angular-docs-cn/modules/angular2/test/change_detection/change_detector_spec.ts

///<reference path="../../src/change_detection/pipes/pipe.ts"/>
import {
  ddescribe,
  describe,
  it,
  iit,
  xit,
  expect,
  beforeEach,
  afterEach,
  IS_DARTIUM
} from 'angular2/test_lib';

import {
  CONST_EXPR,
  isPresent,
  isBlank,
  isJsObject,
  BaseException,
  FunctionWrapper
} from 'angular2/src/facade/lang';
import {List, ListWrapper, MapWrapper, StringMapWrapper} from 'angular2/src/facade/collection';

import {
  ChangeDispatcher,
  DehydratedException,
  DynamicChangeDetector,
  ChangeDetectionError,
  BindingRecord,
  DirectiveRecord,
  DirectiveIndex,
  PipeRegistry,
  Pipe,
  CHECK_ALWAYS,
  CHECK_ONCE,
  CHECKED,
  DETACHED,
  ON_PUSH,
  DEFAULT,
  WrappedValue,
  DynamicProtoChangeDetector,
  ChangeDetectorDefinition,
  Lexer,
  Parser,
  Locals,
  ProtoChangeDetector
} from 'angular2/change_detection';
import {JitProtoChangeDetector} from 'angular2/src/change_detection/jit_proto_change_detector';

import {getDefinition} from './change_detector_config';
import {getFactoryById} from './generated/change_detector_classes';

const _DEFAULT_CONTEXT = CONST_EXPR(new Object());

/**
 * Tests in this spec run against three different implementations of `AbstractChangeDetector`,
 * `dynamic` (which use reflection to inspect objects), `JIT` (which are generated only for
 * Javascript at runtime using `eval`) and `Pregen` (which are generated only for Dart prior
 * to app deploy to avoid the need for reflection).
 *
 * Pre-generated classes require knowledge of the shape of the change detector at the time of Dart
 * transformation, so in these tests we abstract a `ChangeDetectorDefinition` out into the
 * change_detector_config library and define a build step which pre-generates the necessary change
 * detectors to execute these tests. Once that built step has run, those generated change detectors
 * can be found in the generated/change_detector_classes library.
 */
export function main() {
  ListWrapper.forEach(['dynamic', 'JIT', 'Pregen'], (cdType) => {
    if (cdType == "JIT" && IS_DARTIUM) return;
    if (cdType == "Pregen" && !IS_DARTIUM) return;

    describe(`${cdType} Change Detector`, () => {

      function _getProtoChangeDetector(def: ChangeDetectorDefinition) {
        switch (cdType) {
          case 'dynamic':
            return new DynamicProtoChangeDetector(def);
          case 'JIT':
            return new JitProtoChangeDetector(def);
          case 'Pregen':
            return getFactoryById(def.id)(def);
          default:
            return null;
        }
      }

      function _createWithoutHydrate(expression: string) {
        var dispatcher = new TestDispatcher();
        var cd = _getProtoChangeDetector(getDefinition(expression).cdDef).instantiate(dispatcher);
        return new _ChangeDetectorAndDispatcher(cd, dispatcher);
      }


      function _createChangeDetector(expression: string, context = _DEFAULT_CONTEXT,
                                     registry = null) {
        var dispatcher = new TestDispatcher();
        var testDef = getDefinition(expression);
        var protoCd = _getProtoChangeDetector(testDef.cdDef);
        var cd = protoCd.instantiate(dispatcher);
        cd.hydrate(context, testDef.locals, null, registry);
        return new _ChangeDetectorAndDispatcher(cd, dispatcher);
      }

      function _bindSimpleValue(expression: string, context = _DEFAULT_CONTEXT) {
        var val = _createChangeDetector(expression, context);
        val.changeDetector.detectChanges();
        return val.dispatcher.log;
      }

      it('should support literals',
         () => { expect(_bindSimpleValue('10')).toEqual(['propName=10']); });

      it('should strip quotes from literals',
         () => { expect(_bindSimpleValue('"str"')).toEqual(['propName=str']); });

      it('should support newlines in literals',
         () => { expect(_bindSimpleValue('"a\n\nb"')).toEqual(['propName=a\n\nb']); });

      it('should support + operations',
         () => { expect(_bindSimpleValue('10 + 2')).toEqual(['propName=12']); });

