[Feature]: Add `it` modifier for run test inside injection context

[MillerSvt]

🚀 Feature Proposal

Currently if we need run many tests inside injection context, we should wrap each test in TestBed.runInInjectionContext function. It works, but not useful.

I propose to create it.injectable modifier to run tests inside injection context.

It can be opt in if needed.

Motivation

jest-preset-angular is useful tool for testing angular projects. If we create possibility to cre

Possible solution

declare global {
	namespace jest {
		interface It {
			injectable: (
				name: string,
				fn: (() => void) | (() => PromiseLike<unknown>),
				timeout?: number,
			) => void;
		}
	}
}

it.injectable = (
	name: string,
	fn: (() => void) | (() => PromiseLike<unknown>),
	timeout?: number,
) => {
	it(name, () => TestBed.runInInjectionContext(fn), timeout);
};

it.only.injectable = (
	name: string,
	fn: (() => void) | (() => PromiseLike<unknown>),
	timeout?: number,
) => {
	it.only(name, () => TestBed.runInInjectionContext(fn), timeout);
};

it.skip.injectable = (
	name: string,
	fn: (() => void) | (() => PromiseLike<unknown>),
	timeout?: number,
) => {
	it.skip(name, () => TestBed.runInInjectionContext(fn), timeout);
};

it.concurrent.injectable = (
	name: string,
	fn: (() => void) | (() => PromiseLike<unknown>),
	timeout?: number,
) => {
	it.concurrent(name, () => TestBed.runInInjectionContext(fn), timeout);
};

it.concurrent.only.injectable = (
	name: string,
	fn: (() => void) | (() => PromiseLike<unknown>),
	timeout?: number,
) => {
	it.concurrent.only(name, () => TestBed.runInInjectionContext(fn), timeout);
};

it.concurrent.skip.injectable = (
	name: string,
	fn: (() => void) | (() => PromiseLike<unknown>),
	timeout?: number,
) => {
	it.concurrent.skip(name, () => TestBed.runInInjectionContext(fn), timeout);
};

Usage

it.injectable('should be correct value', () => {
	const value = inject(VALUE_TOKEN);

	expect(value).toEqual(testValue);
});

Real world example: ngxtension/ngxtension-platform#593

Additional

I can create pr with that

[ahnpnl]

I actually would prefer using “test context” pattern similar to Playwright or Vitest. That would keep the original framework APIs as is to reduce maintenance efforts and avoid breaking changes from test framework.

Also in this case, runInInjectionContext already implies that it is related to context.

You can check examples from Playwright https://playwright.dev/docs/browser-contexts#how-playwright-achieves-test-isolation or Vitest https://vitest.dev/guide/test-context

[MillerSvt]

Are there any examples of using this pattern in jest?

[ahnpnl]

I think I’ve seen this request for api for Jest some times ago but can’t remember. It’s definitely something very useful to work with in the long run for Jest with the popularity of Vitest and Playwright these days