Use Assert.ThrowsAsync directly and ensure result is awaited

Ix.NET/Source/Tests/AsyncTests.Multiple.cs

@@ -9,6 +9,7 @@ using System.Linq;
 using System.Text;
 using Xunit;
 using System.Threading;
+using System.Threading.Tasks;
 
 namespace Tests
 {
@@ -324,21 +325,21 @@ namespace Tests
         }
 
         [Fact]
-        public void SequenceEqual_Null()
+        public async Task SequenceEqual_Null()
         {
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(null, AsyncEnumerable.Return(42)));
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), null));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(null, AsyncEnumerable.Return(42)));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), null));
 
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(null, AsyncEnumerable.Return(42), new Eq()));
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), null, new Eq()));
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), AsyncEnumerable.Return(42), null));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(null, AsyncEnumerable.Return(42), new Eq()));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), null, new Eq()));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), AsyncEnumerable.Return(42), null));
 
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(null, AsyncEnumerable.Return(42), CancellationToken.None));
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), null, CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(null, AsyncEnumerable.Return(42), CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), null, CancellationToken.None));
 
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(null, AsyncEnumerable.Return(42), new Eq(), CancellationToken.None));
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), null, new Eq(), CancellationToken.None));
-            AssertThrows<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), AsyncEnumerable.Return(42), null, CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(null, AsyncEnumerable.Return(42), new Eq(), CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), null, new Eq(), CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SequenceEqual<int>(AsyncEnumerable.Return(42), AsyncEnumerable.Return(42), null, CancellationToken.None));
         }
 
         [Fact]

Ix.NET/Source/Tests/AsyncTests.Single.cs

@@ -571,15 +571,15 @@ namespace Tests
         [Fact]
         public async Task ForEachAsync_Null()
         {
-            await AssertThrows<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(null, x => { }));
-            await AssertThrows<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(AsyncEnumerable.Return(42), default(Action<int>)));
-            await AssertThrows<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(null, (x, i) => { }));
-            await AssertThrows<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(AsyncEnumerable.Return(42), default(Action<int, int>)));
-
-            await AssertThrows<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(null, x => { }, CancellationToken.None));
-            await AssertThrows<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(AsyncEnumerable.Return(42), default(Action<int>), CancellationToken.None));
-            await AssertThrows<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(null, (x, i) => { }, CancellationToken.None));
-            await AssertThrows<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(AsyncEnumerable.Return(42), default(Action<int, int>), CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(null, x => { }));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(AsyncEnumerable.Return(42), default(Action<int>)));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(null, (x, i) => { }));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(AsyncEnumerable.Return(42), default(Action<int, int>)));
+
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(null, x => { }, CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(AsyncEnumerable.Return(42), default(Action<int>), CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(null, (x, i) => { }, CancellationToken.None));
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.ForEachAsync<int>(AsyncEnumerable.Return(42), default(Action<int, int>), CancellationToken.None));
         }
 
         [Fact]

Ix.NET/Source/Tests/AsyncTests.cs

@@ -20,6 +20,7 @@ namespace Tests
             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
         {