[WorkItem(191649)] // related bug
public void Composition_MoveChildToNewParent()
{
ConfigurableEntityContainer container = new ConfigurableEntityContainer();
container.CreateSet<Parent>(EntitySetOperations.All);
container.CreateSet<Child>(EntitySetOperations.All);
container.CreateSet<GrandChild>(EntitySetOperations.All);
container.CreateSet<GreatGrandChild>(EntitySetOperations.All);
EntitySet<Parent> parentSet = container.GetEntitySet<Parent>();
EntitySet<Child> childSet = container.GetEntitySet<Child>();
EntitySet<GreatGrandChild> ggChildSet = container.GetEntitySet<GreatGrandChild>();
Parent p1 = new Parent() { ID = 1 };
Parent p2 = new Parent() { ID = 2 };
container.LoadEntities(new Entity[] { p1, new Child { ID = 1, ParentID = 1 }, new Child { ID = 2, ParentID = 1 },
p2, new Child { ID = 3, ParentID = 2 }, new Child { ID = 4, ParentID = 2 } });
Assert.AreEqual(2, p1.Children.Count());
Assert.AreEqual(2, p2.Children.Count());
Child child = p1.Children.ElementAt(0);
p1.Children.Remove(child);
Assert.AreEqual(1, p1.Children.Count());
Assert.AreEqual(2, p2.Children.Count());
// This is the repro - this addition was causing the counts to be 1 and 4 below
p2.Children.Add(child);
Assert.AreEqual(1, p1.Children.Count);
Assert.AreEqual(3, p2.Children.Count);
Assert.AreEqual(EntityState.Modified, child.EntityState);
Assert.AreSame(p2, child.Parent);
}
public void DeleteParent(Parent parent)
{
CompositionHelper.Validate(parent);
SetOperationInvoked(parent);
((CompositionEntityBase)parent).OperationResult = "Delete";
}
public void UpdateParent(Parent parent)
{
// first validate the hierarchy
CompositionHelper.Validate(parent);
((CompositionEntityBase)parent).OperationResult = "Update";
// for an updated, children might be added, updated
// or deleted. We need to enumerate all and act appropriately
foreach (Child child in this.ChangeSet.GetAssociatedChanges(parent, p => p.Children))
{
ChangeOperation changeOp = this.ChangeSet.GetChangeOperation(child);
if (changeOp == ChangeOperation.Insert)
{
((CompositionEntityBase)child).OperationResult = "Insert";
}
else if (changeOp == ChangeOperation.Update)
{
((CompositionEntityBase)child).OperationResult = "Update";
}
else if (changeOp == ChangeOperation.Delete)
{
((CompositionEntityBase)child).OperationResult = "Delete";
}
// now process child updates for the child
foreach (GrandChild grandChild in this.ChangeSet.GetAssociatedChanges(child, p => p.Children))
{
changeOp = this.ChangeSet.GetChangeOperation(grandChild);
if (changeOp == ChangeOperation.Insert)
{
((CompositionEntityBase)grandChild).OperationResult = "Insert";
}
else if (changeOp == ChangeOperation.Update)
{
((CompositionEntityBase)grandChild).OperationResult = "Update";
}
else if (changeOp == ChangeOperation.Delete)
{
((CompositionEntityBase)grandChild).OperationResult = "Delete";
}
// finally, process any great grand child updates
GreatGrandChild updatedGreateGrandChild = this.ChangeSet.GetAssociatedChanges(grandChild, p => p.Child).Cast<GreatGrandChild>().SingleOrDefault();
if (updatedGreateGrandChild != null)
{
changeOp = this.ChangeSet.GetChangeOperation(updatedGreateGrandChild);
if (changeOp == ChangeOperation.Insert)
{
((CompositionEntityBase)updatedGreateGrandChild).OperationResult = "Insert";
}
else if (changeOp == ChangeOperation.Update)
{
((CompositionEntityBase)updatedGreateGrandChild).OperationResult = "Update";
}
else if (changeOp == ChangeOperation.Delete)
{
((CompositionEntityBase)updatedGreateGrandChild).OperationResult = "Delete";
}
}
}
}
}
public void InsertParent(Parent parent)
{
// first validate the hierarchy
CompositionHelper.Validate(parent);
((CompositionEntityBase)parent).OperationResult = "Insert";
// for a new parent, all children will also be new
// so we enumerate all and "add" them
foreach (Child child in parent.Children)
{
((CompositionEntityBase)child).OperationResult = "Insert";
foreach (GrandChild grandChild in child.Children)
{
((CompositionEntityBase)grandChild).OperationResult = "Insert";
GreatGrandChild greatGrandChild = grandChild.Child;
if (greatGrandChild != null)
{
((CompositionEntityBase)greatGrandChild).OperationResult = "Insert";
}
}
}
}
/// <summary>
/// Use the changeset composition APIs to navigate all child updates
/// </summary>
/// <param name="parent"></param>
private void NavigateChildChanges(Parent parent)
{
