super.setUp();
    hasher = mock(Hasher.class);
    hashFunction = mock(HashFunction.class);

    when(hashFunction.newHasher()).thenReturn(hasher);
  }

  public void testWrite_putSingleByte() throws Exception {
    int b = 'q';
    HashingOutputStream out = new HashingOutputStream(hashFunction, buffer);
    out.write(b);

    verify(hashFunction).newHasher();
    verify(hasher).putByte((byte) b);