Is there a reason the parameter name for ForwardingMap.remove(Object object) does not match the interface: Map.remove(Object key)?  In short: 'object' != 'key'
If yes, please kindly explain the history.
Else, can we rename to 'key' to match the interface?
cutsToTest.add(Cut.belowValue(i));
      cutsToTest.add(Cut.aboveValue(i));
    }
    cutsToTest.add(Cut.<Integer>aboveAll());
    cutsToTest.add(Cut.<Integer>belowAll());
    CUTS_TO_TEST = ImmutableList.copyOf(cutsToTest);
  }
  private void testRangesByLowerBounds(
      TreeRangeSet<Integer> rangeSet, Iterable<Range<Integer>> expectedRanges) {
    NavigableMap<Cut<Integer>, Range<Integer>> expectedRangesByLowerBound = Maps.newTreeMap();
    for (Range<Integer> range : expectedRanges) {
      expectedRangesByLowerBound.put(range.lowerBound, range);
    }
    NavigableMap<Cut<Integer>, Range<Integer>> rangesByLowerBound = rangeSet.rangesByLowerBound;
    testNavigationAgainstExpected(expectedRangesByLowerBound, rangesByLowerBound, CUTS_TO_TEST);
  }
  <K, V> void testNavigationAgainstExpected(
      NavigableMap<K, V> expected, NavigableMap<K, V> navigableMap, Iterable<K> keysToTest) {
    for (K key : keysToTest) {
      assertEquals(expected.lowerEntry(key), navigableMap.lowerEntry(key));
      assertEquals(expected.floorEntry(key), navigableMap.floorEntry(key));
      assertEquals(expected.ceilingEntry(key), navigableMap.ceilingEntry(key));
      assertEquals(expected.higherEntry(key), navigableMap.higherEntry(key));
      for (boolean inclusive : new boolean[] {false, true}) {
        assertThat(navigableMap.headMap(key, inclusive).entrySet())
            .containsExactlyElementsIn(expected.headMap(key, inclusive).entrySet())
            .inOrder();
        assertThat(navigableMap.tailMap(key, inclusive).entrySet())
            .containsExactlyElementsIn(expected.tailMap(key, inclusive).entrySet())
            .inOrder();