/**
   * Tests regular NavigableMap behavior of synchronizedNavigableMap(treeMap); does not test the
   * fact that it's synchronized.
   */
  public Test testsForSynchronizedNavigableMap() {
    return NavigableMapTestSuiteBuilder.using(
            new TestStringSortedMapGenerator() {
              @Override
              protected SortedMap<String, String> create(Entry<String, String>[] entries) {

            CollectionSize.ANY)
        .suppressing(suppressForLinkedHashMap())
        .createTestSuite();
  }

  public Test testsForTreeMapNatural() {
    return NavigableMapTestSuiteBuilder.using(
            new TestStringSortedMapGenerator() {
              @Override
              protected SortedMap<String, String> create(Entry<String, String>[] entries) {
                /*

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.collect.testing.DerivedComparable;
import com.google.common.collect.testing.NavigableMapTestSuiteBuilder;
import com.google.common.collect.testing.NavigableSetTestSuiteBuilder;
import com.google.common.collect.testing.SampleElements;
import com.google.common.collect.testing.TestSortedMapGenerator;

import com.google.common.collect.ImmutableSortedMap.Builder;
import com.google.common.collect.testing.ListTestSuiteBuilder;
import com.google.common.collect.testing.MapTestSuiteBuilder;
import com.google.common.collect.testing.NavigableMapTestSuiteBuilder;
import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.MapFeature;

      return createSubMap(map, firstExclusive, lastExclusive);
    }

    /**
     * Calls the smallest subMap overload that filters out the extreme values. This method is
     * overridden in NavigableMapTestSuiteBuilder.
     */
    SortedMap<K, V> createSubMap(SortedMap<K, V> map, K firstExclusive, K lastExclusive) {
      if (from == Bound.NO_BOUND && to == Bound.EXCLUSIVE) {
        return map.headMap(lastExclusive);