Summary

The runtime code modification and integration test case is added in Rstest repository web-infra-dev/rstest#389.

This PR is to resolve two main issues in Rstest mock side:

1. Issue: mock hoist order conflict: if the mock for ../src/c is hoisted to a position that is too top, the mock factory in ../src/c will access an uninitialized (undefined) rs object.

   Solution: When a mock factory exists, hoist .mock to the placeholder by using InitFragmentStage::StageAsyncESMImports and set its position to the maximum. Additionally, add the line var _src_c__WEBPACK_IMPORTED_MODULE_1__ = __webpack_require__("./mock/src/c.ts"); to refresh the reference to _src_c__WEBPACK_IMPORTED_MODULE_1__.

   import { expect, it, rs } from '@rstest/core';
   import { c } from '../src/c';
   import { d } from '../src/d';
   
   // To test async mocking factory.
   rs.mock('../src/c', async () => {
     return {
       c: rs.fn(),
       d,
     };
   });
   
   it('mocked c', async () => {
     // @ts-expect-error: It has been mocked.
     c('c');
     expect(c).toHaveBeenCalledWith('c');
     expect(d).toBe(4);
   });

2. Issue: async mock factory: In the example below, the async function in the mock factory must be awaited before executing the test case.

   Solution: For the .mock method with a mock factory, insert the line await __webpack_require__.rstest_exec("../src/d"). Additionally, mark all modules with a factory in their .mock methods as async (TLA) so that the previously mentioned await can be used with the module TLA.

   import { d } from '../src/d';
   
   // To test async mocking factory.
   rs.mock('../src/d', async () => {
     await sleep(1000);
     return {
       d: rs.fn(),
     };
   });
   
   it('mocked d', async () => {
     // @ts-expect-error: It has been mocked.
     d('string1');
     expect(d).toHaveBeenCalledWith('string1');
   });

Here's an image to helping understand what init fragments are injected.

Related links

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).