assertPermutationsCount(1, Collections2.permutations(Collections.<Integer>emptyList()));
    assertPermutationsCount(1, Collections2.permutations(newArrayList(1)));
    assertPermutationsCount(2, Collections2.permutations(newArrayList(1, 2)));
    assertPermutationsCount(6, Collections2.permutations(newArrayList(1, 2, 3)));
    assertPermutationsCount(5040, Collections2.permutations(newArrayList(1, 2, 3, 4, 5, 6, 7)));

    assertPermutationsCount(1, Collections2.permutations(Collections.<Integer>emptyList()));
    assertPermutationsCount(1, Collections2.permutations(newArrayList(1)));
    assertPermutationsCount(2, Collections2.permutations(newArrayList(1, 2)));
    assertPermutationsCount(6, Collections2.permutations(newArrayList(1, 2, 3)));
    assertPermutationsCount(5040, Collections2.permutations(newArrayList(1, 2, 3, 4, 5, 6, 7)));

    }
  }

  public void testRemoveAt_exhaustive() {
    int size = reduceExponentIfGwt(8);
    List<Integer> expected = createOrderedList(size);
    for (Collection<Integer> perm : Collections2.permutations(expected)) {
      for (int i = 0; i < perm.size(); i++) {
        MinMaxPriorityQueue<Integer> q = MinMaxPriorityQueue.create(perm);
        q.removeAtForTesting(i);

    }
  }

  public void testRemoveAt_exhaustive() {
    int size = reduceExponentIfGwt(8);
    List<Integer> expected = createOrderedList(size);
    for (Collection<Integer> perm : Collections2.permutations(expected)) {
      for (int i = 0; i < perm.size(); i++) {
        MinMaxPriorityQueue<Integer> q = MinMaxPriorityQueue.create(perm);
        q.removeAtForTesting(i);

      Map<K, ? extends V> map) {
    if (map instanceof SortedMap) {
      return Collections.unmodifiableSortedMap((SortedMap<K, ? extends V>) map);
    } else {
      return Collections.unmodifiableMap(map);
    }
  }

  private static class MapDifferenceImpl<K extends @Nullable Object, V extends @Nullable Object>

      Map<K, ? extends V> map) {
    if (map instanceof SortedMap) {
      return Collections.unmodifiableSortedMap((SortedMap<K, ? extends V>) map);
    } else {
      return Collections.unmodifiableMap(map);
    }
  }

  private static class MapDifferenceImpl<K extends @Nullable Object, V extends @Nullable Object>

        assertEquals("aaa\\/bbb", getQuery("aaa/bbb", new String[0], Collections.emptyMap(), Collections.emptyMap(), true));
        assertEquals("\\\\", getQuery("\\", new String[0], Collections.emptyMap(), Collections.emptyMap(), true));
        assertEquals("\\\\\\\\", getQuery("\\\\", new String[0], Collections.emptyMap(), Collections.emptyMap(), true));

        final String json = new JsonIndexExportFormatter().format(source, Collections.emptySet());

        assertFalse(json.contains("field_with_null"));
    }

    @Test
    public void test_jsonFormatter_emptyMap() {
        final String json = new JsonIndexExportFormatter().format(Collections.emptyMap(), Collections.emptySet());

        assertTrue(json.contains("{"));

  }

  // Creation tests

  public void testEmptyBuilder() {
    ImmutableBiMap<String, Integer> map = new Builder<String, Integer>().build();
    assertEquals(Collections.<String, Integer>emptyMap(), map);
    assertEquals(Collections.<Integer, String>emptyMap(), map.inverse());
    assertThat(map).isSameInstanceAs(ImmutableBiMap.of());
  }

  public void testSingletonBuilder() {

            return "test query";
        }

        @Override
        public Map<String, String[]> getFields() {
            return Collections.emptyMap();
        }

        @Override
        public Map<String, String[]> getConditions() {
            return Collections.emptyMap();
        }

        @Override
        public String[] getLanguages() {
            return new String[0];
        }