@Test(expected = IllegalArgumentException.class)
public void stateExistsForUserThatDoesNotExistTest() {

    // Setup:
    RepositoryConnection conn = repo.getConnection();
    conn.add(VALUE_FACTORY.createIRI("http://mobi.com/states/0"), VALUE_FACTORY.createIRI(RDF.TYPE.stringValue()), VALUE_FACTORY.createIRI(State.TYPE));
    when(engineManager.retrieveUser(anyString())).thenReturn(Optional.empty());
    manager.stateExistsForUser(VALUE_FACTORY.createIRI("http://mobi.com/states/0"), "error");
}