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author | Robert Speicher <rspeicher@gmail.com> | 2016-04-02 03:30:24 +0300 |
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committer | Robert Speicher <rspeicher@gmail.com> | 2016-04-02 03:31:16 +0300 |
commit | 2e83b562030e078ce6d37f81915590426a57c820 (patch) | |
tree | aa9722a8b63f7aa1adbf9e09c67a2723cd6d36dd /doc/development/testing.md | |
parent | 60f4081e135bdcd893d60192e652c4b829c656dd (diff) |
Add a section about `let` to the Testing guide
[ci skip]
Diffstat (limited to 'doc/development/testing.md')
-rw-r--r-- | doc/development/testing.md | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/doc/development/testing.md b/doc/development/testing.md index 3d1c4ccab47..187d852e533 100644 --- a/doc/development/testing.md +++ b/doc/development/testing.md @@ -11,8 +11,7 @@ importance. ## Factories -GitLab uses [factory_girl] as a test -fixture replacement. +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`). @@ -65,8 +64,30 @@ the command line via `bundle exec teaspoon`, or via a web browser at - Don't `describe` symbols (see [Gotchas](gotchas.md#dont-describe-symbols)). - Prefer `not_to` to `to_not`. - Try to match the ordering of tests to the ordering within the class. -- Try to follow the [Four-Phase Test](https://robots.thoughtbot.com/four-phase-test) - pattern, using newlines to separate phases. +- Try to follow the [Four-Phase Test][four-phase-test] pattern, using newlines + to separate phases. + +[four-phase-test]: https://robots.thoughtbot.com/four-phase-test + +### `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][lets-not], +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. + +[lets-not]: https://robots.thoughtbot.com/lets-not ### Test speed |