@Test
public void testSubtract() throws Exception {

  QuotaCounts qc1 = new QuotaCounts.Builder().build();
  QuotaCounts qc2 = new QuotaCounts.Builder().nameSpace(1).storageSpace(512)
      .typeSpaces(5).build();
  qc1.subtract(qc2);
  assertEquals(-1, qc1.getNameSpace());
  assertEquals(-512, qc1.getStorageSpace());
  for (StorageType type : StorageType.values()) {
    assertEquals(-5, qc1.getTypeSpace(type));
  }
}