      it('should support - operations',
         () => { expect(_bindSimpleValue('10 - 2')).toEqual(['propName=8']); });

      it('should support * operations',
         () => { expect(_bindSimpleValue('10 * 2')).toEqual(['propName=20']); });

      it('should support / operations', () => {
        expect(_bindSimpleValue('10 / 2')).toEqual([`propName=${5.0}`]);
      });  // dart exp=5.0, js exp=5

      it('should support % operations',
         () => { expect(_bindSimpleValue('11 % 2')).toEqual(['propName=1']); });

      it('should support == operations on identical',
         () => { expect(_bindSimpleValue('1 == 1')).toEqual(['propName=true']); });

      it('should support != operations',
         () => { expect(_bindSimpleValue('1 != 1')).toEqual(['propName=false']); });

      it('should support == operations on coerceible', () => {
        var expectedValue = IS_DARTIUM ? 'false' : 'true';
        expect(_bindSimpleValue('1 == true')).toEqual([`propName=${expectedValue}`]);
      });

      it('should support === operations on identical',
         () => { expect(_bindSimpleValue('1 === 1')).toEqual(['propName=true']); });

      it('should support !== operations',
         () => { expect(_bindSimpleValue('1 !== 1')).toEqual(['propName=false']); });

      it('should support === operations on coerceible',
         () => { expect(_bindSimpleValue('1 === true')).toEqual(['propName=false']); });

      it('should support true < operations',
         () => { expect(_bindSimpleValue('1 < 2')).toEqual(['propName=true']); });

      it('should support false < operations',
         () => { expect(_bindSimpleValue('2 < 1')).toEqual(['propName=false']); });

      it('should support false > operations',
         () => { expect(_bindSimpleValue('1 > 2')).toEqual(['propName=false']); });

      it('should support true > operations',
         () => { expect(_bindSimpleValue('2 > 1')).toEqual(['propName=true']); });

      it('should support true <= operations',
         () => { expect(_bindSimpleValue('1 <= 2')).toEqual(['propName=true']); });

      it('should support equal <= operations',
         () => { expect(_bindSimpleValue('2 <= 2')).toEqual(['propName=true']); });

      it('should support false <= operations',
         () => { expect(_bindSimpleValue('2 <= 1')).toEqual(['propName=false']); });

      it('should support true >= operations',
         () => { expect(_bindSimpleValue('2 >= 1')).toEqual(['propName=true']); });

      it('should support equal >= operations',
         () => { expect(_bindSimpleValue('2 >= 2')).toEqual(['propName=true']); });

      it('should support false >= operations',
         () => { expect(_bindSimpleValue('1 >= 2')).toEqual(['propName=false']); });

      it('should support true && operations',
         () => { expect(_bindSimpleValue('true && true')).toEqual(['propName=true']); });

      it('should support false && operations',
         () => { expect(_bindSimpleValue('true && false')).toEqual(['propName=false']); });

      it('should support true || operations',
         () => { expect(_bindSimpleValue('true || false')).toEqual(['propName=true']); });

      it('should support false || operations',
         () => { expect(_bindSimpleValue('false || false')).toEqual(['propName=false']); });

      it('should support negate',
         () => { expect(_bindSimpleValue('!true')).toEqual(['propName=false']); });

      it('should support double negate',
         () => { expect(_bindSimpleValue('!!true')).toEqual(['propName=true']); });

      it('should support true conditionals',
         () => { expect(_bindSimpleValue('1 < 2 ? 1 : 2')).toEqual(['propName=1']); });

      it('should support false conditionals',
         () => { expect(_bindSimpleValue('1 > 2 ? 1 : 2')).toEqual(['propName=2']); });

      it('should support keyed access to a list item',
         () => { expect(_bindSimpleValue('["foo", "bar"][0]')).toEqual(['propName=foo']); });

      it('should support keyed access to a map item',
         () => { expect(_bindSimpleValue('{"foo": "bar"}["foo"]')).toEqual(['propName=bar']); });

      it('should report all changes on the first run including uninitialized values', () => {
        expect(_bindSimpleValue('value', new Uninitialized())).toEqual(['propName=null']);
      });

      it('should report all changes on the first run including null values', () => {
        var td = new TestData(null);
        expect(_bindSimpleValue('a', td)).toEqual(['propName=null']);
      });

