[Feature]: do not evaluate target module to infer its shape for auto-mock

[escaton]

What problem does this feature solve?

Allow auto-mocking modules that cannot be safely evaluated, e.g access browsers globals in module root.
Although, it can be fixed with proper testEnvironment, it is a compromise and also Vitest seems to solve it properly.

What does the proposed API look like?

No API change, just allow to rs.mock('I-will-call-DOM-immediately', {mock: true}) without evaluating it.

[9aoy]

@escaton We did some verification on the Vitest side. Based on our testing, Vitest also evaluates the original module to infer its export shape during auto-mock (i.e. when no factory function and no __mocks__ file is provided).

Could you provide a concrete Vitest example where this works as you described? That would help us better understand the specific behavior you're expecting and whether there's a particular Vitest configuration or pattern that avoids the evaluation. Thanks!

[escaton]

You are right, the difference is not in the evaluation, but in laziness. In my test I do mock the library (vue3-lottie@3.3.1) but the test path does not reach the import('vue3-lottie'), and vitest shows no error, but rstest tries to mock it eagerly and fails.

[9aoy]

This issue sounds similar to one we’ve fixed before. You can try upgrading rstest to v0.8.3 or later. If the problem still persists after upgrading, please provide a minimal reproduction demo.

#745