### Question:
Start extends NodeBase { @Override public void removeParent(NodeBase parent) { throw new IllegalStateException("Start nodes cannot have parents."); } Start(final String name); NodeBase getChild(); @Override void addParent(final NodeBase parent); @Override void addParentWithCondition(final Decision parent, final Condition condition); @Override void addParentDefaultConditional(Decision parent); @Override void removeParent(NodeBase parent); @Override void clearParents(); @Override List<NodeBase> getChildren();  }### Answer:
@Test public void testRemoveParent() { final Start start = getInstance("start"); expectedException.expect(IllegalStateException.class); start.removeParent(null); }