      it('should support simple chained property access', () => {
        var address = new Address('Grenoble');
        var person = new Person('Victor', address);

        expect(_bindSimpleValue('address.city', person)).toEqual(['propName=Grenoble']);
      });

      it('should support the safe navigation operator', () => {
        var person = new Person('Victor', null);

        expect(_bindSimpleValue('address?.city', person)).toEqual(['propName=null']);
        expect(_bindSimpleValue('address?.toString()', person)).toEqual(['propName=null']);

        person.address = new Address('MTV');

        expect(_bindSimpleValue('address?.city', person)).toEqual(['propName=MTV']);
        expect(_bindSimpleValue('address?.toString()', person)).toEqual(['propName=MTV']);
      });

      it('should support method calls', () => {
        var person = new Person('Victor');
        expect(_bindSimpleValue('sayHi("Jim")', person)).toEqual(['propName=Hi, Jim']);
      });

      it('should support function calls', () => {
        var td = new TestData(() => (a) => a);
        expect(_bindSimpleValue('a()(99)', td)).toEqual(['propName=99']);
      });

      it('should support chained method calls', () => {
        var person = new Person('Victor');
        var td = new TestData(person);
        expect(_bindSimpleValue('a.sayHi("Jim")', td)).toEqual(['propName=Hi, Jim']);
      });

      it('should do simple watching', () => {
        var person = new Person('misko');
        var val = _createChangeDetector('name', person);

        val.changeDetector.detectChanges();
        expect(val.dispatcher.log).toEqual(['propName=misko']);
        val.dispatcher.clear();

        val.changeDetector.detectChanges();
        expect(val.dispatcher.log).toEqual([]);
        val.dispatcher.clear();

        person.name = 'Misko';
        val.changeDetector.detectChanges();
        expect(val.dispatcher.log).toEqual(['propName=Misko']);
      });

      it('should support literal array', () => {
        var val = _createChangeDetector('[1, 2]');
        val.changeDetector.detectChanges();
        expect(val.dispatcher.loggedValues).toEqual([[1, 2]]);

        val = _createChangeDetector('[1, a]', new TestData(2));
        val.changeDetector.detectChanges();
        expect(val.dispatcher.loggedValues).toEqual([[1, 2]]);
      });

      it('should support literal maps', () => {
        var val = _createChangeDetector('{z: 1}');
        val.changeDetector.detectChanges();
        expect(val.dispatcher.loggedValues[0]['z']).toEqual(1);

        val = _createChangeDetector('{z: a}', new TestData(1));
        val.changeDetector.detectChanges();
        expect(val.dispatcher.loggedValues[0]['z']).toEqual(1);
      });

      it('should support interpolation', () => {
        var val = _createChangeDetector('interpolation', new TestData('value'));
        val.changeDetector.hydrate(new TestData('value'), null, null, null);

        val.changeDetector.detectChanges();

        expect(val.dispatcher.log).toEqual(['propName=BvalueA']);
      });

      describe('pure functions', () => {
        it('should preserve memoized result', () => {
          var person = new Person('bob');
          var val = _createChangeDetector('passThrough([12])', person);
          val.changeDetector.detectChanges();
          val.changeDetector.detectChanges();
          expect(val.dispatcher.loggedValues).toEqual([[12]]);
        });
      });

      describe('change notification', () => {
        describe('simple checks', () => {
          it('should pass a change record to the dispatcher', () => {
            var person = new Person('bob');
            var val = _createChangeDetector('name', person);
            val.changeDetector.detectChanges();
            expect(val.dispatcher.loggedValues).toEqual(['bob']);
          });
        });

        describe('pipes', () => {
          it('should pass a change record to the dispatcher', () => {
            var registry = new FakePipeRegistry('pipe', () => new CountingPipe());
            var person = new Person('bob');
            var val = _createChangeDetector('name | pipe', person, registry);
            val.changeDetector.detectChanges();
            expect(val.dispatcher.loggedValues).toEqual(['bob state:0']);
          });

          it('should support arguments in pipes', () => {
            var registry = new FakePipeRegistry('pipe', () => new MultiArgPipe());
            var address = new Address('two');
            var person = new Person('value', address);
            var val = _createChangeDetector("name | pipe:'one':address.city", person, registry);
            val.changeDetector.detectChanges();
            expect(val.dispatcher.loggedValues).toEqual(['value one two default']);
          });
        });

