chore: use TSTyche assertions in the document type test

[mrazauskas]

Summary

Same as #16067, but with some mismatch of expected types. Therefore, I think this needs an extra attention (see inline comments).

[mrazauskas]

Model<unknown> does not pass. The type seems to be plain unknown. Is that correct?

[vkarpov15]

Probably some type widening quirk - $model uses generics. I think we could just expect assignable here, or test const model: Model<unknown> = this.$model('Item1'), what do you think? I don't like expecting that the type is strictly unknown here

[mrazauskas]

typeof User or simply .type.toBe(User) does not pass. The type seems to be plain unknown. Is that correct?

[vkarpov15]

Similar type widening. Maybe we just check assignability?

[mrazauskas]

@vkarpov15 Thanks for feedback.

I took a better look and found out the following. The argument of expect() is typed as unknown and both Document#$model() and Document#model() methods do not type argument constraints. Looks like TypeScript decides to pass unknown as type argument (since that is allowed). The resulting type becomes unknown.

Two possible solutions:

1. Move the function call outside of the expect:

   const x = this.$model('Item1');
   expect(x).type.toBe<Model<unknown>>(); // pass

2. Or add constraints to both signatures and the resulting type will be inferred correctly. See fix: add type constraints for Document#model() #16081

What sounds better for you?

---

Another detail. Right now ReturnType<typeof this.$model> is inferred as unknown. After adding the constraints (as suggested in #16081) it becomes Model<DocType> (the return type of last overload).

I try to show that other unrelated APIs infer the unknown as well. TSTyche does not use ReturnType anyhow.

[vkarpov15]

I merged #16081

[mrazauskas]

I merged #16081

Thanks! Seems like all is working as expect. The unknowns are gone. See updated tests in d5cfb0a