More tests:

-fixed bug in EntityManger.addComponents
-added many new tests

source/ecs/manager.d

@@ -2085,6 +2085,7 @@ export struct EntityManager
             {
                 num--;
                 new_ids[i] = new_ids[num];
+                data_pointers[i] = data_pointers[num];
             }
         }
 
@@ -2558,6 +2559,7 @@ export struct EntityManager
                         pointers[i] = &thread.change_entities_list[index];
                         index += components[ids[i]].size;
                     }
+                    
                     __addComponents(id, ids, pointers[0 .. num]);
                 }
             }