Testing framework

Today we would like to share with you one of our recent subprojects. It is our testing framework. We have used to automate our tests for OpenStack with Lettuce. However we found that we need more features to build robust framework with it. So we created a Bunch tool. The main reason for Bunch was the motivation to write more flexible and powerful tests with Lettuce. Key points to improve were:

  • Avoid hardcoded values in test scenarios. Lettuce offers the only way for data-driven scenarios. This is done via scenario outlines. What means that all data is stored in script itself. External data sources may be only supported by your own test code. We may fill that gap introducing Jinja2 templates and YAML configuration files. Feature templates stay readable but gain flexibility. The regular Lettuce scripts are generated on every test execution thus saving BDD style. Stories remain comprehensible for an end-user.
  • Write test fixtures explicitly. It should be possible to write setup and teardown BDD stories. It is also important to have behavior specifications for installation procedures.
  • Share and re-use test fixtures, specify that test depends on specific fixtures Tests should be self-suffucient and should not rely on the state created by other tests. However it is often a huge overhead when each test performs its own setup which may always be the same. It is required to provide the concept of “dependencies” between tests and test fixtures.
  • Tests are environment agnostic but test fixtures are environment dependent. We may enable writing environment agnostic tests by moving all environment specific action into test fixtures. Thus test fixtures may have multiple versions aimed for different environments.

So we gathered these requirements and planned the following features for implementation:

  1. Support for scenario templates. Scenarios become parameterizable and do not loose BDD spirit. Foreign Lettuce scenarios can be adopted by replacing hardcoded values with template variables. (YAML and Jinja2 were used for that)
  2. Explicit separation of test fixtures from tests (setup, teardown and test scripts). Test scenario should not contain any actions that are specific to platform/configuration and should only perform actions on the product under test.
  3. Dependency specification for setup/teardown fixtures and sharing fixtures among tests.  Most of tests rely on the same state while other may have specific prerequisites.
  4. Parallel test execution. This is often required for long running end-to-end scenarios. That feature introduces a requirement that which are planned to be executed in parallel should be independent from each other and does not use the same resources.

Points 1-3 are implemented now. That should be enough to start using it.  However there is a plenty of stuff planned on the road-map.

We also shared our OpenStack test suite which runs within our CI workflow. So you may have a look how Bunch works. Links to tool, doc and tests are below:

Just install Bunch, check out tests, adjust config.yaml and execute:
bunch -e clean openstack-core-test/smoketests/basic/ <resultdir>

Both Bunch and tests are under active development, so there are not much tests in the repo. This is just the beginning. Stay tuned.

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