        it('should notify the dispatcher on all changes done', () => {
          var val = _createChangeDetector('name', new Person('bob'));
          val.changeDetector.detectChanges();
          expect(val.dispatcher.onAllChangesDoneCalled).toEqual(true);
        });

        describe('updating directives', () => {
          var directive1;
          var directive2;

          beforeEach(() => {
            directive1 = new TestDirective();
            directive2 = new TestDirective();
          });

          it('should happen directly, without invoking the dispatcher', () => {
            var val = _createWithoutHydrate('directNoDispatcher');
            val.changeDetector.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive1], []),
                                       null);
            val.changeDetector.detectChanges();
            expect(val.dispatcher.loggedValues).toEqual([]);
            expect(directive1.a).toEqual(42);
          });

          describe('onChange', () => {
            it('should notify the directive when a group of records changes', () => {
              var cd = _createWithoutHydrate('groupChanges').changeDetector;
              cd.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive1, directive2], []),
                         null);
              cd.detectChanges();
              expect(directive1.changes).toEqual({'a': 1, 'b': 2});
              expect(directive2.changes).toEqual({'a': 3});
            });
          });

          describe('onCheck', () => {
            it('should notify the directive when it is checked', () => {
              var cd = _createWithoutHydrate('directiveOnCheck').changeDetector;

              cd.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive1], []), null);
              cd.detectChanges();

              expect(directive1.onCheckCalled).toBe(true);
              directive1.onCheckCalled = false;

              cd.detectChanges();
              expect(directive1.onCheckCalled).toBe(true);
            });

            it('should not call onCheck in detectNoChanges', () => {
              var cd = _createWithoutHydrate('directiveOnCheck').changeDetector;

              cd.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive1], []), null);

              cd.checkNoChanges();

              expect(directive1.onCheckCalled).toBe(false);
            });
          });

          describe('onInit', () => {
            it('should notify the directive after it has been checked the first time', () => {
              var cd = _createWithoutHydrate('directiveOnInit').changeDetector;

              cd.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive1], []), null);

              cd.detectChanges();

              expect(directive1.onInitCalled).toBe(true);

              directive1.onInitCalled = false;

              cd.detectChanges();

              expect(directive1.onInitCalled).toBe(false);
            });

            it('should not call onInit in detectNoChanges', () => {
              var cd = _createWithoutHydrate('directiveOnInit').changeDetector;

              cd.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive1], []), null);

              cd.checkNoChanges();

              expect(directive1.onInitCalled).toBe(false);
            });
          });

          describe('onAllChangesDone', () => {
            it('should be called after processing all the children', () => {
              var cd = _createWithoutHydrate('emptyWithDirectiveRecords').changeDetector;
              cd.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive1, directive2], []),
                         null);

              cd.detectChanges();

              expect(directive1.onChangesDoneCalled).toBe(true);
              expect(directive2.onChangesDoneCalled).toBe(true);

              // reset directives
              directive1.onChangesDoneCalled = false;
              directive2.onChangesDoneCalled = false;

              // Verify that checking should not call them.
              cd.checkNoChanges();

              expect(directive1.onChangesDoneCalled).toBe(false);
              expect(directive2.onChangesDoneCalled).toBe(false);

              // re-verify that changes are still detected
              cd.detectChanges();

              expect(directive1.onChangesDoneCalled).toBe(true);
              expect(directive2.onChangesDoneCalled).toBe(true);
            });


            it('should not be called when onAllChangesDone is false', () => {
              var cd = _createWithoutHydrate('noCallbacks').changeDetector;

              cd.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive1], []), null);

              cd.detectChanges();

              expect(directive1.onChangesDoneCalled).toEqual(false);
            });

            it('should be called in reverse order so the child is always notified before the parent',
               () => {
                 var cd = _createWithoutHydrate('emptyWithDirectiveRecords').changeDetector;

                 var onChangesDoneCalls = [];
                 var td1;
                 td1 = new TestDirective(() => onChangesDoneCalls.push(td1));
                 var td2;
                 td2 = new TestDirective(() => onChangesDoneCalls.push(td2));
                 cd.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([td1, td2], []), null);

                 cd.detectChanges();

                 expect(onChangesDoneCalls).toEqual([td2, td1]);
               });

