Jest单元测试错误:收到的承诺已解决，而不是被拒绝

Question

我试图测试一个异常被抛出，我一直得到这个错误。我觉得我错过了什么。我有这个函数:

async getPreferences(eUserId: string): Promise<UserPreferences> {    
const userPreferences = await this.userPreferencesModel.findOne({
eUserId,
});
if (!userPreferences) {
throw new NotFoundException('no results');
}
return userPreferences;
}

这是我的测试:

it('should throw an error if no userPreferences found', async () => {
// Mock findOne result
jest
.spyOn(model, 'findOne')
.mockResolvedValueOnce(throwError(new NotFoundException()));
const result = service.getPreferences('123123');
// Assertion
await expect(result).rejects.toThrow('no results');
});

这是我在控制台得到的失败错误:

Received promise resolved instead of rejected
Resolved to value: {"_subscribe": [Function init]}
94 |
95 |       // Assertion
> 96 |       await expect(result).rejects.toThrow('no results');
|             ^
97 |     });
98 |   });
99 |
at expect (../node_modules/expect/build/index.js:128:15)
at Object.<anonymous> (user-preferences/user-preferences.service.spec.ts:96:13)

Answer 1

最终是这样的:mockResolvedValue传递null，在service.getPreferencesI中传递一个我知道不存在的值

it('should throw an error if no userPreferences found', async () => {
// Mock findOne result
jest
.spyOn(model, 'findOne')
.mockResolvedValue( null );
// Assertion
expect(service.getPreferences('-1')).rejects.toThrow('no results');
});