### Question:
WroModel { public WroModel addGroup(final Group group) { Validate.notNull(group); groups.add(group); return this; }  final Collection<Group> getGroups(); final WroModel setGroups(final Collection<Group> groups); @Deprecated Collection<String> getGroupNamesContainingResource(final String resourceUri); @Deprecated Group getGroupByName(final String name); void merge(final WroModel importedModel); WroModel addGroup(final Group group); @Override boolean equals(final Object obj); @Override int hashCode(); @Override String toString();  }### Answer:
@Test public void shouldNotReturnDuplicatedResources() { final WroModel model = new WroModel(); assertEquals(0, new WroModelInspector(model).getAllUniqueResources().size()); model.addGroup(new Group("one").addResource(Resource.create("/one.js"))).addGroup( new Group("two").addResource(Resource.create("/one.js"))); assertEquals(1, new WroModelInspector(model).getAllUniqueResources().size()); }