When defining a mock that will return a rejected promise using .thenReject(new Error()) and this mock will not be called, the test succeeds but throws the error defined in the thenReject function.
Expected behavior
The test will succeed without throwing the error.
Example test that reproduces the problem
it('should fail minimal', () => {
const spy = vi.fn()
subject.when(spy).calledWith('/api/foo').thenReject(new Error('uh uhh'))
// intentionally do not call the spy
expect(true).toBe(true)
})
The output of the failing test
✓ test/vitest-when.test.ts (24)
✓ example/meaning-of-life.test.ts (1)
⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Unhandled Errors ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
Vitest caught 1 unhandled error during the test run.
This might cause false positive tests. Resolve unhandled errors to make sure your tests are not affected.
⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Unhandled Rejection ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
Error: uh uhh
❯ test/vitest-when.test.ts:160:57
158| it('should fail minimal', () => {
159| const spy = vi.fn()
160| subject.when(spy).calledWith('/api/foo').thenReject(new Error('uh uhh'))
| ^
161| // intentionally do not call the spy
162| expect(true).toBe(true)
❯ node_modules/.pnpm/@vitest+runner@1.0.1/node_modules/@vitest/runner/dist/index.js:127:14
❯ node_modules/.pnpm/@vitest+runner@1.0.1/node_modules/@vitest/runner/dist/index.js:59:26
❯ runTest node_modules/.pnpm/@vitest+runner@1.0.1/node_modules/@vitest/runner/dist/index.js:672:17
❯ runSuite node_modules/.pnpm/@vitest+runner@1.0.1/node_modules/@vitest/runner/dist/index.js:789:15
❯ runSuite node_modules/.pnpm/@vitest+runner@1.0.1/node_modules/@vitest/runner/dist/index.js:789:15
❯ runFiles node_modules/.pnpm/@vitest+runner@1.0.1/node_modules/@vitest/runner/dist/index.js:838:5
❯ startTests node_modules/.pnpm/@vitest+runner@1.0.1/node_modules/@vitest/runner/dist/index.js:847:3
❯ node_modules/.pnpm/vitest@1.0.1/node_modules/vitest/dist/entry.js:112:7
❯ withEnv node_modules/.pnpm/vitest@1.0.1/node_modules/vitest/dist/entry.js:79:5
This error originated in "test/vitest-when.test.ts" test file. It doesn't mean the error was thrown inside the file itself, but while it was running.
⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯
Test Files 2 passed (2)
Tests 25 passed (25)
Errors 1 error
Start at 08:25:26
Duration 237ms (transform 64ms, setup 0ms, collect 104ms, tests 11ms, environment 0ms, prepare 113ms)
Side note
Using thenDo will not reproduce the above problem:
it("should work", () => {
const spy = vi.fn()
subject.when(spy).calledWith('/api/foo').thenDo(() => new Error('uh uhh'))
// intentionally do not call the spy
expect(true).toBe(true)
})
Bug description
When defining a mock that will return a rejected promise using
.thenReject(new Error())
and this mock will not be called, the test succeeds but throws the error defined in thethenReject
function.Expected behavior
The test will succeed without throwing the error.
Example test that reproduces the problem
The output of the failing test
Side note
Using
thenDo
will not reproduce the above problem: