@Test
public void testDeleteUser() {

    engine.deleteUser(username);
    RepositoryConnection connection = repo.getConnection();
    RepositoryResult<Statement> statements = connection.getStatements(VALUE_FACTORY.createIRI(userId), null, null);
    assertFalse(statements.hasNext());
    statements = connection.getStatements(null, null, VALUE_FACTORY.createIRI(userId));
    assertFalse(statements.hasNext());
    connection.close();
}