            it('should be called before processing shadow dom children', () => {
              var parent = _createWithoutHydrate('directNoDispatcher').changeDetector;
              var child = _createWithoutHydrate('directNoDispatcher').changeDetector;
              parent.addShadowDomChild(child);

              var orderOfOperations = [];

              var directiveInShadowDom = null;
              directiveInShadowDom =
                  new TestDirective(() => { orderOfOperations.push(directiveInShadowDom); });
              var parentDirective = null;
              parentDirective =
                  new TestDirective(() => { orderOfOperations.push(parentDirective); });

              parent.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([parentDirective], []),
                             null);
              child.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directiveInShadowDom], []),
                            null);

              parent.detectChanges();
              expect(orderOfOperations).toEqual([parentDirective, directiveInShadowDom]);
            });
          });
        });
      });

      describe('reading directives', () => {
        it('should read directive properties', () => {
          var directive = new TestDirective();
          directive.a = 'aaa';

          var val = _createWithoutHydrate('readingDirectives');
          val.changeDetector.hydrate(_DEFAULT_CONTEXT, null, new FakeDirectives([directive], []),
                                     null);

          val.changeDetector.detectChanges();

          expect(val.dispatcher.loggedValues).toEqual(['aaa']);
        });
      });

      describe('enforce no new changes', () => {
        it('should throw when a record gets changed after it has been checked', () => {
          var val = _createChangeDetector('a', new TestData('value'));
          expect(() => { val.changeDetector.checkNoChanges(); })
              .toThrowError(new RegExp(
                  'Expression [\'"]a in location[\'"] has changed after it was checked'));
        });

        it('should not break the next run', () => {
          var val = _createChangeDetector('a', new TestData('value'));
          expect(() => val.changeDetector.checkNoChanges())
              .toThrowError(new RegExp(
                  'Expression [\'"]a in location[\'"] has changed after it was checked.'));

          val.changeDetector.detectChanges();
          expect(val.dispatcher.loggedValues).toEqual(['value']);
        });
      });

      describe('error handling', () => {
        it('should wrap exceptions into ChangeDetectionError', () => {
          var val = _createChangeDetector('invalidFn(1)');
          try {
            val.changeDetector.detectChanges();
            throw new BaseException('fail');
          } catch (e) {
            expect(e).toBeAnInstanceOf(ChangeDetectionError);
            expect(e.location).toEqual('invalidFn(1) in location');
          }
        });
      });

      describe('Locals', () => {
        it('should read a value from locals',
           () => { expect(_bindSimpleValue('valueFromLocals')).toEqual(['propName=value']); });

        it('should invoke a function from local',
           () => { expect(_bindSimpleValue('functionFromLocals')).toEqual(['propName=value']); });

        it('should handle nested locals',
           () => { expect(_bindSimpleValue('nestedLocals')).toEqual(['propName=value']); });

        it('should fall back to a regular field read when the locals map' +
               'does not have the requested field',
           () => {
             expect(_bindSimpleValue('fallbackLocals', new Person('Jim')))
                 .toEqual(['propName=Jim']);
           });

        it('should correctly handle nested properties', () => {
          var address = new Address('Grenoble');
          var person = new Person('Victor', address);

          expect(_bindSimpleValue('contextNestedPropertyWithLocals', person))
              .toEqual(['propName=Grenoble']);
          expect(_bindSimpleValue('localPropertyWithSimilarContext', person))
              .toEqual(['propName=MTV']);
        });
      });

      describe('handle children', () => {
        var parent, child;

        beforeEach(() => {
          parent = _createChangeDetector('10').changeDetector;
          child = _createChangeDetector('"str"').changeDetector;
        });

        it('should add light dom children', () => {
          parent.addChild(child);

          expect(parent.lightDomChildren.length).toEqual(1);
          expect(parent.lightDomChildren[0]).toBe(child);
        });

        it('should add shadow dom children', () => {
          parent.addShadowDomChild(child);

          expect(parent.shadowDomChildren.length).toEqual(1);
          expect(parent.shadowDomChildren[0]).toBe(child);
        });

        it('should remove light dom children', () => {
          parent.addChild(child);
          parent.removeChild(child);

          expect(parent.lightDomChildren).toEqual([]);
        });

