SingleAsync code coverage.

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

@@ -13,107 +13,218 @@ namespace Tests
     public class Single : AsyncEnumerableTests
     {
         [Fact]
-        public async Task Single_Null()
+        public async Task SingleAsync_Null()
         {
             await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default).AsTask());
-
             await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, CancellationToken.None).AsTask());
+        }
 
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, x => true).AsTask());
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, bool>)).AsTask());
+        [Fact]
+        public async Task SingleAsync_Empty()
+        {
+            var res = AsyncEnumerable.Empty<int>().SingleAsync();
+            await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
+        }
 
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, x => true, CancellationToken.None).AsTask());
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, bool>), CancellationToken.None).AsTask());
+        [Fact]
+        public async Task SingleAsync_Empty_IList()
+        {
+            var res = new int[0].ToAsyncEnumerable().SingleAsync();
+            await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
+        }
 
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, x => new ValueTask<bool>(true)).AsTask());
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, ValueTask<bool>>)).AsTask());
+        [Fact]
+        public async Task SingleAsync_Single()
+        {
+            var res = Return42.SingleAsync();
+            Assert.Equal(42, await res);
+        }
 
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, x => new ValueTask<bool>(true), CancellationToken.None).AsTask());
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, ValueTask<bool>>), CancellationToken.None).AsTask());
+        [Fact]
+        public async Task SingleAsync_Simple()
+        {
+            var res = new[] { 1, 2, 3, 4, 5 }.ToAsyncEnumerable().Where(x => x == 4).SingleAsync();
+            Assert.Equal(4, await res);
+        }
 
-#if !NO_DEEP_CANCELLATION
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, (x, ct) => new ValueTask<bool>(true), CancellationToken.None).AsTask());
-            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, CancellationToken, ValueTask<bool>>), CancellationToken.None).AsTask());
-#endif
+        [Fact]
+        public async Task SingleAsync_Throws_Source()
+        {
+            var ex = new Exception("Bang!");
+            var res = Throw<int>(ex).SingleAsync();
+            await AssertThrowsAsync(res, ex);
         }
 
         [Fact]
-        public async Task Single1Async()
+        public async Task SingleAsync_Throw_MoreThanOne_IList()
         {
-            var res = AsyncEnumerable.Empty<int>().SingleAsync();
+            var res = new[] { 42, 45, 90 }.ToAsyncEnumerable().SingleAsync();
             await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
         }
 
         [Fact]
-        public async Task Single2Async()
+        public async Task SingleAsync_Throw_MoreThanOne()
         {
-            var res = AsyncEnumerable.Empty<int>().SingleAsync(x => true);
+            var res = new[] { 42, 45, 90 }.ToAsyncEnumerable().Select(x => x).SingleAsync();
             await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
         }
 
         [Fact]
-        public async Task Single3Async()
+        public async Task SingleAsync_Predicate_Null()
         {
-            var res = Return42.SingleAsync(x => x % 2 != 0);
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, x => true).AsTask());
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, bool>)).AsTask());
+
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, x => true, CancellationToken.None).AsTask());
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, bool>), CancellationToken.None).AsTask());
+        }
+
+        [Fact]
+        public async Task SingleAsync_Predicate_Empty()
+        {
+            var res = AsyncEnumerable.Empty<int>().SingleAsync(x => true);
             await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
         }
 
         [Fact]
-        public async Task Single4Async()
+        public async Task SingleAsync_Predicate_NoMatch()
         {
-            var res = Return42.SingleAsync();
-            Assert.Equal(42, await res);
+            var res = Return42.SingleAsync(x => x % 2 != 0);
+            await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
         }
 
         [Fact]
-        public async Task Single5Async()
+        public async Task SingleAsync_Predicate_Simple()
         {
             var res = Return42.SingleAsync(x => x % 2 == 0);
             Assert.Equal(42, await res);
         }
 
         [Fact]
-        public async Task Single6Async()
+        public async Task SingleAsync_Predicate_Throws()
         {
             var ex = new Exception("Bang!");
-            var res = Throw<int>(ex).SingleAsync();
+            var res = Throw<int>(ex).SingleAsync(x => true);
             await AssertThrowsAsync(res, ex);
         }
 
