/**
 * @license
 * Copyright Google Inc. 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 {NgZone} from '@angular/core/src/zone/ng_zone';
import {async, fakeAsync, flushMicrotasks} from '@angular/core/testing';
import {AsyncTestCompleter, Log, beforeEach, describe, expect, inject, it, xit} from '@angular/core/testing/src/testing_internal';
import {browserDetection} from '@angular/platform-browser/testing/src/browser_util';
import {scheduleMicroTask} from '../../src/util';

const needsLongerTimers = browserDetection.isSlow || browserDetection.isEdge;
const resultTimer = 1000;
const testTimeout = browserDetection.isEdge ? 1200 : 500;
// Schedules a macrotask (using a timer)
function macroTask(fn: (...args: any[]) => void, timer = 1): void {
  // adds longer timers for passing tests in IE and Edge
  setTimeout(fn, needsLongerTimers ? timer : 1);
}

let _log: Log;
let _errors: any[];
let _traces: any[];
let _zone: NgZone;

const resolvedPromise = Promise.resolve(null);

function logOnError() {
  _zone.onError.subscribe({
    next: (error: any) => {
      _errors.push(error);
      _traces.push(error.stack);
    }
  });
}

function logOnUnstable() {
  _zone.onUnstable.subscribe({next: _log.fn('onUnstable')});
}

function logOnMicrotaskEmpty() {
  _zone.onMicrotaskEmpty.subscribe({next: _log.fn('onMicrotaskEmpty')});
}

function logOnStable() {
  _zone.onStable.subscribe({next: _log.fn('onStable')});
}

function runNgZoneNoLog(fn: () => any) {
  const length = _log.logItems.length;
  try {
    return _zone.run(fn);
  } finally {
    // delete anything which may have gotten logged.
    _log.logItems.length = length;
  }
}

export function main() {
  describe('NgZone', () => {

    function createZone(enableLongStackTrace: boolean) {
      return new NgZone({enableLongStackTrace: enableLongStackTrace});
    }

    beforeEach(() => {
      _log = new Log();
      _errors = [];
      _traces = [];
    });

    describe('long stack trace', () => {
      beforeEach(() => {
        _zone = createZone(true);
        logOnUnstable();
        logOnMicrotaskEmpty();
        logOnStable();
        logOnError();
      });

      commonTests();

      it('should produce long stack traces',
         inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
           macroTask(() => {
             let resolve: (result: any) => void;
             const promise: Promise<any> = new Promise((res) => { resolve = res; });

             _zone.run(() => {
               setTimeout(() => {
                 setTimeout(() => {
                   resolve(null);
                   throw new Error('ccc');
                 }, 0);
               }, 0);
             });

             promise.then((_) => {
               expect(_traces.length).toBe(1);
               expect(_traces[0].length).toBeGreaterThan(1);
               async.done();
             });
           });
         }), testTimeout);

      it('should produce long stack traces (when using microtasks)',
         inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
           macroTask(() => {
             let resolve: (result: any) => void;
             const promise: Promise<any> = new Promise((res) => { resolve = res; });

             _zone.run(() => {
               scheduleMicroTask(() => {
                 scheduleMicroTask(() => {
                   resolve(null);
                   throw new Error('ddd');
                 });
               });
             });

             promise.then((_) => {
               expect(_traces.length).toBe(1);
               expect(_traces[0].length).toBeGreaterThan(1);
               async.done();
             });
           });
         }), testTimeout);
    });

    describe('short stack trace', () => {
      beforeEach(() => {
        _zone = createZone(false);
        logOnUnstable();
        logOnMicrotaskEmpty();
        logOnStable();
        logOnError();
      });

      commonTests();

      it('should disable long stack traces',
         inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
           macroTask(() => {
             let resolve: (result: any) => void;
             const promise: Promise<any> = new Promise((res) => { resolve = res; });

