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[英]TestBed.OverrideProvider() doesn't work if TestBed.inject() or TestBed.get() (deprecated) has run before
[英]Angular 13 TestBed doesn't inject interceptor
我有一個帶有自定義 HTTP 客戶端和攔截器的 Angular 13 應用程序,我想對其進行單元測試。
base-url.interceptor.ts
:
import { Inject, Injectable } from '@angular/core';
import { HttpRequest, HttpHandler, HttpEvent, HttpInterceptor } from '@angular/common/http';
import { Observable } from 'rxjs';
export const BASE_API_URL = 'BASE_API_URL';
@Injectable()
export class BaseUrlInterceptor implements HttpInterceptor {
constructor(@Inject(BASE_API_URL) private baseUrl: string) {}
intercept(request: HttpRequest<unknown>, next: HttpHandler): Observable<HttpEvent<unknown>> {
const apiRequest = request.clone({ url: `${this.baseUrl}${request.url}` });
return next.handle(apiRequest);
}
}
base-url.interceptor.spec.ts
:
import { TestBed } from '@angular/core/testing';
import { ApiHttpService, API_HTTP_INTERCEPTORS } from '../api-http.service';
import { BaseUrlInterceptor, BASE_API_URL } from './base-url.interceptor';
describe('BaseUrlInterceptor', () => {
let interceptor: BaseUrlInterceptor;
beforeEach(() => {
TestBed.configureTestingModule({
imports: [],
providers: [
ApiHttpService,
{ provide: BASE_API_URL, value: 'http://example.com' },
{ provide: API_HTTP_INTERCEPTORS, useClass: BaseUrlInterceptor, multi: true }
]
});
interceptor = TestBed.inject(BaseUrlInterceptor);
});
it('should be created', () => {
expect(interceptor).toBeTruthy();
});
});
不幸的是TestBed.inject(BaseUrlInterceptor)
未能注入攔截器的實例。 interceptor
器總是undefined
。 如果我通過手動創建實例來解決這個問題new BaseUrlInterceptor('http://example.com');
它有效,但其他攔截器有進一步的依賴關系,我想在這里使用 Angulars 依賴注入。
我如何配置 TestBed,以便它可以成功創建BaseUrlInterceptor
的實例?
我創建了一個重現問題的最小 CodeSandbox: https://codesandbox.io/s/snowy-dust-t964no?file=/src/app/base-url.interceptor.spec.ts
此外,當我運行錯誤測試時,我收到此錯誤消息:
Chrome Headless 98.0.4758.102 (Linux x86_64) BaseUrlInterceptor should be created FAILED
Error: NG0204: unreachable
error properties: Object({ code: 204 })
Error: NG0204: unreachable
at injectableDefOrInjectorDefFactory (node_modules/@angular/core/fesm2015/core.mjs:11494:1)
at providerToFactory (node_modules/@angular/core/fesm2015/core.mjs:11556:1)
at providerToRecord (node_modules/@angular/core/fesm2015/core.mjs:11521:1)
at R3Injector.processProvider (node_modules/@angular/core/fesm2015/core.mjs:11424:1)
at node_modules/@angular/core/fesm2015/core.mjs:11410:1
at node_modules/@angular/core/fesm2015/core.mjs:4162:1
at Array.forEach (<anonymous>)
at deepForEach (node_modules/@angular/core/fesm2015/core.mjs:4162:1)
at R3Injector.processInjectorType (node_modules/@angular/core/fesm2015/core.mjs:11410:1)
at node_modules/@angular/core/fesm2015/core.mjs:11213:1
Error: Expected undefined to be truthy.
at <Jasmine>
at UserContext.<anonymous> (projects/frontend/src/app/core/http/interceptors/base-url.interceptor.spec.ts:21:25)
at ZoneDelegate.invoke (node_modules/zone.js/fesm2015/zone.js:372:1)
at ProxyZoneSpec.onInvoke (node_modules/zone.js/fesm2015/zone-testing.js:287:1)
Chrome Headless 98.0.4758.102 (Linux x86_64): Executed 1 of 1 (1 FAILED) (0.072 secs / 0.056 secs)
TOTAL: 1 FAILED, 0 SUCCESS
您收到Error: NG0204: unreachable
是因為當您為BASE_API_URL
定義提供程序時,您使用的是屬性value
,而它應該是useValue
。
{ provide: BASE_API_URL, useValue: 'http://example.com' },
無論如何,即使你修復了它,你也會得到一個NullInjectorError
,因為你沒有定義一個使用BaseUrlInterceptor
class 作為 InjectionToken 的提供者。 您正在使用 class 作為API_HTTP_INTERCEPTORS
令牌的提供者之一。
在對攔截器進行單元測試的上下文中,您應該擺脫 ApiHttpService,而只關注攔截器 class。
你有兩個選擇:
手動實例化 class
beforeEach(() => {
interceptor = new BaseUrlInterceptor('http://example.com');
});
或者在 Testbed 中使用攔截器 class 作為提供者
beforeEach(() => {
TestBed.configureTestingModule({
imports: [],
providers: [
{ provide: BASE_API_URL, useValue: 'http://example.com' },
BaseUrlInterceptor,
],
});
interceptor = TestBed.inject(BaseUrlInterceptor);
});
干杯
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