### Question:
RepositoryDoc implements ApiOperation { public Map<String, PushItem> getChildIds() { return ImmutableMap.copyOf(Maps.transformValues(childIds, PushItem::clone)); } private  RepositoryDoc(Builder builder); Item getItem(); AbstractInputStreamContent getContent(); String getContentHash(); ContentFormat getContentFormat(); Map<String, PushItem> getChildIds(); Map<String, Acl> getFragments(); RequestMode getRequestMode(); @Override List<GenericJson> execute(IndexingService service); @Override int hashCode(); @Override boolean equals(Object other); @Override String toString();  }### Answer:
@Test public void testGetChildIds() { RepositoryDoc doc = new RepositoryDoc.Builder() .setItem(new Item().setName("doc")) .addChildId("id1", new PushItem().setQueue("somewhere")) .addChildId( "id2", new PushItem().setRepositoryError(new RepositoryError().setErrorMessage("drat"))) .build(); Map<String, PushItem> childIds = doc.getChildIds(); assertEquals(childIds, doc.getChildIds()); childIds.get("id1").setQueue("foo"); assertNotEquals(childIds, doc.getChildIds()); thrown.expect(UnsupportedOperationException.class); childIds.put("id3", new PushItem()); }