Disallow the use of `only` in mocha tests

[owennicol]

Could we add in a rule for not allowing only in mocha tests please?

This is an ESLint plugin for the same thing if that helps: https://www.npmjs.com/package/eslint-plugin-mocha-no-only

[LinusU]

Would personally love this, too easy to accidentally commit this 😄

[Flet]

This is neat! However, I'd be a little worried that this could open the door to adding lots of framework/library specific rules, which could get hairy.

[LinusU]

Yeah, that is very true, might be a good idea to think about where to draw the line, and this could potentially be on the wrong side of that line :)

Although mocha is very widely used...

[ematipico]

.only is also support by Jest and AVA

[dcousens]

Useful, but I don't know if this should be standard's responsibility...

[blgm]

The best way that I've found to avoid committing .onlys is to use code coverage measurement and enforcement. Then if you accidentally try and commit a .only the CI will fail.

Jasmine uses xit instead of .only and it would be odd to add checks for Mocha but not Jasmine.

[feross]

I don't think this belongs in standard at this time. I have an idea that might accommodate additional rules for particular frameworks and I'd like to re-examine this rule if/when that becomes a thing.

[Janpot]

If I recall correctly, mocha has a --forbid-only flag. I think this is the right place for this functionality, not in standard.