bug fix on core project needing Tempest changes

When trying to land a bug fix which changes a tested API you’ll have to use the following procedure:

- Propose change to the project, get a +2 on the change even with failing
- Propose skip on Tempest which will only be approved after the
  corresponding change in the project has a +2 on change
- Land project change in master and all open stable branches (if required)
- Land changed test in Tempest

Otherwise the bug fix won’t be able to land in the project.

3. New Tests for existing features

If a test is being added for a feature that exists in all the current releases of the projects then the only concern is that the API behavior is the same across all the versions of the project being tested. If the behavior is not consistent the test will not be able to merge.

API Stability

For new tests being added to Tempest the assumption is that the API being tested is considered stable and adheres to the OpenStack API stability guidelines. If an API is still considered experimental or in development then it should not be tested by Tempest until it is considered stable.