Tom Mrazauskas

Do you have `@types/jest` package installed?

Ah.. Might be you have, but it is not included in the `"types"` list (i.e. not visible for TypeScript): ```diff { "compilerOptions": { - "types": ["node"] + "types": ["jest", "node"]...

There is an alternative to explicitly declared `"types"`. You can declare `jest-expect-message` as an `@types/*` package in `package.json`: ```json { "devDependencies": { "@types/jest-expect-message": "npm:jest-expect-message@*", } } ``` Run `yarn install`...

> As this feature is not available there, is it sensible to skip the tests there? Yes. Usually tests are skipped, if some feature is not supported. The `onNodeVersions()` helper...

This looks interesting. I checked out this branch quickly with: ```ts expectTypeOf().toEqualTypeOf() // not allowed expectTypeOf().toMatchTypeOf() // not allowed expectTypeOf().toEqualTypeOf() // fail expectTypeOf().toMatchTypeOf() // pass !!! expectTypeOf().toEqualTypeOf() // fail expectTypeOf().toMatchTypeOf()...

@jcw- Do I get right that [jest-a-coverage-slip-detector](https://github.com/GetJobber/jest-a-coverage-slip-detector) is the solution to this problem?

> is not even looked at by you or others? Can you proof that?

> 1. Create a new project that uses a jest transformer (e.g. `ts-jest`). Is the `babel-jest` transformer causing this problem as well? I am asking this because `babel-jest` is the...

Does not reproduce with `babel-jest`. For me it errors loud and clear. The exit code is `1`. So this is either setup issue or a problem in a transformer you...

> It works but not when executed within `vm` part of node. So using [`jest-light-runner`](https://github.com/nicolo-ribaudo/jest-light-runner) could be a solution, right? Reference: https://github.com/facebook/jest/issues/2549#issuecomment-1098071474