// if the parent has had property modifications, original will
// be non-null
if (this.ChangeSet.GetChangeOperation(parent) != ChangeOperation.Insert)
{
Parent originalParent = this.ChangeSet.GetOriginal(parent);
}
// navigate all child changes w/o specifying operation type
Dictionary<object, ChangeOperation> changeOperationMap = new Dictionary<object, ChangeOperation>();
foreach (Child child in this.ChangeSet.GetAssociatedChanges(parent, p => p.Children))
{
ChangeOperation op = this.ChangeSet.GetChangeOperation(child);
changeOperationMap[child] = op;
if (this.ChangeSet.GetChangeOperation(child) != ChangeOperation.Insert)
{
Child originalChild = this.ChangeSet.GetOriginal(child);
}
if (op == ChangeOperation.None)
{
}
else if (op == ChangeOperation.Insert)
{
CompositionHelper.Assert(this.ChangeSet.ChangeSetEntries.SingleOrDefault(p => p.Entity == child && p.Operation == DomainOperation.Insert) != null,
"Expected corresponding insert operation not found.");
}
else if (op == ChangeOperation.Update)
{
CompositionHelper.Assert(this.ChangeSet.ChangeSetEntries.SingleOrDefault(p => p.Entity == child && p.Operation == DomainOperation.Update) != null,
"Expected corresponding update operation not found.");
}
else if (op == ChangeOperation.Delete)
{
CompositionHelper.Assert(this.ChangeSet.ChangeSetEntries.SingleOrDefault(p => p.Entity == child && p.Operation == DomainOperation.Delete) != null,
"Expected corresponding delete operation not found.");
}
foreach (GrandChild grandChild in this.ChangeSet.GetAssociatedChanges(child, p => p.Children))
{
changeOperationMap[grandChild] = this.ChangeSet.GetChangeOperation(grandChild);
foreach (GreatGrandChild greatGrandChild in this.ChangeSet.GetAssociatedChanges(grandChild, p => p.Child))
{
changeOperationMap[greatGrandChild] = this.ChangeSet.GetChangeOperation(greatGrandChild);
}
}
}
// verify all child operations against the map we built up during enumeration
// of associated changes to ensure all operations were returned
foreach (ChangeSetEntry operation in this.ChangeSet.ChangeSetEntries.Where(p => p.Entity.GetType() != typeof(Parent)))
{
switch (operation.Operation)
{
case DomainOperation.Insert:
CompositionHelper.Assert(changeOperationMap.ContainsKey(operation.Entity) &&
changeOperationMap[operation.Entity] == ChangeOperation.Insert,
"Expected insert operation was not returned from GetAssociatedChanges.");
break;
case DomainOperation.Update:
CompositionHelper.Assert(changeOperationMap.ContainsKey(operation.Entity) &&
changeOperationMap[operation.Entity] == ChangeOperation.Update,
"Expected update operation was not returned from GetAssociatedChanges.");
break;
case DomainOperation.Delete:
CompositionHelper.Assert(
changeOperationMap.ContainsKey(operation.Entity) &&
changeOperationMap[operation.Entity] == ChangeOperation.Delete,
"Expected delete operation was not returned from GetAssociatedChanges.");
break;
}
}
// navigate all child changes specifying operation type
foreach (Child child in this.ChangeSet.GetAssociatedChanges(parent, p => p.Children, ChangeOperation.None))
{
}
foreach (Child child in this.ChangeSet.GetAssociatedChanges(parent, p => p.Children, ChangeOperation.Insert))
{
}
foreach (Child child in this.ChangeSet.GetAssociatedChanges(parent, p => p.Children, ChangeOperation.Update))
{
}
foreach (Child child in this.ChangeSet.GetAssociatedChanges(parent, p => p.Children, ChangeOperation.Delete))
{
}
}
public void Composition_AddChildPreviouslyReferencingOtherParent()
{
ConfigurableEntityContainer container = new ConfigurableEntityContainer();
container.CreateSet<Parent>(EntitySetOperations.All);
container.CreateSet<Child>(EntitySetOperations.All);
container.CreateSet<GrandChild>(EntitySetOperations.All);
container.CreateSet<GreatGrandChild>(EntitySetOperations.All);
EntitySet<Parent> parentSet = container.GetEntitySet<Parent>();
EntitySet<Child> childSet = container.GetEntitySet<Child>();
EntitySet<GreatGrandChild> ggChildSet = container.GetEntitySet<GreatGrandChild>();
Parent p1 = new Parent() { ID = 1 };
Parent p2 = new Parent() { ID = 2 };
container.LoadEntities(new Entity[] { p1, p2 });
Child child = new Child() { ID = 1, ParentID = 2 };
p1.Children.Add(child);
Assert.AreEqual(EntityState.Modified, p1.EntityState);
Assert.IsTrue(childSet.HasChanges);
}
public static void Validate(Parent parent)
{
// Simulate a validation pass that enumerates all children.