         [Fact]
-        public async Task Single7Async()
+        public async Task SingleAsync_Predicate_OneMatch()
+        {
+            var res = new[] { 42, 45, 90 }.ToAsyncEnumerable().SingleAsync(x => x % 2 != 0);
+            Assert.Equal(45, await res);
+        }
+
+        [Fact]
+        public async Task SingleAsync_Predicate_Throw_MoreThanOne()
+        {
+            var res = new[] { 42, 23, 45, 90 }.ToAsyncEnumerable().SingleAsync(x => x % 2 != 0);
+            await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Null()
+        {
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, x => new ValueTask<bool>(true)).AsTask());
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, ValueTask<bool>>)).AsTask());
+
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, x => new ValueTask<bool>(true), CancellationToken.None).AsTask());
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, ValueTask<bool>>), CancellationToken.None).AsTask());
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Empty()
+        {
+            var res = AsyncEnumerable.Empty<int>().SingleAsync(x => new ValueTask<bool>(true));
+            await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_NoMatch()
+        {
+            var res = Return42.SingleAsync(x => new ValueTask<bool>(x % 2 != 0));
+            await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Simple()
+        {
+            var res = Return42.SingleAsync(x => new ValueTask<bool>(x % 2 == 0));
+            Assert.Equal(42, await res);
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Throws()
         {
             var ex = new Exception("Bang!");
-            var res = Throw<int>(ex).SingleAsync(x => true);
+            var res = Throw<int>(ex).SingleAsync(x => new ValueTask<bool>(true));
             await AssertThrowsAsync(res, ex);
         }
 
         [Fact]
-        public async Task Single8Async()
+        public async Task SingleAsync_AsyncPredicate_OneMatch()
         {
-            var res = new[] { 42, 45, 90 }.ToAsyncEnumerable().SingleAsync();
+            var res = new[] { 42, 45, 90 }.ToAsyncEnumerable().SingleAsync(x => new ValueTask<bool>(x % 2 != 0));
+            Assert.Equal(45, await res);
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Throw_MoreThanOne()
+        {
+            var res = new[] { 42, 23, 45, 90 }.ToAsyncEnumerable().SingleAsync(x => new ValueTask<bool>(x % 2 != 0));
             await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
         }
 
+#if !NO_DEEP_CANCELLATION
         [Fact]
-        public async Task Single9Async()
+        public async Task SingleAsync_AsyncPredicate_Cancel_Null()
         {
-            var res = new[] { 42, 45, 90 }.ToAsyncEnumerable().SingleAsync(x => x % 2 != 0);
-            Assert.Equal(45, await res);
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync<int>(default, (x, ct) => new ValueTask<bool>(true), CancellationToken.None).AsTask());
+            await Assert.ThrowsAsync<ArgumentNullException>(() => AsyncEnumerable.SingleAsync(Return42, default(Func<int, CancellationToken, ValueTask<bool>>), CancellationToken.None).AsTask());
         }
 
         [Fact]
-        public async Task Single10Async()
+        public async Task SingleAsync_AsyncPredicate_Cancel_Empty()
         {
-            var res = new[] { 42, 23, 45, 90 }.ToAsyncEnumerable().SingleAsync(x => x % 2 != 0);
+            var res = AsyncEnumerable.Empty<int>().SingleAsync((x, ct) => new ValueTask<bool>(true));
             await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
         }
 
         [Fact]
-        public async Task Single11Async()
+        public async Task SingleAsync_AsyncPredicate_Cancel_NoMatch()
         {
-            var res = new int[0].ToAsyncEnumerable().SingleAsync();
+            var res = Return42.SingleAsync((x, ct) => new ValueTask<bool>(x % 2 != 0));
+            await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Cancel_Simple()
+        {
+            var res = Return42.SingleAsync((x, ct) => new ValueTask<bool>(x % 2 == 0));
+            Assert.Equal(42, await res);
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Cancel_Throws()
+        {
+            var ex = new Exception("Bang!");
+            var res = Throw<int>(ex).SingleAsync((x, ct) => new ValueTask<bool>(true));
+            await AssertThrowsAsync(res, ex);
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Cancel_OneMatch()
+        {
+            var res = new[] { 42, 45, 90 }.ToAsyncEnumerable().SingleAsync((x, ct) => new ValueTask<bool>(x % 2 != 0));
+            Assert.Equal(45, await res);
+        }
+
+        [Fact]
+        public async Task SingleAsync_AsyncPredicate_Cancel_Throw_MoreThanOne()
+        {
+            var res = new[] { 42, 23, 45, 90 }.ToAsyncEnumerable().SingleAsync((x, ct) => new ValueTask<bool>(x % 2 != 0));
             await AssertThrowsAsync<InvalidOperationException>(res.AsTask());
         }
+#endif
     }
 }