Add tests for ToEnumerable.

Ix.NET/Source/System.Linq.Async.Tests/System/Linq/Operators/ToEnumerable.cs

@@ -3,7 +3,9 @@
 // See the LICENSE file in the project root for more information. 
 
 using System;
+using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using Xunit;
 
 namespace Tests
@@ -17,25 +19,57 @@ namespace Tests
         }
 
         [Fact]
-        public void ToEnumerable1()
+        public void ToEnumerable_Single()
         {
             var xs = Return42.ToEnumerable();
             Assert.True(xs.SequenceEqual(new[] { 42 }));
         }
 
         [Fact]
-        public void ToEnumerable2()
+        public void ToEnumerable_Empty()
         {
             var xs = AsyncEnumerable.Empty<int>().ToEnumerable();
             Assert.True(xs.SequenceEqual(new int[0]));
         }
 
         [Fact]
-        public void ToEnumerable3()
+        public void ToEnumerable_Throws_Source()
         {
             var ex = new Exception("Bang");
             var xs = Throw<int>(ex).ToEnumerable();
             Assert.Throws<Exception>(() => xs.GetEnumerator().MoveNext());
         }
+
+        [Fact]
+        public void ToEnumerable_Many()
+        {
+            var xs = new[] { 1, 2, 3 };
+
+            Assert.Equal(xs, xs.ToAsyncEnumerable().ToEnumerable());
+        }
+
+        [Fact]
+        public void ToEnumerable_Many_Yield()
+        {
+            var xs = new[] { 1, 2, 3 };
+
+            Assert.Equal(xs, Yielded(xs).ToEnumerable());
+        }
+
+        private static async IAsyncEnumerable<int> Yielded(IEnumerable<int> xs)
+        {
+            try
+            {
+                foreach (var x in xs)
+                {
+                    await Task.Yield();
+                    yield return x;
+                }
+            }
+            finally
+            {
+                await Task.Yield();
+            }
+        }
     }
 }