public void testNoGenerations() {
   final BerkeleyDBTempTargetRepository targets = createTempTargetRepository();
   try {
     assertNull(targets.getOldGeneration(0));
     assertNull(targets.getNewGeneration(0));
     assertFalse(targets.copyOldToNewGeneration(0, new ArrayList<Long>()));
     targets.nextGeneration();
   } finally {
     targets.stop();
   }
 }
 public void testRotation() {
   final BerkeleyDBTempTargetRepository targets = createTempTargetRepository();
   try {
     assertEquals(targets.locateOrStoreImpl(new MockTempTarget("Foo")), UniqueId.of("Tmp", "0"));
     final long t = System.nanoTime();
     assertEquals(targets.locateOrStoreImpl(new MockTempTarget("Bar")), UniqueId.of("Tmp", "1"));
     assertTrue(targets.copyOldToNewGeneration(0, new ArrayList<Long>()));
     targets.nextGeneration();
     assertEquals(targets.locateOrStoreImpl(new MockTempTarget("Cow")), UniqueId.of("Tmp", "2"));
     assertTrue(targets.copyOldToNewGeneration(t, new ArrayList<Long>()));
     targets.nextGeneration();
     assertNull(targets.getOldGeneration(0));
     assertEquals(targets.getOldGeneration(1), new MockTempTarget("Bar"));
     assertEquals(targets.getOldGeneration(2), new MockTempTarget("Cow"));
   } finally {
     targets.stop();
   }
 }