### Question:
ObjectSelector { public ObjectSelector<T> lt(double v) { ObjectSelector<T> result = new ObjectSelector<T>(); final int n = scores.size(); for (int i=0; i<n; i++) { if (scores.get(i) < v) { result.add(elements.get(i), scores.get(i)); } } return result; }  void add(T element, Double score); void add(List<T> elements, double [] scores); void add(FeatureList features, DenseVector scores); @SuppressWarnings("unchecked") void add(ObjectSelector<Feature> list); int size(); ObjectSelector<T> selectLevelledSmallestScores(int n, int maxSize); DenseVector toDenseVector(); ObjectSelector<T> lt(double v); ObjectSelector<T> le(double v); ObjectSelector<T> gt(double v); ObjectSelector<T> ge(double v); ArrayList<T> getElements(); ArrayList<Double> getScores(); T getElement(int i); double getScore(int i);  }### Answer:
@Test public void testLt() { ObjectSelector<Integer> selector = new ObjectSelector<Integer>(); selector.add(1, 10.0); selector.add(2, 20.0); ObjectSelector<Integer> result = selector.lt(20.0); assertEquals(2, selector.size()); assertEquals(1, result.size()); assertEquals(1, (int) result.getElement(0)); assertEquals(10.0d, result.getScore(0), 0d); }