// that depends on ptest. And so on, up the dependency tree.
	testCopy := map[*Package]*Package{preal: ptest}
	for _, p := range PackageList([]*Package{pmain}) {
		if p == preal {
			continue
		}
		// Copy on write.
		didSplit := p == pmain || p == pxtest || p == ptest
		split := func() {
			if didSplit {
				return
			}
			didSplit = true
			if testCopy[p] != nil {
				panic("recompileForTest loop")
			}

    for (int i = 0; i < 100; i++) {
      Object o = new Object();
      bf.put(o);
      assertTrue(bf.mightContain(o));
      assertTrue(bf.apply(o));
    }
  }

  public void testCopy() {
    BloomFilter<String> original = BloomFilter.create(Funnels.unencodedCharsFunnel(), 100);
    BloomFilter<String> copy = original.copy();
    assertNotSame(original, copy);
    assertEquals(original, copy);
  }