processCalled--; // don't count the tail invocation (makes tests a bit more understandable)
    }

    // ensures that the number of invocations looks sane
    void assertInvariants(int expectedBytes) {
      // we should have seen as many bytes as the next multiple of chunk after expectedBytes - 1
      assertEquals(out.toByteArray().length, ceilToMultiple(expectedBytes, chunkSize));

        }
      }
    }
  }

  /**
   * Checks that a Hasher returns the same HashCode when given the same input, and also that the
   * collision rate looks sane.
   */
  static void assertInvariants(HashFunction hashFunction) {
    int objects = 100;
    Set<HashCode> hashcodes = Sets.newHashSetWithExpectedSize(objects);
    Random random = new Random(314159);

        }
      }
    }
  }

  /**
   * Checks that a Hasher returns the same HashCode when given the same input, and also that the
   * collision rate looks sane.
   */
  static void assertInvariants(HashFunction hashFunction) {
    int objects = 100;
    Set<HashCode> hashcodes = Sets.newHashSetWithExpectedSize(objects);
    Random random = new Random(314159);