ALinq.Tests.AsyncEnumerableSingleTests.SingleShouldReturnElement C# (CSharp) Méthode

        public async Task SingleShouldReturnElement()
        {
            var sequence = new[] {10}.ToAsync();
            Assert.AreEqual(10,await sequence.Single());

            var sequence2 = new int[] {}.ToAsync();
            try
            {
                await sequence2.Single();
                Assert.Fail("No exception thrown");
            }
            catch (InvalidOperationException)
            {
            }

            var sequence3 = new int[] {10,11 }.ToAsync();
            try
            {
                await sequence3.Single();
                Assert.Fail("No exception thrown");
            }
            catch (InvalidOperationException)
            {  
            }
        }