foreach (Child child in parent.Children)
{
foreach (GrandChild grandChild in child.Children)
{
GreatGrandChild greatGrandChild = grandChild.Child;
}
}
}
public void CustomOp_Parent(Parent parent)
{
CompositionHelper.Validate(parent);
this.SetOperationInvoked(parent, "CustomOp_Parent");
((CompositionEntityBase)parent).OperationResult += ",CustomOp_Parent";
}
public void Composition_ParentUpdateOnDelete()
{
ConfigurableEntityContainer container = new ConfigurableEntityContainer();
container.CreateSet<Parent>(EntitySetOperations.All);
container.CreateSet<Child>(EntitySetOperations.All);
container.CreateSet<GrandChild>(EntitySetOperations.All);
EntitySet<Parent> parentSet = container.GetEntitySet<Parent>();
EntitySet<Child> childSet = container.GetEntitySet<Child>();
Parent parent1 = new Parent() { ID = 1 };
Child child1 = new Child() { ID = 1, Parent = parent1 };
container.LoadEntities(new Entity[] { parent1, child1 });
// insert new parent and child
Parent newParent = new Parent();
Child newChild = new Child();
newChild.Parent = newParent;
parentSet.Add(newParent);
// When the parent is removed, all it's children are also removed.
// This causes the child ParentID to be set to 0, which means it now
// matches the new Parent.Children collection. The removed child is added to
// the new parent's collection, which causes child.Parent to be updated.
// However that add is transitory - once the child is removed from the
// entity set, it is removed from the new entity's child collection.
// That invalid update will result in an exception on submit.
parentSet.Remove(parent1);
Assert.AreEqual(1, newParent.Children.Count);
Assert.IsTrue(newParent.Children.Contains(newChild));
// if we allow the transitory phase, on accept changes we have to be
// sure things are fixed up
Assert.AreEqual(EntityState.Deleted, parent1.EntityState);
Assert.AreEqual(EntityState.Deleted, child1.EntityState);
Assert.AreSame(newParent, newChild.Parent);
// changeset validation succeeds, since the parent is deleted along
// with the child
EntityChangeSet changeSet = container.GetChanges();
Assert.IsTrue(changeSet.AddedEntities.Count == 2 && changeSet.RemovedEntities.Count == 2);
ChangeSetBuilder.CheckForInvalidUpdates(changeSet);
}
public void Composition_InvalidParentUpdate_EntityCollection()
{
ConfigurableEntityContainer container = new ConfigurableEntityContainer();
container.CreateSet<Parent>(EntitySetOperations.All);
container.CreateSet<Child>(EntitySetOperations.All);
container.CreateSet<GrandChild>(EntitySetOperations.All);
EntitySet<Parent> parentSet = container.GetEntitySet<Parent>();
EntitySet<Child> childSet = container.GetEntitySet<Child>();
Parent parent1 = new Parent() { ID = 1 };
Parent parent2 = new Parent() { ID = 2 };
Child child = new Child() { ID = 1, Parent = parent1 };
parentSet.Attach(parent1);
parentSet.Attach(parent2);
Assert.IsTrue(childSet.IsAttached(child), "Child was not attached automatically.");
Assert.AreSame(parent1, ((Entity)child).Parent, "Entity.Parent doesn't reflect the parent-child relationship.");
// point the child to a new parent, which results
// in the child being reparented (an invalid update)
child.Parent = parent2;
EntityChangeSet changeSet = container.GetChanges();
Assert.AreEqual(EntityState.Modified, child.EntityState);
Assert.AreEqual(EntityState.Modified, parent1.EntityState);
Assert.AreEqual(EntityState.Modified, parent2.EntityState);
