* see calls in Google code that pass a null `dir` to a FilenameFilter.... So let's declare the
   * parameter as non-nullable (since passing null to a FilenameFilter is unsafe in general), but if
   * someone still manages to pass null, let's continue to have the method work.
   *
   * (PatternFilenameFilter is of course one of those classes that shouldn't be a publicly visible

    assertFailsToDecode(base64(), "Wf2!", "Unrecognized character: !");
    // This sentence just isn't base64() encoded.
    assertFailsToDecode(base64(), "let's not talk of love or chains!");
    // A 4n+1 length string is never legal base64().
    assertFailsToDecode(base64(), "12345", "Invalid input length 5");

                  CollectionFeature.RESTRICTS_ELEMENTS,
                  ListFeature.SUPPORTS_SET)
              .createTestSuite());
    }
    return suite;
  }

  // Test generators.  To let the GWT test suite generator access them, they need to be
  // public named classes with a public default constructor.

  public static final class LongsAsListGenerator extends TestLongListGenerator {
    @Override

      safeMax = -1;
      safeMin = Integer.MAX_VALUE;
    }
    this.safeMin = safeMin;
    this.safeMax = safeMax;

    // This is a bit of a hack but lets us do quicker per-character checks in
    // the fast path code. The safe min/max values are very unlikely to extend
    // into the range of surrogate characters, but if they do we must not test

    // computation is in progress; asMap shouldn't have changed
    assertEquals(1, map.size());
    assertFalse(map.containsKey(getKey));
    assertSame(refreshKey, map.get(refreshKey));

    // let computation complete
    letGetFinishSignal.countDown();
    getFinishedSignal.await();
    checkNothingLogged();

    // asMap view should have been updated
    assertEquals(2, cache.size());

  @GwtIncompatible // used only from suite
  private static ImmutableDoubleArray makeArray(Double[] values) {
    return ImmutableDoubleArray.copyOf(Arrays.asList(values));
  }

  // Test generators.  To let the GWT test suite generator access them, they need to be public named
  // classes with a public default constructor (not that we run these suites under GWT yet).

  @J2ktIncompatible
  @GwtIncompatible // used only from suite

  @J2ktIncompatible
  @GwtIncompatible // used only from suite
  private static ImmutableLongArray makeArray(Long[] values) {
    return ImmutableLongArray.copyOf(Arrays.asList(values));
  }

  // Test generators.  To let the GWT test suite generator access them, they need to be public named
  // classes with a public default constructor (not that we run these suites under GWT yet).

  @J2ktIncompatible
  @GwtIncompatible // used only from suite

        if (array[min] > array[index]) {
          min = index;
        }
      }
      if (min != from) {
        swap(array, min, from);
      }
      return;
    }

    // Let's play quickselect! We'll repeatedly partition the range [from, to] containing the
    // required element, as long as it has more than one element.
    while (to > from) {
      int partitionPoint = partition(array, from, to);

    Set<SomeEnum> units = Stream.<SomeEnum>empty().collect(Sets.toImmutableEnumSet());
    assertThat(units).isEmpty();
  }

  public void testToImmutableEnumSetReused() {
    // The method call lets us capture the accumulator as an A and invoke the callbacks manually
    genericTestToImmutableEnumSetReused(Sets.<SomeEnum>toImmutableEnumSet());
  }

   */
  @GwtIncompatible // TODO
  public static long sqrt(long x, RoundingMode mode) {
    checkNonNegative("x", x);
    if (fitsInInt(x)) {
      return IntMath.sqrt((int) x, mode);
    }
    /*
     * Let k be the true value of floor(sqrt(x)), so that
     *
     *            k * k <= x          <  (k + 1) * (k + 1)
     * (double) (k * k) <= (double) x <= (double) ((k + 1) * (k + 1))