@Test public void splitLookup() { // do the split int pivot = 4; int max = 5; List<Integer> l = List.range(1, max + 1); TreeMap<Integer, String> m2 = TreeMap.treeMap(Ord.intOrd, l.zip(l.map(i -> i.toString()))); P3<TreeMap<Integer, String>, Option<String>, TreeMap<Integer, String>> p3 = m2.splitLookup(pivot); // create expected output List<Integer> leftList = List.range(1, pivot); TreeMap<Integer, String> leftMap = TreeMap.treeMap(Ord.intOrd, leftList.zip(leftList.map(i -> i.toString()))); List<Integer> rightList = List.range(pivot + 1, max + 1); TreeMap<Integer, String> rightMap = TreeMap.treeMap(Ord.intOrd, rightList.zip(rightList.map(i -> i.toString()))); // debug info if (true) { Show<TreeMap<Integer, String>> st = Show.treeMapShow(Show.intShow, Show.stringShow); Show<P3<TreeMap<Integer, String>, Option<String>, TreeMap<Integer, String>>> sp3 = Show.p3Show(st, Show.optionShow(Show.stringShow), st); sp3.println(p3); } // do the assert Equal<TreeMap<Integer, String>> tme = Equal.treeMapEqual(Equal.intEqual, Equal.stringEqual); Equal<P3<TreeMap<Integer, String>, Option<String>, TreeMap<Integer, String>>> eq = Equal.p3Equal(tme, Equal.optionEqual(Equal.stringEqual), tme); assertTrue(eq.eq(p3, p(leftMap, some(Integer.toString(pivot)), rightMap))); }