Cleaning up some test code.

Ix.NET/Source/System.Interactive.Async.Tests/System/Linq/Operators/MaxBy.cs

@@ -52,7 +52,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 3, 5, 7, 6, 4, 2 }.ToAsyncEnumerable().MaxBy(x => { if (x == 3) throw ex; return x; });
 
-            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -61,7 +61,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 3, 5, 7, 6, 4, 2 }.ToAsyncEnumerable().MaxBy(x => { if (x == 4) throw ex; return x; });
 
-            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -70,7 +70,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 3, 5, 7, 6, 4, 2 }.ToAsyncEnumerable().Concat(Throw<int>(ex)).MaxBy(x => x, Comparer<int>.Default);
 
-            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

Ix.NET/Source/System.Interactive.Async.Tests/System/Linq/Operators/MinBy.cs

@@ -52,7 +52,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 3, 5, 7, 6, 4, 2 }.ToAsyncEnumerable().MinBy(x => { if (x == 3) throw ex; return x; });
 
-            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -61,7 +61,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 3, 5, 7, 6, 4, 2 }.ToAsyncEnumerable().MinBy(x => { if (x == 4) throw ex; return x; });
 
-            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -70,7 +70,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 3, 5, 7, 6, 4, 2 }.ToAsyncEnumerable().Concat(Throw<int>(ex)).MinBy(x => x, Comparer<int>.Default);
 
-            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

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

@@ -59,7 +59,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = Throw<int>(ex);
             var ys = xs.Aggregate((x, y) => x * y);
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -68,7 +68,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 1, 2, 3, 4 }.ToAsyncEnumerable();
             var ys = xs.Aggregate(new Func<int, int, int>((x, y) => { throw ex; }));
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -93,7 +93,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = Throw<int>(ex);
             var ys = xs.Aggregate(1, (x, y) => x * y);
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -102,7 +102,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 1, 2, 3, 4 }.ToAsyncEnumerable();
             var ys = xs.Aggregate(1, new Func<int, int, int>((x, y) => { throw ex; }));
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -127,7 +127,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = Throw<int>(ex);
             var ys = xs.Aggregate(1, (x, y) => x * y, x => x + 1);
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -136,7 +136,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 1, 2, 3, 4 }.ToAsyncEnumerable();
             var ys = xs.Aggregate(1, (x, y) => { throw ex; }, x => x + 1);
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -145,7 +145,7 @@ namespace Tests
             var ex = new Exception("Bang!");
             var xs = new[] { 1, 2, 3, 4 }.ToAsyncEnumerable();
             var ys = xs.Aggregate<int, int, int>(1, (x, y) => x * y, x => { throw ex; });
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

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

@@ -42,7 +42,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).All(x => x % 2 == 0);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -50,7 +50,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = new[] { 2, 8, 4 }.ToAsyncEnumerable().All(new Func<int, bool>(x => { throw ex; }));
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

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

@@ -44,7 +44,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).Any(x => x % 2 == 0);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -52,7 +52,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = new[] { 2, 8, 4 }.ToAsyncEnumerable().Any(new Func<int, bool>(x => { throw ex; }));
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -46,7 +46,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var ys = new[] { 1, 2, 3 }.ToAsyncEnumerable().Count(new Func<int, bool>(x => { throw ex; }));
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

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

@@ -63,7 +63,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).ElementAt(15);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

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

@@ -67,7 +67,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).ElementAtOrDefault(15);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

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

@@ -65,7 +65,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).First();
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -73,7 +73,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).First(x => true);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -65,7 +65,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).FirstOrDefault();
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -73,7 +73,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).FirstOrDefault(x => true);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -53,7 +53,7 @@ namespace Tests
             var ex = new Exception("Bang");
             var xs = new[] { 1, 2, 3, 4 }.ToAsyncEnumerable();
 
-            AssertThrows<Exception>(() => xs.ForEachAsync(x => { throw ex; }).Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.ForEachAsync(x => { throw ex; }).Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -62,7 +62,7 @@ namespace Tests
             var ex = new Exception("Bang");
             var xs = new[] { 1, 2, 3, 4 }.ToAsyncEnumerable();
 
-            AssertThrows<Exception>(() => xs.ForEachAsync((x, i) => { throw ex; }).Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.ForEachAsync((x, i) => { throw ex; }).Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -71,7 +71,7 @@ namespace Tests
             var ex = new Exception("Bang");
             var xs = Throw<int>(ex);
 
-            AssertThrows<Exception>(() => xs.ForEachAsync(x => { throw ex; }).Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.ForEachAsync(x => { throw ex; }).Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -80,7 +80,7 @@ namespace Tests
             var ex = new Exception("Bang");
             var xs = Throw<int>(ex);
 
-            AssertThrows<Exception>(() => xs.ForEachAsync((x, i) => { throw ex; }).Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => xs.ForEachAsync((x, i) => { throw ex; }).Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

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

@@ -264,8 +264,8 @@ namespace Tests
             //HasNext(g2e, 2);
 
 
-            //AssertThrows<Exception>(() => g1e.MoveNext().Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
-            //AssertThrows<Exception>(() => g2e.MoveNext().Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            //AssertThrows<Exception>(() => g1e.MoveNext().Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
+            //AssertThrows<Exception>(() => g2e.MoveNext().Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -65,7 +65,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).Last();
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -73,7 +73,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).Last(x => true);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -65,7 +65,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).LastOrDefault();
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -73,7 +73,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).LastOrDefault(x => true);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -46,7 +46,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var ys = new[] { 1, 2, 3 }.ToAsyncEnumerable().LongCount(new Func<int, bool>(x => { throw ex; }));
-            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => ys.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }

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

@@ -80,7 +80,7 @@ namespace Tests
             var ys = Throw<int>(ex);
             var res = xs.SequenceEqual(ys);
 
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -91,7 +91,7 @@ namespace Tests
             var ys = new[] { 1, 2, 3, 4 }.ToAsyncEnumerable();
             var res = xs.SequenceEqual(ys);
 
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -145,7 +145,7 @@ namespace Tests
             var ys = Throw<int>(ex);
             var res = xs.SequenceEqual(ys, new Eq());
 
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -156,7 +156,7 @@ namespace Tests
             var ys = new[] { 1, 2, 3, 4 }.ToAsyncEnumerable();
             var res = xs.SequenceEqual(ys, new Eq());
 
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -65,7 +65,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).Single();
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -73,7 +73,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).Single(x => true);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -65,7 +65,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).SingleOrDefault();
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]
@@ -73,7 +73,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).SingleOrDefault(x => true);
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -41,7 +41,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).ToArray();
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
 
         [Fact]

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

@@ -41,7 +41,7 @@ namespace Tests
         {
             var ex = new Exception("Bang!");
             var res = Throw<int>(ex).ToList();
-            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), ex_ => ((AggregateException)ex_).Flatten().InnerExceptions.Single() == ex);
+            AssertThrows<Exception>(() => res.Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex));
         }
     }
 }