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typescript - 如何测试 Nestjs 拦截器?

转载 作者:行者123 更新时间:2023-12-03 22:04:49 26 4
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我找不到关于如何在 NestJS 中测试拦截器的任何解释

这个简单的示例拦截了一个 POST 查询,以将一个属性添加到正文中提供的示例模型中。

@Injectable()
export class SubscriberInterceptor implements NestInterceptor {
async intercept(
context: ExecutionContext,
next: CallHandler,
): Promise<Observable<ExampleModel>> {
let body: ExampleModel = context.switchToHttp().getRequest().body;
body = {
...body,
addedAttribute: 'example',
};
context.switchToHttp().getRequest().body = body;
return next.handle();
}
}

我想测试拦截函数中发生了什么。

迄今为止:

const interceptor = new SubscriberInterceptor();

describe('SubscriberInterceptor', () => {
it('should be defined', () => {
expect(interceptor).toBeDefined();
});

describe('#intercept', () => {
it('should add the addedAttribute to the body', async () => {
expect(await interceptor.intercept(arg1, arg2)).toBe({ ...bodyMock, addedAttribute: 'example' });
});
});
});

我的问题:我应该只模拟 arg1: ExecutionContextarg2: CallHandler ?如果是这样,如何模拟 arg1arg2 ?否则我应该如何进行?

最佳答案

你说得对,你应该 mock arg1arg2 ,然后将它们传递给 intercept方法,这里是解决方案:
SubscriberInterceptor.ts :

interface ExecutionContext {
switchToHttp(): any;
}
interface CallHandler {
handle(): any;
}
interface Observable<T> {}
interface ExampleModel {}

interface NestInterceptor {
intercept(context: ExecutionContext, next: CallHandler): Promise<Observable<ExampleModel>>;
}

export class SubscriberInterceptor implements NestInterceptor {
public async intercept(context: ExecutionContext, next: CallHandler): Promise<Observable<ExampleModel>> {
let body: ExampleModel = context.switchToHttp().getRequest().body;
body = {
...body,
addedAttribute: 'example'
};
context.switchToHttp().getRequest().body = body;
return next.handle();
}
}


单元测试,模拟链接方法 executionContext
import { SubscriberInterceptor } from './';

const interceptor = new SubscriberInterceptor();

const executionContext = {
switchToHttp: jest.fn().mockReturnThis(),
getRequest: jest.fn().mockReturnThis()
};

const callHandler = {
handle: jest.fn()
};

describe('SubscriberInterceptor', () => {
it('should be defined', () => {
expect(interceptor).toBeDefined();
});
describe('#intercept', () => {
it('t1', async () => {
(executionContext.switchToHttp().getRequest as jest.Mock<any, any>).mockReturnValueOnce({
body: { data: 'mocked data' }
});
callHandler.handle.mockResolvedValueOnce('next handle');
const actualValue = await interceptor.intercept(executionContext, callHandler);
expect(actualValue).toBe('next handle');
expect(executionContext.switchToHttp().getRequest().body).toEqual({
data: 'mocked data',
addedAttribute: 'example'
});
expect(callHandler.handle).toBeCalledTimes(1);
});
});
});


单元测试结果:

 PASS  src/mock-function/57730120/index.spec.ts
SubscriberInterceptor
✓ should be defined (10ms)
#intercept
✓ t1 (11ms)

Test Suites: 1 passed, 1 total
Tests: 2 passed, 2 total
Snapshots: 0 total
Time: 1.235s, estimated 3s

关于typescript - 如何测试 Nestjs 拦截器?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57730120/

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