[TestMethod] public void DistinctTest()
 {
     list = SystemEnumerable.Distinct(list).ToList();
     Assert.AreEqual(5, list.Count);
     Assert.AreEqual(1, list[0]);
     Assert.AreEqual(3, list[1]);
     Assert.AreEqual(2, list[2]);
     Assert.AreEqual(4, list[3]);
     Assert.AreEqual(6, list[4]);
 }
 [TestMethod] public void OrderByTest()
 {
     list = SystemEnumerable.OrderBy(list, x => x.ToString()).ToList();
     Assert.AreEqual(6, list.Count);
     Assert.AreEqual(1, list[0]);
     Assert.AreEqual(1, list[1]);
     Assert.AreEqual(2, list[2]);
     Assert.AreEqual(3, list[3]);
     Assert.AreEqual(4, list[4]);
     Assert.AreEqual(6, list[5]);
 }
 public void ConvertTest()
 {
     var l = SystemEnumerable.Convert(list, x => x.ToString()).ToList();
     Assert.AreEqual(6, list.Count);
     Assert.AreEqual("1", l[0]);
     Assert.AreEqual("3", l[1]);
     Assert.AreEqual("2", l[2]);
     Assert.AreEqual("4", l[3]);
     Assert.AreEqual("1", l[4]);
     Assert.AreEqual("6", l[5]);
 }
 [TestMethod] public void ConvertWithNullArgumentsTest()
 {
     Assert.AreEqual(0, SystemEnumerable.Convert <int, string>(list, null).Count());
     Assert.AreEqual(0, SystemEnumerable.Convert <int, string>(null, x => x.ToString()).Count());
     Assert.AreEqual(0, SystemEnumerable.Convert <int, string>(null, null).Count());
 }
 [TestMethod] public void DistinctWithNullArgumentsTest()
 {
     Assert.AreEqual(0, SystemEnumerable.Distinct((IEnumerable <int>)null).Count());
 }
 [TestMethod] public void OrderByWithNullArgumentsTest()
 {
     Assert.AreEqual(0, SystemEnumerable.OrderBy(list, null).Count());
     Assert.AreEqual(0, SystemEnumerable.OrderBy <int>(null, x => x.ToString()).Count());
     Assert.AreEqual(0, SystemEnumerable.OrderBy <int>(null, null).Count());
 }