🐛 BUG: Vitest __mocks__ not working when using @cloudflare/vitest-pool-workers

[saitolume]

Which Cloudflare product(s) does this pertain to?

Workers Vitest Integration

What versions are you using?

2.1.8 [vitest], 0.5.40 [@cloudflare/vitest-pool-workers]

What operating system and version are you using?

macIS Sequoia 15.1.1

Please provide a link to a minimal reproduction

https://github.com/saitolume/workers-sdk-bug-report

Describe the Bug

When using @cloudflare/vitest-pool-workers, the mocks defined in Vitest's __mocks__ directory do not work as expected.

• Expected behavior:
  Modules defined in the __mocks__ directory should automatically be used as mocks.
• Actual behavior:
  When using @cloudflare/vitest-pool-workers, the modules in __mocks__ are not applied. Instead, Vitest's default mocking behavior is used.

Please provide any relevant error logs

pnpm run test:fail                                                                                                                                                                                                                                                                                                                                                        

> @ test:fail /workers-sdk-bug-report
> vitest run --config vitest.fail.config.ts


 RUN  v2.1.8 /workers-sdk-bug-report

[vpw:inf] Starting isolated runtimes for vitest.fail.config.ts...
 ❯ index.test.ts (1)
   × uuid

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Failed Tests 1⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ 

 FAIL  index.test.ts > uuid
AssertionError: expected undefined to be 'expected' // Object.is equality

- Expected: 
"expected"

+ Received: 
undefined

 ❯ index.test.ts:7:16
      5| 
      6| test('uuid', () => {
      7|   expect(v4()).toBe('expected')
       |                ^
      8| })
      9| 

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ [1/1]⎯

 Test Files  1 failed (1)
      Tests  1 failed (1)
   Start at  00:51:16
   Duration  1.04s (transform 10ms, setup 0ms, collect 25ms, tests 6ms, environment 1ms, prepare 107ms)

[vpw:dbg] Shutting down runtimes...
 ELIFECYCLE  Command failed with exit code 1.