### Question:
OAuthUtil { static String createSigningKey(String consumerSecret, String tokenSecret) { StringBuilder signingKey = new StringBuilder(); signingKey.append(urlEncode(consumerSecret)); signingKey.append('&'); if (tokenSecret != null) { signingKey.append(tokenSecret); } return signingKey.toString(); } OAuthUtil(OAuthParams params); HttpRequest2 createSignedRequest(HttpRequest2 httpRequest); String createAuthorization(HttpMethod method, String url, List<? extends Entry<String, String>> params); static final String AUTHORIZATION_HEADER_KEY; }### Answer:
@Test public void testCreateSigningKey() { String signingKey = OAuthUtil.createSigningKey(CONSUMER_SECRET, TOKEN_SECRET); assertEquals(EXPECTED_SIGNING_KEY, signingKey); }