fix(jest-mock): improved `MockedClass` type

[k-rajat19]

Summary

Fixes #14458

added constructor signature in MockedClass type so that it returns mocked Instance (of type Mocked<InstanceType<typeof original class>>) instead of returning the instance typed with original class type.

Test plan

Tests added

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[SimenB]

This is failing type tests in packages/jest-types/__typetests__/jest.test.ts

[k-rajat19]

I have run build command multiple times and also see the updated types in build folder,but still all type tests are passing in my local. After looking at CI failure I found that tests which are using Class.prototype are failing but they are supposed to be passed as MockedObject<T> will provide all typings for the prototype object in a Class.

export type MockedClass<T extends ClassLike> = MockInstance<
  (...args: ConstructorParameters<T>) => Mocked<InstanceType<T>>
 > &
  (new (...args: ConstructorParameters<T>) => Mocked<InstanceType<T>>) &
+ MockedObject<T>;

[mrazauskas]

The type test is failing in CI when using TypeScript 5.0. Locally you can run yarn test-types --target 5.0 to see the same error.

This change is working without issues from Typescript 5.4 and up. You can check this with: yarn test-types --target 5.4,5.5

[mrazauskas]

An easy solution could be to set the lowest supported TypeScript version to 5.4. If @SimenB agrees (;

Otherwise the way forward would be make [email protected] work as well. If that helps, it is possible to use bisect from every-ts with TSTyche to find out which exact comment to TypeScript repo makes this implementation work. (Just for fun, I will try to do this a bit later. Too busy at the moment.)

[SimenB]

I'd be down with increasing to 5.2 or something if it'd help, but not 5.4

[k-rajat19]

tests are failing with 5.2, we can hold this PR till jest upgrades ts to 5.4

Otherwise the way forward would be make [email protected] work as well. If that helps, it is possible to use bisect from every-ts with TSTyche to find out which exact comment to TypeScript repo makes this implementation work. (Just for fun, I will try to do this a bit later. Too busy at the moment.)

Or may be try this ...

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