             _zone.run(() => {
               setTimeout(() => {
                 setTimeout(() => {
                   resolve(null);
                   throw new Error('ccc');
                 }, 0);
               }, 0);
             });

             promise.then((_) => {
               expect(_traces.length).toBe(1);
               if (_traces[0] != null) {
                 // some browsers don't have stack traces.
                 expect(_traces[0].indexOf('---')).toEqual(-1);
               }
               async.done();
             });
           });
         }), testTimeout);
    });
  });
}

function commonTests() {
  describe('hasPendingMicrotasks', () => {
    it('should be false', () => { expect(_zone.hasPendingMicrotasks).toBe(false); });

    it('should be true', () => {
      runNgZoneNoLog(() => { scheduleMicroTask(() => {}); });
      expect(_zone.hasPendingMicrotasks).toBe(true);
    });
  });

  describe('hasPendingTimers', () => {
    it('should be false', () => { expect(_zone.hasPendingMacrotasks).toBe(false); });

    it('should be true', () => {
      runNgZoneNoLog(() => { setTimeout(() => {}, 0); });
      expect(_zone.hasPendingMacrotasks).toBe(true);
    });
  });

  describe('hasPendingAsyncTasks', () => {
    it('should be false', () => { expect(_zone.hasPendingMicrotasks).toBe(false); });

    it('should be true when microtask is scheduled', () => {
      runNgZoneNoLog(() => { scheduleMicroTask(() => {}); });
      expect(_zone.hasPendingMicrotasks).toBe(true);
    });

    it('should be true when timer is scheduled', () => {
      runNgZoneNoLog(() => { setTimeout(() => {}, 0); });
      expect(_zone.hasPendingMacrotasks).toBe(true);
    });
  });

  describe('isInInnerZone', () => {
    it('should return whether the code executes in the inner zone', () => {
      expect(NgZone.isInAngularZone()).toEqual(false);
      runNgZoneNoLog(() => { expect(NgZone.isInAngularZone()).toEqual(true); });
    }, testTimeout);
  });

  describe('run', () => {
    it('should return the body return value from run',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         macroTask(() => { expect(_zone.run(() => 6)).toEqual(6); });

         macroTask(() => { async.done(); });
       }), testTimeout);

    it('should call onUnstable and onMicrotaskEmpty',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => macroTask(_log.fn('run')));
         macroTask(() => {
           expect(_log.result()).toEqual('onUnstable; run; onMicrotaskEmpty; onStable');
           async.done();
         });
       }), testTimeout);

    it('should call onStable once at the end of event',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         // The test is set up in a way that causes the zone loop to run onMicrotaskEmpty twice
         // then verified that onStable is only called once at the end

         runNgZoneNoLog(() => macroTask(_log.fn('run')));

         let times = 0;
         _zone.onMicrotaskEmpty.subscribe({
           next: () => {
             times++;
             _log.add(`onMicrotaskEmpty ${times}`);
             if (times < 2) {
               // Scheduling a microtask causes a second digest
               runNgZoneNoLog(() => { scheduleMicroTask(() => {}); });
             }
           }
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   'onUnstable; run; onMicrotaskEmpty; onMicrotaskEmpty 1; ' +
                   'onMicrotaskEmpty; onMicrotaskEmpty 2; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should call standalone onStable',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => macroTask(_log.fn('run')));

         macroTask(() => {
           expect(_log.result()).toEqual('onUnstable; run; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    xit('should run subscriber listeners in the subscription zone (outside)',
        inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
          // Each subscriber fires a microtask outside the Angular zone. The test
          // then verifies that those microtasks do not cause additional digests.

          let turnStart = false;
          _zone.onUnstable.subscribe({
            next: () => {
              if (turnStart) throw 'Should not call this more than once';
              _log.add('onUnstable');
              scheduleMicroTask(() => {});
              turnStart = true;
            }
          });

          let turnDone = false;
          _zone.onMicrotaskEmpty.subscribe({
            next: () => {
              if (turnDone) throw 'Should not call this more than once';
              _log.add('onMicrotaskEmpty');
              scheduleMicroTask(() => {});
              turnDone = true;
            }
          });

          let eventDone = false;
          _zone.onStable.subscribe({
            next: () => {
              if (eventDone) throw 'Should not call this more than once';
              _log.add('onStable');
              scheduleMicroTask(() => {});
              eventDone = true;
            }
          });

          macroTask(() => { _zone.run(_log.fn('run')); });

          macroTask(() => {
            expect(_log.result()).toEqual('onUnstable; run; onMicrotaskEmpty; onStable');
            async.done();
          }, resultTimer);
        }), testTimeout);

    it('should run subscriber listeners in the subscription zone (inside)',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => macroTask(_log.fn('run')));

