Discourage use of :nocov: code comment

Problem

The use of Simplecov's # :nocov: (see docs) code comment excludes code from the coverage report.

Currently, there are 31 instances of # :nocov::

Click to expand

• # :nocov: the class including this concern is expected to test this method.
• # :nocov:
• # :nocov: the class including this concern is expected to test this method.
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov: Tested on subclasses.
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:
• # :nocov:

Proposed solution

As mentioned by @tkuah using # :nocov: "skews the percentage % of this Performance Indicator (https://about.gitlab.com/handbook/engineering/development/performance-indicators/#backend-unit-test-coverage)".

Any code should be covered by tests/specs. For this reason we should:

• Mention ban of :nocov: in development guidelines
• Add a 👮 rule to flag its use - !92671 (merged)

Refs

!92393 (comment 1028806103)

@tkuah: I think we should discourage :nocov: as it skews the percentage % of this Performance Indicator (https://about.gitlab.com/handbook/engineering/development/performance-indicators/#backend-unit-test-coverage).