when(oldInfo.getPersistenceUnitRootUrl()).thenReturn(new URL("file:foo"));
MutablePersistenceUnitInfo newInfo = new MutablePersistenceUnitInfo();
newInfo.setPersistenceUnitRootUrl(new URL("file:bar"));
newInfo.addJarFileUrl(oldInfo.getPersistenceUnitRootUrl());
MergingPersistenceUnitManager manager = new MergingPersistenceUnitManager();
manager.postProcessPersistenceUnitInfo(newInfo, oldInfo);
assertThat(newInfo.getJarFileUrls().size(), is(1));