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| -rw-r--r-- | doc/development/testing_guide/best_practices.md | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/doc/development/testing_guide/best_practices.md b/doc/development/testing_guide/best_practices.md index acbfa1850b4..e124a768c2e 100644 --- a/doc/development/testing_guide/best_practices.md +++ b/doc/development/testing_guide/best_practices.md @@ -158,12 +158,13 @@ instead of 30+ seconds in case of a regular `spec_helper`. ### `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], +GitLab's RSpec suite has made extensive use of `let`(along with it strict, non-lazy +version `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. +- `let!` variables are preferable to instance variables. `let` variables + are preferable to `let!` 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. @@ -173,6 +174,9 @@ so we need to set some guidelines for their use going forward: - 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. +- `let!` variables should be used only in case if strict evaluation with defined + order is required, otherwise `let` will suffice. Remember that `let` is lazy and won't + be evaluated until it is referenced. [lets-not]: https://robots.thoughtbot.com/lets-not |