        it('should remove shadow dom children', () => {
          parent.addShadowDomChild(child);
          parent.removeShadowDomChild(child);

          expect(parent.shadowDomChildren.length).toEqual(0);
        });
      });

      describe('mode', () => {
        it('should set the mode to CHECK_ALWAYS when the default change detection is used', () => {
          var cd = _createWithoutHydrate('emptyUsingDefaultStrategy').changeDetector;
          expect(cd.mode).toEqual(null);

          cd.hydrate(_DEFAULT_CONTEXT, null, null, null);
          expect(cd.mode).toEqual(CHECK_ALWAYS);
        });

        it('should set the mode to CHECK_ONCE when the push change detection is used', () => {
          var cd = _createWithoutHydrate('emptyUsingOnPushStrategy').changeDetector;
          cd.hydrate(_DEFAULT_CONTEXT, null, null, null);

          expect(cd.mode).toEqual(CHECK_ONCE);
        });

        it('should not check a detached change detector', () => {
          var val = _createChangeDetector('a', new TestData('value'));

          val.changeDetector.hydrate(_DEFAULT_CONTEXT, null, null, null);
          val.changeDetector.mode = DETACHED;
          val.changeDetector.detectChanges();

          expect(val.dispatcher.log).toEqual([]);
        });

        it('should not check a checked change detector', () => {
          var val = _createChangeDetector('a', new TestData('value'));

          val.changeDetector.hydrate(_DEFAULT_CONTEXT, null, null, null);
          val.changeDetector.mode = CHECKED;
          val.changeDetector.detectChanges();

          expect(val.dispatcher.log).toEqual([]);
        });

        it('should change CHECK_ONCE to CHECKED', () => {
          var cd = _createChangeDetector('10').changeDetector;
          cd.hydrate(_DEFAULT_CONTEXT, null, null, null);
          cd.mode = CHECK_ONCE;

          cd.detectChanges();

          expect(cd.mode).toEqual(CHECKED);
        });

        it('should not change the CHECK_ALWAYS', () => {
          var cd = _createChangeDetector('10').changeDetector;
          cd.hydrate(_DEFAULT_CONTEXT, null, null, null);
          cd.mode = CHECK_ALWAYS;

          cd.detectChanges();

          expect(cd.mode).toEqual(CHECK_ALWAYS);
        });

        describe('marking ON_PUSH detectors as CHECK_ONCE after an update', () => {
          var checkedDetector;
          var directives;

          beforeEach(() => {
            checkedDetector = _createWithoutHydrate('emptyUsingOnPushStrategy').changeDetector;
            checkedDetector.hydrate(_DEFAULT_CONTEXT, null, null, null);
            checkedDetector.mode = CHECKED;

            var targetDirective = new TestData(null);
            directives = new FakeDirectives([targetDirective], [checkedDetector]);
          });

          it('should set the mode to CHECK_ONCE when a binding is updated', () => {
            var cd = _createWithoutHydrate('onPushRecordsUsingDefaultStrategy').changeDetector;
            cd.hydrate(_DEFAULT_CONTEXT, null, directives, null);

            expect(checkedDetector.mode).toEqual(CHECKED);

            // evaluate the record, update the targetDirective, and mark its detector as
            // CHECK_ONCE
            cd.detectChanges();

            expect(checkedDetector.mode).toEqual(CHECK_ONCE);
          });
        });
      });

      describe('markPathToRootAsCheckOnce', () => {
        function changeDetector(mode, parent) {
          var val = _createChangeDetector('10');
          val.changeDetector.mode = mode;
          if (isPresent(parent)) parent.addChild(val.changeDetector);
          return val.changeDetector;
        }

        it('should mark all checked detectors as CHECK_ONCE until reaching a detached one', () => {
          var root = changeDetector(CHECK_ALWAYS, null);
          var disabled = changeDetector(DETACHED, root);
          var parent = changeDetector(CHECKED, disabled);
          var checkAlwaysChild = changeDetector(CHECK_ALWAYS, parent);
          var checkOnceChild = changeDetector(CHECK_ONCE, checkAlwaysChild);
          var checkedChild = changeDetector(CHECKED, checkOnceChild);

          checkedChild.markPathToRootAsCheckOnce();

