Adding base class for tests.

Ix.NET/Source/System.Interactive.Async.Tests/System/Linq/AsyncEnumerableExTests.cs

@@ -0,0 +1,88 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the Apache 2.0 License.
+// 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 FluentAssertions;
+using Xunit;
+
+namespace Tests
+{
+    public class AsyncEnumerableExTests
+    {
+        protected const int WaitTimeoutMs = 5000;
+
+#pragma warning disable xUnit1013 // Public method should be marked as test
+        public void AssertThrows<E>(Action a)
+            where E : Exception
+        {
+            Assert.Throws<E>(a);
+        }
+
+        [Obsolete("Don't use this, use Assert.ThrowsAsync and await it", true)]
+        public Task AssertThrows<E>(Func<Task> func)
+            where E : Exception
+        {
+            return Assert.ThrowsAsync<E>(func);
+        }
+
+        public void AssertThrows<E>(Action a, Func<E, bool> assert)
+            where E : Exception
+        {
+
+            var hasFailed = false;
+
+            try
+            {
+                a();
+            }
+            catch (E e)
+            {
+                Assert.True(assert(e));
+                hasFailed = true;
+            }
+
+            if (!hasFailed)
+            {
+                Assert.True(false);
+            }
+        }
+
+        public void NoNext<T>(IAsyncEnumerator<T> e)
+        {
+            Assert.False(e.MoveNextAsync().Result);
+        }
+
+        public void HasNext<T>(IAsyncEnumerator<T> e, T value)
+        {
+            Assert.True(e.MoveNextAsync().Result);
+            Assert.Equal(value, e.Current);
+        }
+
+        public async Task SequenceIdentity<T>(IAsyncEnumerable<T> enumerable)
+        {
+            var en1 = enumerable.GetAsyncEnumerator();
+            var en2 = enumerable.GetAsyncEnumerator();
+
+            Assert.Equal(en1.GetType(), en2.GetType());
+
+            await en1.DisposeAsync();
+            await en2.DisposeAsync();
+
+            var e1t = enumerable.ToList();
+            var e2t = enumerable.ToList();
+
+            await Task.WhenAll(e1t, e2t);
+
+
+            var e1Result = e1t.Result;
+            var e2Result = e2t.Result;
+
+            e1Result.ShouldAllBeEquivalentTo(e2Result);
+        }
+#pragma warning restore xUnit1013 // Public method should be marked as test
+    }
+}