assertThrows(IllegalArgumentException.class, () -> LongMath.gcd(3, a));
    }
  }

  @GwtIncompatible // TODO
  public void testGCDNegativeZeroThrows() {
    for (long a : NEGATIVE_LONG_CANDIDATES) {
      assertThrows(IllegalArgumentException.class, () -> LongMath.gcd(a, 0));
      assertThrows(IllegalArgumentException.class, () -> LongMath.gcd(0, a));
    }