// Verify that changing the parent throws an exception when
// changes are validated
ExceptionHelper.ExpectInvalidOperationException(delegate
{
ChangeSetBuilder.CheckForInvalidUpdates(changeSet);
}, string.Format(Resource.Entity_CantReparentComposedChild, child));
}
public void Composition_MultipleRemoveReadds()
{
ConfigurableEntityContainer container = new ConfigurableEntityContainer();
container.CreateSet<Parent>(EntitySetOperations.All);
container.CreateSet<Child>(EntitySetOperations.All);
container.CreateSet<GrandChild>(EntitySetOperations.All);
container.CreateSet<GreatGrandChild>(EntitySetOperations.All);
EntitySet<Parent> parentSet = container.GetEntitySet<Parent>();
EntitySet<Child> childSet = container.GetEntitySet<Child>();
EntitySet<GreatGrandChild> ggChildSet = container.GetEntitySet<GreatGrandChild>();
Parent parent = new Parent() { ID = 1 };
Child child = new Child() { ID = 1, Parent = parent };
container.LoadEntities(new Entity[] { parent, child });
parent.Children.Remove(child);
Assert.AreEqual(EntityState.Deleted, child.EntityState);
Assert.IsFalse(childSet.Contains(child));
parent.Children.Add(child);
Assert.AreEqual(EntityState.Modified, child.EntityState);
Assert.IsTrue(childSet.Contains(child));
parent.Children.Remove(child);
Assert.AreEqual(EntityState.Deleted, child.EntityState);
Assert.IsFalse(childSet.Contains(child));
// verify the same scenario for a singleton composition
GrandChild gc = new GrandChild { ID = 1 };
GreatGrandChild ggc = new GreatGrandChild { ID = 1, ParentID = 1 };
container.LoadEntities(new Entity[] { gc, ggc });
Assert.AreSame(ggc, gc.Child);
gc.Child = null;
Assert.AreEqual(EntityState.Deleted, ggc.EntityState);
Assert.IsFalse(ggChildSet.Contains(ggc));
gc.Child = ggc;
Assert.AreEqual(EntityState.Unmodified, ggc.EntityState);
Assert.IsTrue(ggChildSet.Contains(ggc));
gc.Child = null;
Assert.AreEqual(EntityState.Deleted, ggc.EntityState);
Assert.IsFalse(ggChildSet.Contains(ggc));
}
/// <summary>
/// Verify that each node in the hierarchy has the expected children
/// and all Parent back pointers are valid.
/// </summary>
private static void VerifyHierarchy(Parent parent)
{
Assert.IsTrue(parent.Children.Count > 0);
foreach (Child c in parent.Children)
{
Assert.AreSame(parent, c.Parent);
Assert.IsTrue(c.Children.Count > 0);
foreach (GrandChild gc in c.Children)
{
Assert.AreSame(c, gc.Parent);
if (gc.Child != null)
{
Assert.AreSame(gc, gc.Child.Parent);
}
}
}
}
private static Parent CreateCompositionHierarchy(int numChildren, int numGrandChildren)
{
int parentKey = 1;
int childKey = 1;
int grandChildKey = 1;
int greatGrandChildKey = 1;
Parent p = new Parent
{
ID = parentKey++
};
for (int j = 0; j < numChildren; j++)
{
Child c = new Child
{
ID = childKey++, ParentID = p.ID, Parent = p
};
p.Children.Add(c);
for (int k = 0; k < numGrandChildren; k++)
{
GrandChild gc = new GrandChild
{
ID = grandChildKey++, ParentID = c.ID, Parent = c
};
c.Children.Add(gc);
// add singleton child to grand child
gc.Child = new GreatGrandChild
{
ID = greatGrandChildKey++, ParentID = gc.ID, Parent = gc
};
}
}
VerifyHierarchy(p);
return p;
}
public void DeleteParent(Parent parent)
{
// normally you wouldn't validate a deleted hierarchy,
// but we do it here for test validation
CompositionHelper.Validate(parent);
((CompositionEntityBase)parent).OperationResult = "Delete";
// Delete all children in the hierarchy.
