System.Collections.Tests.IEnumerable_NonGeneric_Tests.CloneEnumerator_MatchesOriginal C# (CSharp) Method

        public void CloneEnumerator_MatchesOriginal(int count)
        {
            IEnumerator e1 = NonGenericIEnumerableFactory(count).GetEnumerator();

            ICloneable c1 = e1 as ICloneable;
            if (c1 == null)
            {
                // Only test if the enumerator can be cloned
                return;
            }

            // Walk the enumerator, and at each step of the way, clone it.
            // For all cloned enumerators, make sure they match the original
            // for the remainder of the iteration.
            var enumerators = new List<IEnumerator>();
            while (e1.MoveNext())
            {
                foreach (IEnumerator e2 in enumerators)
                {
                    Assert.True(e2.MoveNext(), "Could not MoveNext the enumerator");
                    Assert.Equal(e1.Current, e2.Current);
                }

                if (enumerators.Count < 10) // arbitrary limit to time-consuming N^2 behavior
                {
                    enumerators.Add((IEnumerator)c1.Clone());
                }
            }
            foreach (IEnumerator e2 in enumerators)
            {
                Assert.False(e2.MoveNext(), "Expected to not be able to MoveNext the enumerator");
            }
        }
    }