         // the only practical use-case to run a callback inside the zone is
         // change detection after "onMicrotaskEmpty". That's the only case tested.
         let turnDone = false;
         _zone.onMicrotaskEmpty.subscribe({
           next: () => {
             _log.add('onMyMicrotaskEmpty');
             if (turnDone) return;
             _zone.run(() => { scheduleMicroTask(() => {}); });
             turnDone = true;
           }
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   'onUnstable; run; onMicrotaskEmpty; onMyMicrotaskEmpty; ' +
                   'onMicrotaskEmpty; onMyMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should run async tasks scheduled inside onStable outside Angular zone',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => macroTask(_log.fn('run')));

         _zone.onStable.subscribe({
           next: () => {
             NgZone.assertNotInAngularZone();
             _log.add('onMyTaskDone');
           }
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual('onUnstable; run; onMicrotaskEmpty; onStable; onMyTaskDone');
           async.done();
         });
       }), testTimeout);

    it('should call onUnstable once before a turn and onMicrotaskEmpty once after the turn',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => {
           macroTask(() => {
             _log.add('run start');
             scheduleMicroTask(_log.fn('async'));
             _log.add('run end');
           });
         });

         macroTask(() => {
           // The microtask (async) is executed after the macrotask (run)
           expect(_log.result())
               .toEqual('onUnstable; run start; run end; async; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should not run onUnstable and onMicrotaskEmpty for nested Zone.run',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => {
           macroTask(() => {
             _log.add('start run');
             _zone.run(() => {
               _log.add('nested run');
               scheduleMicroTask(_log.fn('nested run microtask'));
             });
             _log.add('end run');
           });
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   'onUnstable; start run; nested run; end run; nested run microtask; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should not run onUnstable and onMicrotaskEmpty for nested Zone.run invoked from onMicrotaskEmpty',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => macroTask(_log.fn('start run')));

         _zone.onMicrotaskEmpty.subscribe({
           next: () => {
             _log.add('onMicrotaskEmpty:started');
             _zone.run(() => _log.add('nested run'));
             _log.add('onMicrotaskEmpty:finished');
           }
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   'onUnstable; start run; onMicrotaskEmpty; onMicrotaskEmpty:started; nested run; onMicrotaskEmpty:finished; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should call onUnstable and onMicrotaskEmpty before and after each top-level run',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => macroTask(_log.fn('run1')));
         runNgZoneNoLog(() => macroTask(_log.fn('run2')));

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   'onUnstable; run1; onMicrotaskEmpty; onStable; onUnstable; run2; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should call onUnstable and onMicrotaskEmpty before and after each turn',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         let aResolve: (result: string) => void;
         let aPromise: Promise<string>;
         let bResolve: (result: string) => void;
         let bPromise: Promise<string>;

         runNgZoneNoLog(() => {
           macroTask(() => {
             aPromise = new Promise(res => { aResolve = res; });
             bPromise = new Promise(res => { bResolve = res; });

             _log.add('run start');
             aPromise.then(_log.fn('a then'));
             bPromise.then(_log.fn('b then'));
           });
         });

         runNgZoneNoLog(() => {
           macroTask(() => {
             aResolve('a');
             bResolve('b');
           });
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   'onUnstable; run start; onMicrotaskEmpty; onStable; onUnstable; a then; b then; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should run a function outside of the angular zone',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         macroTask(() => { _zone.runOutsideAngular(_log.fn('run')); });

         macroTask(() => {
           expect(_log.result()).toEqual('run');
           async.done();
         });
       }), testTimeout);

    it('should call onUnstable and onMicrotaskEmpty when an inner microtask is scheduled from outside angular',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         let resolve: (result: string | null) => void;
         let promise: Promise<string|null>;

         macroTask(() => {
           NgZone.assertNotInAngularZone();
           promise = new Promise<string|null>(res => { resolve = res; });
         });

         runNgZoneNoLog(() => {
           macroTask(() => {
             NgZone.assertInAngularZone();
             promise.then(_log.fn('executedMicrotask'));
           });
         });

         macroTask(() => {
           NgZone.assertNotInAngularZone();
           _log.add('scheduling a microtask');
           resolve(null);
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   // First VM turn => setup Promise then
                   'onUnstable; onMicrotaskEmpty; onStable; ' +
                   // Second VM turn (outside of angular)
                   'scheduling a microtask; onUnstable; ' +
                   // Third VM Turn => execute the microtask (inside angular)
                   // No onUnstable;  because we don't own the task which started the turn.
                   'executedMicrotask; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should call onUnstable only before executing a microtask scheduled in onMicrotaskEmpty ' +
           'and not onMicrotaskEmpty after executing the task',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => macroTask(_log.fn('run')));

         let ran = false;
         _zone.onMicrotaskEmpty.subscribe({
           next: () => {
             _log.add('onMicrotaskEmpty(begin)');

             if (!ran) {
               _zone.run(() => {
                 scheduleMicroTask(() => {
                   ran = true;
                   _log.add('executedMicrotask');
                 });
               });
             }

