public void Unionwith_DifferentIntValues_CorrectInserting(int[] values, int[] valuesForUnion, int[] expected)
        {
            AddValues(values);

            _intSet.UnionWith(valuesForUnion);

            int i = 0;

            foreach (var element in _intSet)
            {
                Assert.AreEqual(expected[i++], element);
            }
        }
 public void UnionWith_NullOther_ArgumentNullException()
 => Assert.Catch <ArgumentNullException>(() => _filledIntSet.UnionWith(null));