          expect(root.mode).toEqual(CHECK_ALWAYS);
          expect(disabled.mode).toEqual(DETACHED);
          expect(parent.mode).toEqual(CHECK_ONCE);
          expect(checkAlwaysChild.mode).toEqual(CHECK_ALWAYS);
          expect(checkOnceChild.mode).toEqual(CHECK_ONCE);
          expect(checkedChild.mode).toEqual(CHECK_ONCE);
        });
      });

      describe('hydration', () => {
        it('should be able to rehydrate a change detector', () => {
          var cd = _createChangeDetector('name').changeDetector;

          cd.hydrate('some context', null, null, null);
          expect(cd.hydrated()).toBe(true);

          cd.dehydrate();
          expect(cd.hydrated()).toBe(false);

          cd.hydrate('other context', null, null, null);
          expect(cd.hydrated()).toBe(true);
        });

        it('should destroy all active pipes during dehyration', () => {
          var pipe = new OncePipe();
          var registry = new FakePipeRegistry('pipe', () => pipe);
          var cd = _createChangeDetector('name | pipe', new Person('bob'), registry).changeDetector;

          cd.detectChanges();
          cd.dehydrate();

          expect(pipe.destroyCalled).toBe(true);
        });

        it('should throw when detectChanges is called on a dehydrated detector', () => {
          var context = new Person('Bob');
          var val = _createChangeDetector('name', context);

          val.changeDetector.detectChanges();
          expect(val.dispatcher.log).toEqual(['propName=Bob']);

          val.changeDetector.dehydrate();
          var dehydratedException = new DehydratedException();
          expect(() => {val.changeDetector.detectChanges()})
              .toThrowError(dehydratedException.toString());
          expect(val.dispatcher.log).toEqual(['propName=Bob']);
        });
      });

      describe('pipes', () => {
        it('should support pipes', () => {
          var registry = new FakePipeRegistry('pipe', () => new CountingPipe());
          var ctx = new Person('Megatron');

          var val = _createChangeDetector('name | pipe', ctx, registry);

          val.changeDetector.detectChanges();

          expect(val.dispatcher.log).toEqual(['propName=Megatron state:0']);

          val.dispatcher.clear();
          val.changeDetector.detectChanges();

          expect(val.dispatcher.log).toEqual(['propName=Megatron state:1']);
        });

        it('should lookup pipes in the registry when the context is not supported', () => {
          var registry = new FakePipeRegistry('pipe', () => new OncePipe());
          var ctx = new Person('Megatron');

          var cd = _createChangeDetector('name | pipe', ctx, registry).changeDetector;

          cd.detectChanges();

          expect(registry.numberOfLookups).toEqual(1);

          ctx.name = 'Optimus Prime';
          cd.detectChanges();

          expect(registry.numberOfLookups).toEqual(2);
        });

        it('should invoke onDestroy on a pipe before switching to another one', () => {
          var pipe = new OncePipe();
          var registry = new FakePipeRegistry('pipe', () => pipe);
          var ctx = new Person('Megatron');

          var cd = _createChangeDetector('name | pipe', ctx, registry).changeDetector;

          cd.detectChanges();
          ctx.name = 'Optimus Prime';
          cd.detectChanges();

          expect(pipe.destroyCalled).toEqual(true);
        });

        it('should inject the ChangeDetectorRef ' +
               'of the encompassing component into a pipe',
           () => {

             var registry = new FakePipeRegistry('pipe', () => new IdentityPipe());
             var cd =
                 _createChangeDetector('name | pipe', new Person('bob'), registry).changeDetector;

             cd.detectChanges();

             expect(registry.cdRef).toBe(cd.ref);
           });
      });

      it('should do nothing when no change', () => {
        var registry = new FakePipeRegistry('pipe', () => new IdentityPipe());
        var ctx = new Person('Megatron');

        var val = _createChangeDetector('name | pipe', ctx, registry);

        val.changeDetector.detectChanges();

        expect(val.dispatcher.log).toEqual(['propName=Megatron']);

        val.dispatcher.clear();
        val.changeDetector.detectChanges();

        expect(val.dispatcher.log).toEqual([]);
      });

      it('should unwrap the wrapped value', () => {
        var registry = new FakePipeRegistry('pipe', () => new WrappedPipe());
        var ctx = new Person('Megatron');

        var val = _createChangeDetector('name | pipe', ctx, registry);

        val.changeDetector.detectChanges();