foreach (Child child in parent.Children)
{
foreach (GrandChild grandChild in child.Children)
{
GreatGrandChild greatGrandChild = grandChild.Child;
if (greatGrandChild != null)
{
}
}
}
}
public void Entity_RemoveParent()
{
ConfigurableEntityContainer container = new ConfigurableEntityContainer();
container.CreateSet<Parent>(EntitySetOperations.All);
container.CreateSet<Child>(EntitySetOperations.All);
container.CreateSet<GrandChild>(EntitySetOperations.All);
EntitySet<Parent> parentSet = container.GetEntitySet<Parent>();
EntitySet<Child> childSet = container.GetEntitySet<Child>();
Parent parent1 = new Parent() { ID = 1 };
Parent parent2 = new Parent() { ID = 2 };
Child child = new Child() { ID = 1, Parent = parent1 };
parentSet.Attach(parent1);
parentSet.Attach(parent2);
Assert.IsTrue(childSet.IsAttached(child), "Child was not attached automatically.");
Assert.AreSame(parent1, ((Entity)child).Parent, "Entity.Parent doesn't reflect the parent-child relationship.");
parentSet.Remove(parent1);
EntityChangeSet changeSet = container.GetChanges();
Assert.AreEqual(2, changeSet.Count());
}
public void CustomOp_Parent(Parent parent)
{
// first validate the hierarchy
CompositionHelper.Validate(parent);
((CompositionEntityBase)parent).OperationResult += ",CustomOp_Parent";
}
private bool FilterParent(Parent entity)
{
return (entity.ID == this.ParentID);
}
public void CustomParentUpdate(Parent parent)
{
}
/// <summary>
/// Invokes the 'CustomOp_Parent' method of the specified <see cref="Parent"/> entity.
/// </summary>
/// <param name="parent">The <see cref="Parent"/> entity instance.</param>
public void CustomOp_Parent(Parent parent)
{
parent.CustomOp_Parent();
}
/// <summary>
/// Create a 4 level compositional hierarchy that includes both
/// collection and singleton compositions
/// </summary>
public static List<Parent> CreateCompositionHierarchy()
{
int parentKey = 1;
int childKey = 1;
int grandChildKey = 1;
int greatGrandChildKey = 1;
List<Parent> parents = new List<Parent>();
for (int i = 0; i < 3; i++)
{
Parent p = new Parent
{
ID = parentKey++
};
parents.Add(p);
for (int j = 0; j < 3; j++)
{
Child c = new Child
{
ID = childKey++, ParentID = p.ID, Parent = p
};
p.Children.Add(c);
for (int k = 0; k < 3; k++)
{
GrandChild gc = new GrandChild
{
ID = grandChildKey++, ParentID = c.ID, Parent = c
};
c.Children.Add(gc);
// add singleton child to grand child
gc.Child = new GreatGrandChild
{
ID = greatGrandChildKey++, ParentID = gc.ID, Parent = gc
};
}
}
}
return parents;
}
public void Changeset_GetAssociatedChanges_Enumerable()
{
DomainServiceDescription dsd = DomainServiceDescription.GetDescription(typeof(CompositionScenarios_Explicit));
#region build up a compositional hierarchy
int id = 1;
Parent currParent = new Parent();
List<ChangeSetEntry> changeSetEntries = new List<ChangeSetEntry>();
ChangeSetEntry parentUpdateOperation = new ChangeSetEntry(id++, currParent, null, DomainOperation.Update);
List<int> currentAssociatedChildren = new List<int>();
changeSetEntries.Add(parentUpdateOperation);
// add 3 unmodified children
List<Child> unmodifiedChildren = new List<Child>() { new Child(), new Child(), new Child() };
foreach (Child c in unmodifiedChildren)
{
ChangeSetEntry operation = new ChangeSetEntry(id++, c, c, DomainOperation.None);
changeSetEntries.Add(operation);
currParent.Children.Add(c);
currentAssociatedChildren.Add(operation.Id);
}
// add 2 child edits
List<Child> originalEditedChildren = new List<Child> { new Child(), new Child() };
List<Child> currentEditedChildren = new List<Child> { new Child(), new Child() };
for (int i = 0; i < originalEditedChildren.Count; i++)
{
Child currChild = currentEditedChildren[i];
Child origChild = originalEditedChildren[i];
ChangeSetEntry operation = new ChangeSetEntry(id++, currChild, origChild, DomainOperation.Update);
