out.write(buf);

    verify(hashFunction).newHasher();
    verify(hasher).putBytes(buf, 0, buf.length);
    verifyNoMoreInteractions(hashFunction, hasher);
  }

  public void testWrite_putByteArrayAtPos() throws Exception {
    byte[] buf = new byte[] {'y', 'a', 'm', 's'};
    HashingOutputStream out = new HashingOutputStream(hashFunction, buffer);
    out.write(buf, 0, 3);

    verify(hashFunction).newHasher();