$q promise breaking loop

wtf.spec.js

c = console;
angular.module('Test', []);
    
angular.module('Test').factory('Collection', function($q) {

  var Collection = function()    {var self = this;
    self.__items = {};
    self.__relationships = [];
  };
  var def = Collection.prototype;
  
  def.deleteItem = function(item)    {var self = this;
    c.log('deleting ' + item._id);
    var deferred = $q.defer();
    var childDeletions = self.__relationships.map(function(relationship) {
      return relationship.respondToItemDeleted(item, self);
    });
    $q.all(childDeletions).then(function() {
      delete self.__items[item._id];
      deferred.resolve();
    });
    return deferred.promise;
  };
  return Collection;
});

angular.module('Test').factory('ParentChildRelationship', function($q) {

  var ParentChildRelationship = function(parentCollection, childCollection)    {var self = this;
    self.__parentCollection = parentCollection;
    self.__childCollection = childCollection;
    parentCollection.__relationships.push(self);
    childCollection.__relationships.push(self);
    self.__itemParent = {};
    self.__itemChildren = {};
  };
  var def = ParentChildRelationship.prototype;
  
  def.respondToItemDeleted = function (item, collection)     {var self = this;
    if (collection === self.__parentCollection) {
      return self.__respondToParentDeleted(item);
    } else if (collection === self.__childCollection) {
      return self.__respondToChildDeleted(item);
    }
  };
  
  def.__respondToParentDeleted = function (parentItem)     {var self = this;
    var children = self.__itemChildren[parentItem._id];
    c.log(children.map(function(childItem){return childItem._id}));
    var cascadedActionPromises = children.map(function(childItem) {
      c.log('loop on ' + childItem._id);
      return self.__childCollection.deleteItem(childItem);
    });
    c.log(cascadedActionPromises);
  };
  
  def.__respondToChildDeleted = function (childItem)     {var self = this;
    var parentItem = self.__itemParent[childItem._id];
    //return $q.when(true);   // Doesn't break loop.
    if (parentItem) {
       var myArray = self.__itemChildren[parentItem._id];
       var index = myArray.indexOf(childItem);
       if (index > -1) {
         myArray.splice(index, 1);
       }
    }
    //return $q.when(true);  // DOES break loop.
    delete self.__itemParent[childItem._id];
    return $q.when(true);    // DOES break loop.
  };
  
  return ParentChildRelationship;
});



describe('deleting', function() {

  beforeEach(module('Test'));

  var parentCollection, 
    childCollection, 
    relationship,
    project1 = {_id: 'project1'},
    task1 = {_id: 'task1'},
    task2 = {_id: 'task2'}, 
    task3 = {_id: 'task3'};
    //task4 = {_id: 'task4'},
    //task5 = {_id: 'task5'};
    
  beforeEach(inject(function(_$rootScope_, Collection, ParentChildRelationship) {
    $rootScope = _$rootScope_;
    parentCollection = new Collection();
    childCollection = new Collection();
    
    parentCollection.items = [project1];
    childCollection.items = [task1, task2, task3];
    relationship = new ParentChildRelationship(parentCollection, childCollection);
    relationship.__itemParent[task1._id] = project1;
    relationship.__itemChildren[project1._id] = [task1, task2, task3];
  }));

  fit('delete cascades', function() {

    parentCollection.deleteItem(project1);
    $rootScope.$apply();

  });

});