mocha-avoid-only only checking for string literals

[mmilleruva]

I noticed mochaAvoidOnlyRule.ts was missing cases where the first argument was not a string literal. So the following case would be missed:

['x', 'y', 'z'].forEach((val) =>  {
   describe.only(val, () => { ...}) 
})

I saw that there were test cases specifically written not to catch this case. I believe it is to avoid false positives where .only is not from mocha. It might be better to be more aggressive with reporting the issue and people can use https://palantir.github.io/tslint/usage/rule-flags/ to disable false positives.

Perhaps the best approach would be to make this rule a typed rule and check if the return of .only is one of ExclusiveSuiteFunction or ExclusiveTestFunction

https://github.com/DefinitelyTyped/DefinitelyTyped/blob/master/types/mocha/index.d.ts#L392

[JoshuaKGoldberg]

+1 to using type information to fix this false negative! Having it as an optionally typed rule would be best so we still get the existing behavior if no project is provided.

[reduckted]

Another case where you can get a false negative is Angular unit tests that use fakeAsync. The code looks like this:

it.only('something', fakeAsync(() => {
}));

Because the second parameter isn't an arrow function, the rule doesn't consider it to be mocha's it.only() function. Making the rule typed would fix this.

[JoshuaKGoldberg]

☠️ It's time! ☠️

Per #876, this repository is no longer accepting feature pull requests. TSLint is being deprecated and we recommend you switch to https://typescript-eslint.io.

Thanks for open sourcing with us, everyone!