default void doTest(String json, String username, String password, Integer expectedFailureCode,
        ILdapComponent ldapComponentUnderTest)
         throws Exception {
        doTest(json, username, password, expectedFailureCode, null, ldapComponentUnderTest);
    }
Creates the http Authorization string for the given credentials.

@param username
@param password
gateway/engine/policies/src/test/java/io/apiman/gateway/engine/policies/util/LdapTestMixin.java