System.Net.WebHeaderCollectionTests.WebHeaderCollectionTest.Enumerator_Success C# (CSharp) Method

        public void Enumerator_Success()
        {
            string item1 = "Accept";
            string item2 = "Content-Length";
            string item3 = "Name";

            WebHeaderCollection w = new WebHeaderCollection();
            w[item1] = "text/plain";
            w[item2] = "123";
            w[item3] = "value";

            IEnumerable collection = w;
            IEnumerator e = collection.GetEnumerator();

            for (int i = 0; i < 2; i++)
            {
                // Not started
                Assert.Throws<InvalidOperationException>(() => e.Current);

                Assert.True(e.MoveNext());
                Assert.Same(item1, e.Current);

                Assert.True(e.MoveNext());
                Assert.Same(item2, e.Current);

                Assert.True(e.MoveNext());
                Assert.Same(item3, e.Current);

                Assert.False(e.MoveNext());
                Assert.False(e.MoveNext());
                Assert.False(e.MoveNext());

                // Ended
                Assert.Throws<InvalidOperationException>(() => e.Current);

                e.Reset();
            }
        }
    }