public void CheckSetUnionWith() { q = new SetCollection <int>(); var testSet1 = new int[] { 1, 2, 3, 4, 5 }; q.AddRange(testSet1); q.UnionWith(new int[] { 4, 5, 6, 7, 8 }); var expected = new int[] { 1, 2, 3, 4, 5, 6, 7, 8 }; CollectionAssert.AreEqual(expected, q); }