### Question:
CodeVerifier { public static boolean matched(String codeChallenge, String codeChallengeMethod, String codeVerifier) { return matched(codeChallenge, CodeChallengeMethod.fromString(codeChallengeMethod), codeVerifier); } CodeVerifier();  CodeVerifier(CodeChallengeMethod transformationType); static String generateCodeChallenge(CodeChallengeMethod codeChallengeMethod, String codeVerifier); static boolean matched(String codeChallenge, String codeChallengeMethod, String codeVerifier); static boolean matched(String codeChallenge, CodeChallengeMethod codeChallengeMethod, String codeVerifier); static String s256(String codeVerifier); static String base64UrlEncode(byte[] input); static String generateCodeVerifier(); static boolean isCodeVerifierValid(String codeVerifier); String getCodeChallenge(); String getCodeVerifier(); CodeChallengeMethod getTransformationType(); @Override String toString();  }### Answer:
@Test public void verifierAndChallengeMatch() throws NoSuchAlgorithmException, UnsupportedEncodingException { assertMatch(CodeVerifier.CodeChallengeMethod.PLAIN); assertMatch(CodeVerifier.CodeChallengeMethod.S256); assertFalse(CodeVerifier.matched(null, "", "invalid_code")); }