Testing Standards and Style Guidelines
This guide outlines standards and best practices for automated testing of GitLab CE and EE.
It is meant to be an extension of the thoughtbot testing styleguide. If this guide defines a rule that contradicts the thoughtbot guide, this guide takes precedence. Some guidelines may be repeated verbatim to stress their importance.
GitLab uses factory_girl as a test fixture replacement.
- Factory definitions live in
spec/factories/, named using the pluralization of their corresponding model (
Userfactories are defined in
- There should be only one top-level factory definition per file.
- FactoryGirl methods are mixed in to all RSpec groups. This means you can (and
- Make use of traits to clean up definitions and usages.
- When defining a factory, don't define attributes that are not required for the resulting record to pass validation.
- When instantiating from a factory, don't supply attributes that aren't required by the test.
- Factories don't have to be limited to
ActiveRecordobjects. See example.
the command line via
bundle exec teaspoon, or via a web browser at
http://localhost:3000/teaspoon when the Rails server is running.
Warning: Keep in mind that a Rails view may change and invalidate your test, but everything will still pass because your fixture doesn't reflect the latest view.
Keep in mind that in a CI environment, these tests are run in a headless browser and you will not have access to certain APIs, such as
Notification, which will have to be stubbed.
- Use a single, top-level
described_classinstead of repeating the class name being described.
.methodto describe class methods and
#methodto describe instance methods.
contextto test branching logic.
describesymbols (see Gotchas).
- Don't supply the
:eachargument to hooks since it's the default.
to_not(this is enforced by Rubocop).
- Try to match the ordering of tests to the ordering within the class.
- Try to follow the Four-Phase Test pattern, using newlines to separate phases.
GitLab's RSpec suite has made extensive use of
let variables to reduce
duplication. However, this sometimes comes at the cost of clarity,
so we need to set some guidelines for their use going forward:
letvariables are preferable to instance variables. Local variables are preferable to
letto reduce duplication throughout an entire spec file.
- Don't use
letto define variables used by a single test; define them as local variables inside the test's
- Don't define a
letvariable inside the top-level
describeblock that's only used in a more deeply-nested
describeblock. Keep the definition as close as possible to where it's used.
- Try to avoid overriding the definition of one
letvariable with another.
- Don't define a
letvariable that's only used by the definition of another. Use a helper method instead.
GitLab has a massive test suite that, without parallelization, can take more than an hour to run. It's important that we make an effort to write tests that are accurate and effective as well as fast.
Here are some things to keep in mind regarding test performance:
spyare faster than
.build_stubbedare faster than
createan object when
doublewill do. Database persistence is slow!
create(:project)when you don't need the underlying Git repository. Filesystem operations are slow!
js: truein RSpec) unless it's actually required for the test to be valid. Headless browser testing is slow!
Features / Integration
- Feature specs live in
spec/features/and should be named
ROLE_ACTION_spec.rb, such as
- Use only one
featureblock per feature spec file.
- Use scenario titles that describe the success and failure paths.
- Avoid scenario titles that add no information, such as "successfully."
- Avoid scenario titles that repeat the feature title.
Spinach (feature) tests
GitLab moved from Cucumber to Spinach for its feature/integration tests in September 2012.
Adding new Spinach scenarios is acceptable only if the new scenario requires
no more than one new
step definition. If more than that is required, the
test should be re-implemented using RSpec instead.