        expect(val.dispatcher.log).toEqual(['propName=Megatron']);
      });
    });
  });
}

class CountingPipe implements Pipe {
  state: number = 0;

  onDestroy() {}

  supports(newValue) { return true; }

  transform(value, args = null) { return `${value} state:${this.state ++}`; }
}

class OncePipe implements Pipe {
  called: boolean = false;
  destroyCalled: boolean = false;

  supports(newValue) { return !this.called; }

  onDestroy() { this.destroyCalled = true; }

  transform(value, args = null) {
    this.called = true;
    return value;
  }
}

class IdentityPipe implements Pipe {
  supports(obj): boolean { return true; }

  onDestroy() {}

  transform(value, args = null) { return value; }
}

class WrappedPipe implements Pipe {
  supports(obj): boolean { return true; }

  onDestroy() {}

  transform(value, args = null) { return WrappedValue.wrap(value); }
}

class MultiArgPipe implements Pipe {
  transform(value, args = null) {
    var arg1 = args[0];
    var arg2 = args[1];
    var arg3 = args.length > 2 ? args[2] : 'default';
    return `${value} ${arg1} ${arg2} ${arg3}`;
  }
  supports(obj): boolean { return true; }
  onDestroy(): void {}
}

class FakePipeRegistry extends PipeRegistry {
  numberOfLookups: number;
  pipeType: string;
  factory: Function;
  cdRef: any;

  constructor(pipeType, factory) {
    super({});
    this.pipeType = pipeType;
    this.factory = factory;
    this.numberOfLookups = 0;
  }

  get(type: string, obj, cdRef?, existingPipe?) {
    if (type != this.pipeType) return null;
    this.numberOfLookups++;
    this.cdRef = cdRef;
    return this.factory();
  }
}

class TestDirective {
  a;
  b;
  changes;
  onChangesDoneCalled;
  onChangesDoneSpy;
  onCheckCalled;
  onInitCalled;

  constructor(onChangesDoneSpy = null) {
    this.onChangesDoneCalled = false;
    this.onCheckCalled = false;
    this.onInitCalled = false;
    this.onChangesDoneSpy = onChangesDoneSpy;
    this.a = null;
    this.b = null;
    this.changes = null;
  }

  onCheck() { this.onCheckCalled = true; }

  onInit() { this.onInitCalled = true; }

  onChange(changes) {
    var r = {};
    StringMapWrapper.forEach(changes, (c, key) => r[key] = c.currentValue);
    this.changes = r;
  }

  onAllChangesDone() {
    this.onChangesDoneCalled = true;
    if (isPresent(this.onChangesDoneSpy)) {
      this.onChangesDoneSpy();
    }
  }
}

class Person {
  age: number;
  constructor(public name: string, public address: Address = null) {}

  sayHi(m) { return `Hi, ${m}`; }

  passThrough(val) { return val; }

  toString(): string {
    var address = this.address == null ? '' : ' address=' + this.address.toString();

    return 'name=' + this.name + address;
  }
}

class Address {
  constructor(public city: string) {}

  toString(): string { return isBlank(this.city) ? '-' : this.city }
}

class Uninitialized {
  value: any;
}

class TestData {
  constructor(public a: any) {}
}

class FakeDirectives {
  constructor(public directives: List<TestData | TestDirective>,
              public detectors: List<ProtoChangeDetector>) {}

  getDirectiveFor(di: DirectiveIndex) { return this.directives[di.directiveIndex]; }

  getDetectorFor(di: DirectiveIndex) { return this.detectors[di.directiveIndex]; }
}

class TestDispatcher implements ChangeDispatcher {
  log: List<string>;
  loggedValues: List<any>;
  onAllChangesDoneCalled: boolean = false;

  constructor() { this.clear(); }

  clear() {
    this.log = [];
    this.loggedValues = [];
    this.onAllChangesDoneCalled = true;
  }

  notifyOnBinding(binding, value) {
    this.log.push(`${binding.propertyName}=${this._asString(value)}`);
    this.loggedValues.push(value);
  }

  notifyOnAllChangesDone() { this.onAllChangesDoneCalled = true; }

  _asString(value) { return (isBlank(value) ? 'null' : value.toString()); }
}

class _ChangeDetectorAndDispatcher {
  constructor(public changeDetector: any, public dispatcher: TestDispatcher) {}
}