/**
   * Persists a given instance and prove if this was properly done.
   *
   * @throws org.rdform.api.context.PersistenceException if this exception occurs then this test
   *     will fails.
   */
  @Test
  public void testPersist() throws PersistenceException {
    final SimpleModel toPersist = new SimpleModel("Mopuffus", "Lumpkins", 38);

    final URI aboutBeforePersist = toPersist.getAbout();
    // for a fresh instance the about must be null.
    assertNull(aboutBeforePersist);

    // here the instance becomes managed (but not persisted)
    persistenceContext.persist(toPersist);

    final boolean mangedBeforeFlush = persistenceContext.isManged(toPersist);
    // the instance is managed but not persisted
    assertTrue(mangedBeforeFlush);

    final boolean wasPersistedBeforeFlush = persistenceContext.wasPersisted(toPersist);
    // the instance is managed but not persisted
    assertFalse(wasPersistedBeforeFlush);

    persistenceContext.flush();

    final URI about = toPersist.getAbout();
    // after persistence the about property gets set to a non-null
    // (generated URI)
    assertNotNull(about);

    final boolean mangedAfterFlush = persistenceContext.isManged(toPersist);
    // the context is/was flushed there are no more managed instances
    assertFalse(mangedAfterFlush);

    final boolean wasPersisted = persistenceContext.wasPersisted(toPersist);
    assertTrue(wasPersisted);
  }
  @Test
  public void testPersistGet() throws PersistenceException {
    final SimpleModel toPersist = new SimpleModel("Mopuffus", "Lumpkins", 38);
    persistenceContext.persist(toPersist);
    persistenceContext.flush();

    final URI about = toPersist.getAbout();
    final Object o = persistenceContext.get(about);
  }