[jest/expect-expect] doesn't work with assertion function names with $ character

Problem

I have configured jest/expect-expect the next way:

"jest/expect-expect": ["warn", { "assertFunctionNames": ["expect", "expect$"] }]

But as I explored the rule doesn’t work with the function names which contain special characters from regular expressions, including $.

As I see from the implementation of matching function provided in assertFunctionNames patterns are transformed into regular expressions for further matching. Thus, characters as $ are handled as regex special characters, not like part of a provided function name.

Expectation

I expect that assertion function names with special characters are whitelisted and do not trigger eslint errors.

Proposed solution

As a solution, I propose to add an extra step and escape special characters while converting provided function name into regular expression.

function matchesAssertFunctionName(
  nodeName: string,
  patterns: readonly string[],
): boolean {
  return patterns.some(p =>
    new RegExp(
      `^${p
        .split('.')
        .replace((/[+?^${}()|[\]\\]/g, '\\$&'))
        .map(x => {
          if (x === '**') return '[a-z\\.]*';

          return x.replace(/\*/gu, '[a-z]*');
        })
        .join('\\.')}(\\.|$)`,
      'ui',
    ).test(nodeName),
  );
}

NOTE: the link to syntax characters list. I’ve excluded *, . as they could be used in wildcards syntax of names.

[nsasinovich]

Thank you!

[G-Rath]

No problem 😃

You’re totally right that it’ll be good to have an example for this - I’ve done so via #627, and also added a test to ensure we support this situation.