private void assertLoggedInUser(HiveConnection connection, String expectedUser)
      throws SQLException {
    Statement stmt = connection.createStatement();
    ResultSet resultSet = stmt.executeQuery("select logged_in_user()");
    assertTrue(resultSet.next());
    String loggedInUser = resultSet.getString(1);
    assertEquals(expectedUser, loggedInUser);
  }
This is a hack to make environment variables modifiable.
Ref: https://stackoverflow.com/questions/318239/how-do-i-set-environment-variables-from-java.
itests/hive-unit/src/test/java/org/apache/hive/service/auth/jwt/TestHttpJwtAuthentication.java