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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.

Factories

GitLab uses factory_girl as a test fixture replacement.

  • Factory definitions live in spec/factories/, named using the pluralization of their corresponding model (User factories are defined in users.rb).
  • 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 should) call create(...) instead of FactoryGirl.create(...).
  • 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 ActiveRecord objects. See example.

JavaScript

GitLab uses Teaspoon to run its Jasmine JavaScript specs. They can be run on the command line via bundle exec teaspoon, or via a web browser at http://localhost:3000/teaspoon when the Rails server is running.

  • JavaScript tests live in spec/javascripts/, matching the folder structure of app/assets/javascripts/: app/assets/javascripts/behaviors/autosize.js.coffee has a corresponding spec/javascripts/behaviors/autosize_spec.js.coffee file.

  • Haml fixtures required for JavaScript tests live in spec/javascripts/fixtures. They should contain the bare minimum amount of markup necessary for the test.

    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.

RSpec

General Guidelines

  • Use a single, top-level describe ClassName block.
  • Use described_class instead of repeating the class name being described.
  • Use .method to describe class methods and #method to describe instance methods.
  • Use context to test branching logic.
  • Don't describe symbols (see Gotchas).
  • Don't supply the :each argument to hooks since it's the default.
  • Prefer not_to to 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.

let variables

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:

  • let variables are preferable to instance variables. Local variables are preferable to let variables.
  • Use let to reduce duplication throughout an entire spec file.
  • Don't use let to define variables used by a single test; define them as local variables inside the test's it block.
  • Don't define a let variable inside the top-level describe block that's only used in a more deeply-nested context or describe block. Keep the definition as close as possible to where it's used.
  • Try to avoid overriding the definition of one let variable with another.
  • Don't define a let variable that's only used by the definition of another. Use a helper method instead.

Test speed

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:

  • double and spy are faster than FactoryGirl.build(...)
  • FactoryGirl.build(...) and .build_stubbed are faster than .create.
  • Don't create an object when build, build_stubbed, attributes_for, spy, or double will do. Database persistence is slow!
  • Use create(:empty_project) instead of create(:project) when you don't need the underlying Git repository. Filesystem operations are slow!
  • Don't mark a feature as requiring JavaScript (through @javascript in Spinach or js: true in 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 user_changes_password_spec.rb.
  • Use only one feature block 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.

As of March 2016, we are trying to avoid adding new Spinach tests going forward, opting for RSpec feature specs.

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.

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