testDecodes(base64(), "Zg=", "f");
    testDecodes(base64(), "Zg==", "f"); // proper padding length
    testDecodes(base64(), "Zg===", "f");
    testDecodes(base64(), "Zg====", "f");
  }

  public void testBase64InvalidDecodings() {
    // These contain bytes not in the decodabet.
    assertFailsToDecode(base64(), "A\u007f", "Unrecognized character: 0x7f");
    assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");