@std/expect - export symbols required for matcher definition

[yannduperis]

Is your feature request related to a problem? Please describe.

I am developing a small library containing testing utilities.
I would like this library to provide an extended expect(), as documented for expect.extend() (which is a great functionality BTW).
I would prefer defining my matchers in individual files and import them (exactly like @std/expect does).

The problem is that I cannot type the context argument because MatcherContext is not part of the package named exports.

Therefore, I cannot write a matcher like that:

export function toHaveSignature(context: MatcherContext, signatureExpr: string) {
   // ...
}

Describe the solution you'd like

I'd like to be able to import MatcherContext from one of the package's entrypoints.

import { MatcherContext  } from "@std/expect";

Or even, if you want to keep the symbol footprint minimal for entrypoint designed for most users, to have a specific entrypoint for users who also need extra symbols for extension:

import { MatcherContext  } from "@std/expect/extend";

or

import { MatcherContext  } from "@std/expect/types";

I guess I could make the necessary changes, this is not especially difficult once agreement has been reached.

Describe alternatives you've considered

• Just write the matchers in a single file (which, honestly, would be fine for quite some time)
• Recreate the missing types (i.e. curl https://raw.githubusercontent.com/denoland/std/refs/heads/main/expect/_types.ts > std_expect.types.ts) and keep them in sync when there is a change.