Allow "on" keyword in RSpec/ContextWording

[D4uS1]

Hey guys,

in my opinion it would be nice to allow the "on" keyword for contexts in the RSpec/ContextWording cop.
This would be especially nice to test rails hooks that works "on update" or "on create" or "on destroy".

But i guess this is some matter of oppinion, hence i started this discussion.

What do you think about this?

[pirj]

Hey!

I'll separate in topics.

Configurable

The Community RSpec Style Guide is quite flexible in this regard:

A typical description will be an adjunct phrase starting with 'when', 'with', 'without', or similar words

The rubocop-rspec's default config has those three:

  Prefixes:
    - when
    - with
    - without

but you are encouraged to reconfigure that in your project or company-wide RuboCop settings to meet your style.

Popularity

A 3 y.o. research indicated the following frecency of prefix use:

• when 23760
• with 8150
• for 2090
• and 1993
• as 1204
• without 1035
• in 719
• user 688
• on 509
• if 482

Things might have changed since then. But still, "on" was far from the top of the list.

context vs describe

It's subjective, and is my personal opinion.
There is a subtle difference between semantics of context and describe, even though they are technically just aliases of example_group.
context is generally used when grouping examples contextually (e.g. "with xyz", "when xyz" or "if xyz"). I may have understood the meaning of "on update"/"on create" mistakenly, but it appears to me that those example groups consist of examples that are grouped not by the context (similar setup), but by what they test. In such a case, a describe might be a better way of grouping them. Please correct me if I'm mistaken with this hypothesis.