             _log.add('onMicrotaskEmpty(end)');
           }
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   // First VM turn => 'run' macrotask
                   'onUnstable; run; onMicrotaskEmpty; onMicrotaskEmpty(begin); onMicrotaskEmpty(end); ' +
                   // Second microtaskDrain Turn => microtask enqueued from onMicrotaskEmpty
                   'executedMicrotask; onMicrotaskEmpty; onMicrotaskEmpty(begin); onMicrotaskEmpty(end); onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should call onUnstable and onMicrotaskEmpty for a scheduleMicroTask in onMicrotaskEmpty triggered by ' +
           'a scheduleMicroTask in run',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => {
           macroTask(() => {
             _log.add('scheduleMicroTask');
             scheduleMicroTask(_log.fn('run(executeMicrotask)'));
           });
         });

         let ran = false;
         _zone.onMicrotaskEmpty.subscribe({
           next: () => {
             _log.add('onMicrotaskEmpty(begin)');
             if (!ran) {
               _log.add('onMicrotaskEmpty(scheduleMicroTask)');
               _zone.run(() => {
                 scheduleMicroTask(() => {
                   ran = true;
                   _log.add('onMicrotaskEmpty(executeMicrotask)');
                 });
               });
             }
             _log.add('onMicrotaskEmpty(end)');
           }
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   // First VM Turn => a macrotask + the microtask it enqueues
                   'onUnstable; scheduleMicroTask; run(executeMicrotask); onMicrotaskEmpty; onMicrotaskEmpty(begin); onMicrotaskEmpty(scheduleMicroTask); onMicrotaskEmpty(end); ' +
                   // Second VM Turn => the microtask enqueued from onMicrotaskEmpty
                   'onMicrotaskEmpty(executeMicrotask); onMicrotaskEmpty; onMicrotaskEmpty(begin); onMicrotaskEmpty(end); onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should execute promises scheduled in onUnstable before promises scheduled in run',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => {
           macroTask(() => {
             _log.add('run start');
             resolvedPromise
                 .then((_) => {
                   _log.add('promise then');
                   resolvedPromise.then(_log.fn('promise foo'));
                   return Promise.resolve(null);
                 })
                 .then(_log.fn('promise bar'));
             _log.add('run end');
           });
         });

         let donePromiseRan = false;
         let startPromiseRan = false;

         _zone.onUnstable.subscribe({
           next: () => {
             _log.add('onUnstable(begin)');
             if (!startPromiseRan) {
               _log.add('onUnstable(schedulePromise)');
               _zone.run(() => { scheduleMicroTask(_log.fn('onUnstable(executePromise)')); });
               startPromiseRan = true;
             }
             _log.add('onUnstable(end)');
           }
         });

         _zone.onMicrotaskEmpty.subscribe({
           next: () => {
             _log.add('onMicrotaskEmpty(begin)');
             if (!donePromiseRan) {
               _log.add('onMicrotaskEmpty(schedulePromise)');
               _zone.run(() => { scheduleMicroTask(_log.fn('onMicrotaskEmpty(executePromise)')); });
               donePromiseRan = true;
             }
             _log.add('onMicrotaskEmpty(end)');
           }
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   // First VM turn: enqueue a microtask in onUnstable
                   'onUnstable; onUnstable(begin); onUnstable(schedulePromise); onUnstable(end); ' +
                   // First VM turn: execute the macrotask which enqueues microtasks
                   'run start; run end; ' +
                   // First VM turn: execute enqueued microtasks
                   'onUnstable(executePromise); promise then; promise foo; promise bar; onMicrotaskEmpty; ' +
                   // First VM turn: onTurnEnd, enqueue a microtask
                   'onMicrotaskEmpty(begin); onMicrotaskEmpty(schedulePromise); onMicrotaskEmpty(end); ' +
                   // Second VM turn: execute the microtask from onTurnEnd
                   'onMicrotaskEmpty(executePromise); onMicrotaskEmpty; onMicrotaskEmpty(begin); onMicrotaskEmpty(end); onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should call onUnstable and onMicrotaskEmpty before and after each turn, respectively',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         let aResolve: (result: string | null) => void;
         let aPromise: Promise<string>;
         let bResolve: (result: string | null) => void;
         let bPromise: Promise<string>;

