api.interceptor.spec.ts

import { HttpHandler, HttpRequest } from '@angular/common/http';
import { inject, TestBed } from '@angular/core/testing';
import { AppError } from '@devatscience/ngx-errors';
import { of } from 'rxjs';
import { catchError } from 'rxjs/operators';

import { ApiInterceptor } from './api.interceptor';
import { Configuration } from '../configuration';
import { MarbleFormatter, MarbleTestScheduler } from '../testing/marbles';

describe('ApiInterceptor', () => {
  const API_BASE_URL = 'http://test.com';
  const API_PATH = '/foo/bar';
  const API_URL = `${API_BASE_URL}${API_PATH}`;
  const OTHER_URL = 'http://example.com/foo/bar';
  const RESPONSE = 'OK';

  const VALUES = {
    n: null as null,
    r: RESPONSE,
  };

  let scheduler: MarbleTestScheduler<any>;
  let next: jasmine.SpyObj<HttpHandler>;
  let conf: Configuration;

  beforeEach(() => {
    scheduler = new MarbleTestScheduler(new MarbleFormatter(VALUES));

    next = jasmine.createSpyObj('HttpHandler', ['handle']);

    conf = new Configuration();
    conf.apiBaseURL = API_BASE_URL;

    TestBed.configureTestingModule({
      providers: [ApiInterceptor, { provide: Configuration, useValue: conf }],
    });
  });

  it('should be created', inject(
    [ApiInterceptor],
    (service: ApiInterceptor) => {
      expect(service).toBeTruthy();
    }
  ));

  function testUrl(input: string, expected: string): void {
    const NEXT_M = /***/ '--r';
    const INTER_M = /**/ '--r';

    const req = new HttpRequest('GET', input);

    scheduler.run(({ expectObservable, cold }) => {
      next.handle.and.callFake((r: HttpRequest<any>) => {
        expect(r.url).toEqual(expected);
        return cold(NEXT_M);
      });

      inject([ApiInterceptor], (service: ApiInterceptor) =>
        expectObservable(service.intercept(req, next)).toBe(INTER_M)
      )();
    });
  }

  it('should prepend the base URL to hostless URLs', () => testUrl(API_PATH, API_URL));

  it('should not prepend the base URL to full API URLs', () => testUrl(API_URL, API_URL));

  it('should not change other URLs', () => testUrl(OTHER_URL, OTHER_URL));