async-testing.ts

/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
import '../zone-spec/async-test';

Zone.__load_patch('asynctest', (global: any, Zone: ZoneType, api: _ZonePrivate) => {
  /**
   * Wraps a test function in an asynchronous test zone. The test will automatically
   * complete when all asynchronous calls within this zone are done.
   */
  (Zone as any)[api.symbol('asyncTest')] = function asyncTest(fn: Function): (done: any) => any {
    // If we're running using the Jasmine test framework, adapt to call the 'done'
    // function when asynchronous activity is finished.
    if (global.jasmine) {
      // Not using an arrow function to preserve context passed from call site
      return function(this: unknown, done: any) {
        if (!done) {
          // if we run beforeEach in @angular/core/testing/testing_internal then we get no done
          // fake it here and assume sync.
          done = function() {};
          done.fail = function(e: any) {
            throw e;
          };
        }
        runInTestZone(fn, this, done, (err: any) => {
          if (typeof err === 'string') {
            return done.fail(new Error(err));
          } else {
            done.fail(err);
          }
        });
      };
    }
    // Otherwise, return a promise which will resolve when asynchronous activity
    // is finished. This will be correctly consumed by the Mocha framework with
    // it('...', async(myFn)); or can be used in a custom framework.
    // Not using an arrow function to preserve context passed from call site
    return function(this: unknown) {
      return new Promise<void>((finishCallback, failCallback) => {
        runInTestZone(fn, this, finishCallback, failCallback);
      });
    };
  };

  function runInTestZone(
      fn: Function, context: any, finishCallback: Function, failCallback: Function) {
    const currentZone = Zone.current;
    const AsyncTestZoneSpec = (Zone as any)['AsyncTestZoneSpec'];
    if (AsyncTestZoneSpec === undefined) {
      throw new Error(
          'AsyncTestZoneSpec is needed for the async() test helper but could not be found. ' +
          'Please make sure that your environment includes zone.js/dist/async-test.js');
    }
    const ProxyZoneSpec = (Zone as any)['ProxyZoneSpec'] as {
      get(): {setDelegate(spec: ZoneSpec): void; getDelegate(): ZoneSpec;};
      assertPresent: () => void;
    };
    if (ProxyZoneSpec === undefined) {
      throw new Error(
          'ProxyZoneSpec is needed for the async() test helper but could not be found. ' +
          'Please make sure that your environment includes zone.js/dist/proxy.js');
    }
    const proxyZoneSpec = ProxyZoneSpec.get();
    ProxyZoneSpec.assertPresent();
    // We need to create the AsyncTestZoneSpec outside the ProxyZone.
    // If we do it in ProxyZone then we will get to infinite recursion.
    const proxyZone = Zone.current.getZoneWith('ProxyZoneSpec');
    const previousDelegate = proxyZoneSpec.getDelegate();
    proxyZone!.parent!.run(() => {
      const testZoneSpec: ZoneSpec = new AsyncTestZoneSpec(
          () => {
            // Need to restore the original zone.
            if (proxyZoneSpec.getDelegate() == testZoneSpec) {
              // Only reset the zone spec if it's
              // sill this one. Otherwise, assume
              // it's OK.
              proxyZoneSpec.setDelegate(previousDelegate);
            }
            (testZoneSpec as any).unPatchPromiseForTest();
            currentZone.run(() => {
              finishCallback();
            });
          },
          (error: any) => {
            // Need to restore the original zone.
            if (proxyZoneSpec.getDelegate() == testZoneSpec) {
              // Only reset the zone spec if it's sill this one. Otherwise, assume it's OK.
              proxyZoneSpec.setDelegate(previousDelegate);
            }
            (testZoneSpec as any).unPatchPromiseForTest();
            currentZone.run(() => {
              failCallback(error);
            });
          },
          'test');
      proxyZoneSpec.setDelegate(testZoneSpec);
      (testZoneSpec as any).patchPromiseForTest();
    });
    return Zone.current.runGuarded(fn, context);
  }
});