### Question:
LabelContainer { synchronized public Integer getLabelID(String label) { addLabel(label); return labelMap.indexOf(label); } protected  LabelContainer(); synchronized static LabelContainer getInstance(); synchronized void addLabel(String label); synchronized Integer getLabelID(String label); synchronized String getLabel(Integer labelID); synchronized int getSize();  }### Answer:
@Test public void testGetLabelID() { String label = "R3"; LabelContainer instance = new LabelContainer(); instance.addLabel(label); Integer expectedValue = 2; Assert.assertEquals(expectedValue, instance.getLabelID("R3")); }