@Test(expected = YardException.class)
 public void testStoreOnReadOnlyYard() throws YardException {
   RdfRepresentation rep =
       RdfValueFactory.getInstance().createRepresentation("http://www.test.org/addedEntity");
   rep.addReference(RDF.type.getUnicodeString(), SKOS.Concept.getUnicodeString());
   rep.addNaturalText(SKOS.prefLabel.getUnicodeString(), "added Entity", "en");
   rep.addNaturalText(SKOS.prefLabel.getUnicodeString(), "hinzugefüte Entity", "de");
   readonlyYard.store(rep);
 }
 /**
  * Used by {@link #testRetrival()} to validate that an Entity is correctly retrieved by the tested
  * {@link ClerezzaYard}s.
  *
  * @param entity key - URI; value - expected RDF data
  */
 private void validateEntity(ClerezzaYard yard, Entry<UriRef, TripleCollection> entity) {
   Representation rep = yard.getRepresentation(entity.getKey().getUnicodeString());
   assertNotNull(
       "The Representation for " + entity.getKey() + "is missing in the " + yard.getId(), rep);
   assertTrue("RdfRepresentation expected", rep instanceof RdfRepresentation);
   TripleCollection repGraph = ((RdfRepresentation) rep).getRdfGraph();
   for (Iterator<Triple> triples = entity.getValue().iterator(); triples.hasNext(); ) {
     Triple triple = triples.next();
     assertTrue(
         "Data of Representation " + entity.getKey() + "is missing the triple " + triple,
         repGraph.remove(triple));
   }
   assertTrue(
       repGraph.size()
           + " unexpected Triples are present in the "
           + "Representation of Entity "
           + entity.getKey(),
       repGraph.isEmpty());
 }
  @Test
  public void testModificationsOnReadWirteYard() throws YardException {
    RdfRepresentation rep =
        RdfValueFactory.getInstance().createRepresentation("http://www.test.org/addedEntity");
    rep.addReference(RDF.type.getUnicodeString(), SKOS.Concept.getUnicodeString());
    rep.addNaturalText(SKOS.prefLabel.getUnicodeString(), "added Entity", "en");
    rep.addNaturalText(SKOS.prefLabel.getUnicodeString(), "hinzugefüte Entity", "de");

    readwriteYard.store(rep);
    // test that the data where added and modified in the read/wirte grpah
    validateEntity(
        readwriteYard, singletonMap(rep.getNode(), rep.getRdfGraph()).entrySet().iterator().next());
    readwriteYard.remove(rep.getId());
    Assert.assertNull(
        "Representation "
            + rep.getId()
            + " was not correctly "
            + "deleted from "
            + readwriteYard.getId(),
        readwriteYard.getRepresentation(rep.getId()));
  }
 @Test(expected = YardException.class)
 public void testRemovalOnReadOnlyYard() throws YardException {
   readonlyYard.remove(entityData.keySet().iterator().next().getUnicodeString());
 }