changeSetEntries.Add(operation);
currParent.Children.Add(currChild);
currentAssociatedChildren.Add(operation.Id);
}
// add a 2 new children children
List<Child> newChildren = new List<Child> { new Child(), new Child() };
foreach (Child c in newChildren)
{
ChangeSetEntry operation = new ChangeSetEntry(id++, c, null, DomainOperation.Insert);
changeSetEntries.Add(operation);
currParent.Children.Add(c);
currentAssociatedChildren.Add(operation.Id);
}
// add 2 removes by adding operations for the deleted children
// and setting up the original association
List<Child> removedChildren = new List<Child> { new Child(), new Child() };
List<int> deletedChildren = new List<int>();
foreach (Child c in removedChildren)
{
int deletedId = id++;
changeSetEntries.Add(new ChangeSetEntry(deletedId, c, c, DomainOperation.Delete));
deletedChildren.Add(deletedId);
}
parentUpdateOperation.OriginalAssociations = new Dictionary<string, int[]>() { { "Children", deletedChildren.ToArray() } };
parentUpdateOperation.Associations = new Dictionary<string, int[]>() { { "Children", currentAssociatedChildren.ToArray() } };
#endregion
// verify unmodified children
ChangeSet cs = new ChangeSet(changeSetEntries);
IEnumerable<Child> childChanges = cs.GetAssociatedChanges(currParent, p => p.Children, ChangeOperation.None).Cast<Child>();
Assert.AreEqual(3, childChanges.Count());
foreach (Child c in childChanges)
{
Assert.IsTrue(unmodifiedChildren.Contains(c));
}
// verify inserted children
childChanges = cs.GetAssociatedChanges(currParent, p => p.Children, ChangeOperation.Insert).Cast<Child>();
Assert.AreEqual(2, childChanges.Count());
foreach (Child c in childChanges)
{
Assert.IsTrue(newChildren.Contains(c));
}
// verify deleted children
childChanges = cs.GetAssociatedChanges(currParent, p => p.Children, ChangeOperation.Delete).Cast<Child>();
Assert.AreEqual(2, childChanges.Count());
foreach (Child c in childChanges)
{
Assert.IsTrue(removedChildren.Contains(c));
}
// verify modified children
childChanges = cs.GetAssociatedChanges(currParent, p => p.Children, ChangeOperation.Update).Cast<Child>();
Assert.AreEqual(2, childChanges.Count());
foreach (Child c in childChanges)
{
Assert.IsTrue(currentEditedChildren.Contains(c));
}
// verify overload that returns all - should return all unmodified
// in addition to all changed
IEnumerable<Child> allChildren = cs.GetAssociatedChanges(currParent, p => p.Children).Cast<Child>();
Assert.AreEqual(9, allChildren.Count());
foreach (Child c in allChildren)
{
ChangeOperation operationType = cs.GetChangeOperation(c);
switch (operationType)
{
case ChangeOperation.None:
Assert.IsTrue(unmodifiedChildren.Contains(c));
break;
case ChangeOperation.Insert:
Assert.IsTrue(newChildren.Contains(c));
break;
case ChangeOperation.Update:
Assert.IsTrue(currentEditedChildren.Contains(c));
break;
case ChangeOperation.Delete:
Assert.IsTrue(removedChildren.Contains(c));
break;
};
}
// verify calls that return empty
cs = new ChangeSet(new ChangeSetEntry[] { new ChangeSetEntry(1, currParent, null, DomainOperation.None) });
IEnumerable<Child> children = cs.GetAssociatedChanges(currParent, p => p.Children).Cast<Child>();
Assert.AreEqual(0, children.Count());
children = cs.GetAssociatedChanges(currParent, p => p.Children).Cast<Child>();
Assert.AreEqual(0, children.Count());
// test null collection properties
currParent = new Parent { Children = null };
cs = new ChangeSet(new ChangeSetEntry[] { new ChangeSetEntry(1, currParent, new Parent { Children = null }, DomainOperation.None) });
Assert.AreEqual(0, cs.GetAssociatedChanges(currParent, p => p.Children).Cast<Child>().Count());
Assert.AreEqual(0, cs.GetAssociatedChanges(currParent, p => p.Children, ChangeOperation.None).Cast<Child>().Count());
}