Throw on transfer options facade overflow

sdk/storage/Azure.Storage.Common/src/StorageTransferOptions.cs

@@ -19,7 +19,7 @@ public struct StorageTransferOptions : IEquatable<StorageTransferOptions>
         [EditorBrowsable(EditorBrowsableState.Never)]
         public int? MaximumTransferLength
         {
-            get => (int?)MaximumTransferSize;
+            get => checked((int?)MaximumTransferSize);
             set => MaximumTransferSize = value;
         }
 
@@ -43,7 +43,7 @@ public int? MaximumTransferLength
         [EditorBrowsable(EditorBrowsableState.Never)]
         public int? InitialTransferLength
         {
-            get => (int?)InitialTransferSize;
+            get => checked((int?)InitialTransferSize);
             set => InitialTransferSize = value;
         }
 

sdk/storage/Azure.Storage.Common/tests/StorageTransferOptionsTests.cs

@@ -0,0 +1,89 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using NUnit.Framework;
+
+namespace Azure.Storage.Tests
+{
+    public class StorageTransferOptionsTests
+    {
+        /// <summary>
+        /// Tests non-throwing cases for backwards compatibility of int? facade
+        /// <see cref="StorageTransferOptions.MaximumTransferLength"/>.
+        /// </summary>
+        /// <param name="realSize"></param>
+        [TestCase(default)]
+        [TestCase(1)]
+        [TestCase(int.MaxValue)]
+        public void MaxTransferLengthBackCompatTest(long? realSize)
+        {
+            var options = new StorageTransferOptions
+            {
+                MaximumTransferSize = realSize
+            };
+
+            Assert.AreEqual(options.MaximumTransferSize, realSize);
+            Assert.AreEqual(options.MaximumTransferLength, realSize);
+        }
+
+        /// <summary>
+        /// Tests throwing cases for backwards compatibility of int? facade
+        /// <see cref="StorageTransferOptions.MaximumTransferLength"/>.
+        /// </summary>
+        /// <param name="realSize"></param>
+        [TestCase(int.MaxValue + 1L)]
+        [TestCase(long.MaxValue)]
+        public void MaxTransferLengthBackCompatOverflowTest(long? realSize)
+        {
+            var options = new StorageTransferOptions
+            {
+                MaximumTransferSize = realSize
+            };
+
+            Assert.AreEqual(options.MaximumTransferSize, realSize);
+            Assert.Throws<OverflowException>(() => _ = options.MaximumTransferLength);
+        }
+
+        /// <summary>
+        /// Tests non-throwing cases for backwards compatibility of int? facade
+        /// <see cref="StorageTransferOptions.MaximumTransferLength"/>.
+        /// </summary>
+        /// <param name="realSize"></param>
+        [TestCase(default)]
+        [TestCase(1)]
+        [TestCase(int.MaxValue)]
+        public void InitialTransferLengthBackCompatTest(long? realSize)
+        {
+            var options = new StorageTransferOptions
+            {
+                InitialTransferSize = realSize
+            };
+
+            Assert.AreEqual(options.InitialTransferSize, realSize);
+            Assert.AreEqual(options.InitialTransferLength, realSize);
+        }
+
+        /// <summary>
+        /// Tests throwing cases for backwards compatibility of int? facade
+        /// <see cref="StorageTransferOptions.MaximumTransferLength"/>.
+        /// </summary>
+        /// <param name="realSize"></param>
+        [TestCase(int.MaxValue + 1L)]
+        [TestCase(long.MaxValue)]
+        public void InitialTransferLengthBackCompatOverflowTest(long? realSize)
+        {
+            var options = new StorageTransferOptions
+            {
+                InitialTransferSize = realSize
+            };
+
+            Assert.AreEqual(options.InitialTransferSize, realSize);
+            Assert.Throws<OverflowException>(() => _ = options.InitialTransferLength);
+        }
+    }
+}