How can I migrate bad mocking practices?

[jhage-snapsheet]

Hello,

I am trying to migrate a very large project from jest to rstest. We have thousands of files that do something like:
services/__mocks__/index.js:

class MockApiClient extends ApiClient {
  fetch = rstest.fn().mockResolvedValue({ json: () => Promise.resolve({ data: [] }) })
}
export const mockApiClient = new MockApiClient({ baseDomain: 'https://example.com' });

example.test.js:

import * as mockApiFile from '../../services';
mockApiFile.mockApiClient.fetch.mockResolvedValue()

The problem is rspack finds that mockApiClient does NOT exist in the real services/index.js, which is correct, but it does exist in the mock:

ESModulesLinkingError: export 'mockApiClient' (imported as 'mockApiFile') was not found in '../../services' (possible exports...

I understand this is a bad practice on our end, but, I can't migrate thousands of files that break this rule

Any suggestions? I essentially need setup-files and it's global rstest.mock to run BEFORE compilation, or maybe some kind of plugin to run at comp time. Not sure if this is possible or if we are SOL.

Thank you,
Jeff

[9aoy]

In addition to compilation errors, can the test run as expected? Is the mock officially effective?
If it's just an ESModulesLinkingError and doesn't affect actual execution, I think it's related to rstest(rspack) compiling the code beforehand. I can disable these errors in rstest.

[jhage-snapsheet]

Yes, the mock works. It is just an EsModulesLinkingError. I have a repro with:

• Passing in jest 👍
• Complation fail in rstest (rspack) 👎
• Passing in rstest if I use rspack plugin to change the import to refer to the mock at compile time 👍

[jhage-snapsheet]

Thank you