public static String getPassword(String user) {
    String password = USER_DATABASE.get(user);
    if (password == null) {
      throw new IllegalStateException("Cannot request password for a user that doesn't exist");
    }
    return password;
  }
Tests the pluggable authentication framework with SASL using a contrived authentication system.
This tests holds a "user database" in memory as a hashmap. Clients provide their password in the
client Hadoop configuration. The servers validate this password via the "user database".
hbase-server/src/test/java/org/apache/hadoop/hbase/security/provider/CustomSaslAuthenticationProviderTestBase.java