         runNgZoneNoLog(() => {
           macroTask(() => {
             aPromise = new Promise<string|null>(res => { aResolve = res; });
             bPromise = new Promise<string|null>(res => { bResolve = res; });
             aPromise.then(_log.fn('a then'));
             bPromise.then(_log.fn('b then'));
             _log.add('run start');
           });
         });

         runNgZoneNoLog(() => { macroTask(() => { aResolve(null); }, 10); });

         runNgZoneNoLog(() => { macroTask(() => { bResolve(null); }, 20); });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   // First VM turn
                   'onUnstable; run start; onMicrotaskEmpty; onStable; ' +
                   // Second VM turn
                   'onUnstable; a then; onMicrotaskEmpty; onStable; ' +
                   // Third VM turn
                   'onUnstable; b then; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should call onUnstable and onMicrotaskEmpty before and after (respectively) all turns in a chain',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         runNgZoneNoLog(() => {
           macroTask(() => {
             _log.add('run start');
             scheduleMicroTask(() => {
               _log.add('async1');
               scheduleMicroTask(_log.fn('async2'));
             });
             _log.add('run end');
           });
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   'onUnstable; run start; run end; async1; async2; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);

    it('should call onUnstable and onMicrotaskEmpty for promises created outside of run body',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         let promise: Promise<any>;

         runNgZoneNoLog(() => {
           macroTask(() => {
             _zone.runOutsideAngular(
                 () => { promise = Promise.resolve(4).then((x) => Promise.resolve(x)); });

             promise.then(_log.fn('promise then'));
             _log.add('zone run');
           });
         });

         macroTask(() => {
           expect(_log.result())
               .toEqual(
                   'onUnstable; zone run; onMicrotaskEmpty; onStable; ' +
                   'onUnstable; promise then; onMicrotaskEmpty; onStable');
           async.done();
         }, resultTimer);
       }), testTimeout);
  });

  describe('exceptions', () => {
    it('should call the on error callback when it is invoked via zone.runGuarded',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         macroTask(() => {
           const exception = new Error('sync');

           _zone.runGuarded(() => { throw exception; });

           expect(_errors.length).toBe(1);
           expect(_errors[0]).toBe(exception);
           async.done();
         });
       }), testTimeout);

    it('should not call the on error callback but rethrow when it is invoked via zone.run',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         macroTask(() => {
           const exception = new Error('sync');
           expect(() => _zone.run(() => { throw exception; })).toThrowError('sync');

           expect(_errors.length).toBe(0);
           async.done();
         });
       }), testTimeout);

    it('should call onError for errors from microtasks',
       inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
         const exception = new Error('async');

         macroTask(() => { _zone.run(() => { scheduleMicroTask(() => { throw exception; }); }); });

         macroTask(() => {
           expect(_errors.length).toBe(1);
           expect(_errors[0]).toEqual(exception);
           async.done();
         }, resultTimer);
       }), testTimeout);
  });

  describe('bugs', () => {
    describe('#10503', () => {
      let ngZone: NgZone;

      beforeEach(inject([NgZone], (_ngZone: NgZone) => {
        // Create a zone outside the fakeAsync.
        ngZone = _ngZone;
      }));

      it('should fakeAsync even if the NgZone was created outside.', fakeAsync(() => {
           let result: string = null !;
           // try to escape the current fakeAsync zone by using NgZone which was created outside.
           ngZone.run(() => {
             Promise.resolve('works').then((v) => result = v);
             flushMicrotasks();
           });
           expect(result).toEqual('works');
         }));

      describe('async', () => {
        let asyncResult: string;
        const waitLongerThenTestFrameworkAsyncTimeout = 5;

        beforeEach(() => { asyncResult = null !; });

        it('should async even if the NgZone was created outside.', async(() => {
             // try to escape the current async zone by using NgZone which was created outside.
             ngZone.run(() => {
               setTimeout(() => {
                 Promise.resolve('works').then((v) => asyncResult = v);
               }, waitLongerThenTestFrameworkAsyncTimeout);
             });
           }));

        afterEach(() => { expect(asyncResult).toEqual('works'); });

      });
    });
  });
}
