this test now fails. previously the test in ChildTest just added a child to a collection that did not have that child.

if i comment out adding the new child, child-a gets deleted as expected. but with this code, my repo does not execute the removal of child-a, but instead keep it with old data, and add the new node as "'0" (because of the index i guess). afaik having the correct index is not mandatory. and anyways it should not prevent deletion.