[Bug]: Declaration of TestComponent with signal input breaks jest.mock

[MillerSvt]

Version

14.1.0

Steps to reproduce

1. clone https://github.com/MillerSvt/jest-preset-angular-bug-repro
2. run npm i
3. run nx test app

Expected behavior

Test pass, jest.mock works in test-with-input.spec.ts

Actual behavior

jest.mock not works in test-with-input.spec.ts. Test fails.

Additional context

Temporary workaround

Declare TestComponent in separate file.

Environment

Need to install the following packages:
envinfo@7.13.0
Ok to proceed? (y) y

  System:
    OS: macOS 14.5
    CPU: (10) arm64 Apple M1 Pro
  Binaries:
    Node: 20.12.2 - ~/.nvm/versions/node/v20.12.2/bin/node
    Yarn: 1.22.22 - ~/.nvm/versions/node/v20.12.2/bin/yarn
    npm: 10.5.0 - ~/.nvm/versions/node/v20.12.2/bin/npm
  npmPackages:
    jest: ^29.4.1 => 29.7.0

[ahnpnl]

Seems like the issue is related to hoisting with jest.mock. The hoisting is done via ts-jest

[MillerSvt]

Is there a link to the issue in ts-jest?

And I can't understand why it works without signal input if the problem is ts-jest...

[ahnpnl]

No there are any issues opened yet in ts-jest.

We transform codes using ts-jest behind the scene, which also includes hoisting for jest object. I think this hoisting doesn't work anymore when the component with input signal is in the same file with jest object. Possibly that input signal introduces something which affects hoisting logic

[MillerSvt]

No there are any issues opened yet in ts-jest.

Should I open an issue?

[ahnpnl]

I digged a bit more. So the transformed code looks a bit like this

const some_utility_fn_1 = tslib_1.__importDefault(require("./some-utility-fn"));
const i0 = tslib_1.__importStar(require("@angular/core"));
jest.mock('./some-utility-fn');

Here we can see clearly that because of tslib_1.__importDefault helper which prevents jest.mock to be hoisted.

Setting importHelper: false in tsconfig.spec.json won't help either because there will be always an import helper created

const some_utility_fn_1 = __importDefault(require("./some-utility-fn"));
const i0 = __importStar(require("@angular/core"));
jest.mock('./some-utility-fn');

With this information, I think it's sufficient enough to create an issue for ts-jest