typelevel / typelevel/cats

Add guideline for redundant tests

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#2,919 2 comments 0 reactions 0 assignees View on GitHub

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Dominant language
Scala
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Description

Laws for type class inherited from a parent type class also includes laws for the parent type class. Thus when testing an instance it's redundant to test laws for both type classes.
The current code base is not consistent in regards to this redundancy. We need to come up with a principle and add to the guideline.

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by locating the existing testing guideline and reviewing the inconsistent law tests in the Cats codebase. Determine a principle for handling inherited type-class laws, then document it in the guideline; done means the rule is explicit and addresses the reported redundancy.

Written by the indexing model from the issue text.

Assessment

Tech stack
scala
Domain
documentation, testing
Issue type
Documentation
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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