feat(vitest): add return type and promisable mockFactory

packages/vitest/src/types/mocker.ts

@@ -1,6 +1,8 @@
+type Promisable<T> = T | Promise<T>
+
 export type MockFactoryWithHelper<M = unknown> = (
-  importOriginal: <T extends M>() => Promise<T>
-) => any
+  importOriginal: <T extends M = M>() => Promise<T>
+) => Promisable<M | null>
 export type MockFactory = () => any
 
 export type MockMap = Map<string, Record<string, string | null | MockFactory>>

test/config/test/workers-option.test.ts

@@ -4,6 +4,7 @@ import { getWorkersCountByPercentage } from 'vitest/src/utils/workers.js'
 import * as testUtils from '../../test-utils'
 
 vi.mock(import('node:os'), async importOriginal => ({
+  ...(await importOriginal()),
   default: {
     ...(await importOriginal()).default,
     availableParallelism: () => 10,