### Question:
SecondaryProblemFactory { public List<SecondaryProblem> listObjectives() { return listObjectives(null); } SecondaryProblemFactory(); static synchronized SecondaryProblemFactory getInstance(); SecondaryProblem createSecondaryObjective(String name); String listSecondaryObjectivesAsString(); List<SecondaryProblem> listObjectives(); List<SecondaryProblem> listObjectives(Objective.ObjectiveType objectiveType); List<String> listObjectivesByIdentifier(); List<String> listObjectivesByIdentifier(Objective.ObjectiveType objectiveType);  }### Answer:
@Test public void testListObjectives() { List<String> objectives = SecondaryProblemFactory.getInstance().listObjectivesByIdentifier(); assertTrue(objectives.contains("BALANCED")); }