Add tests for invalid HashCore usage

Author: stephentoub

src/System.Security.Cryptography.Hashing.Algorithms/tests/InvalidUsageTests.cs

@@ -0,0 +1,80 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System.IO;
+using Xunit;
+
+namespace System.Security.Cryptography.Hashing.Algorithms.Tests
+{
+    public class InvalidUsageTests
+    {
+        [Fact]
+        public void InvalidHashCoreArgumentsFromDerivedType()
+        {
+            using (var hmac = new DerivedHMACSHA1())
+            {
+                Assert.Throws<ArgumentNullException>(() => hmac.ExposedHashCore(null, 0, 0));
+                Assert.Throws<ArgumentOutOfRangeException>(() => hmac.ExposedHashCore(new byte[1], -1, 1));
+                Assert.Throws<ArgumentOutOfRangeException>(() => hmac.ExposedHashCore(new byte[1], 0, -1));
+                Assert.Throws<ArgumentException>(() => hmac.ExposedHashCore(new byte[1], 0, 2));
+                Assert.Throws<ArgumentException>(() => hmac.ExposedHashCore(new byte[2], 1, 2));
+                Assert.Throws<ArgumentException>(() => hmac.ExposedHashCore(new byte[1], Int32.MaxValue, Int32.MaxValue));
+            }
+        }
+
+        [Fact]
+        public void InvalidHashCoreArgumentsFromStream()
+        {
+            using (SHA1 sha1 = SHA1.Create())
+            {
+                Assert.Throws<ArgumentException>(
+                    () => sha1.ComputeHash(new BadReadStream(BadReadStream.ErrorCondition.TooLargeValueFromRead)));
+                sha1.ComputeHash(new BadReadStream(BadReadStream.ErrorCondition.NegativeValueFromRead));
+            }
+        }
+
+        private sealed class DerivedHMACSHA1 : HMACSHA1
+        {
+            public void ExposedHashCore(byte[] rgb, int ib, int cb)
+            {
+                HashCore(rgb, ib, cb);
+            }
+        }
+
+        private sealed class BadReadStream : Stream
+        {
+            internal enum ErrorCondition
+            {
+                NegativeValueFromRead,
+                TooLargeValueFromRead
+            }
+
+            private readonly ErrorCondition _condition;
+
+            public BadReadStream(ErrorCondition condition)
+            {
+                _condition = condition;
+            }
+
+            public override int Read(byte[] buffer, int offset, int count)
+            {
+                switch (_condition)
+                {
+                    case ErrorCondition.NegativeValueFromRead: return -1;
+                    case ErrorCondition.TooLargeValueFromRead: return buffer.Length + 1;
+                    default: return 0;
+                }
+            }
+
+            public override bool CanRead { get { return true; } }
+            public override bool CanSeek { get { return false; } }
+            public override bool CanWrite { get { return false; } }
+            public override long Length { get { throw new NotSupportedException(); } }
+            public override long Position { get { throw new NotSupportedException(); } set { throw new NotSupportedException(); } }
+            public override void Flush() { }
+            public override long Seek(long offset, SeekOrigin origin) { throw new NotSupportedException(); }
+            public override void SetLength(long value) { throw new NotSupportedException(); }
+            public override void Write(byte[] buffer, int offset, int count) { throw new NotSupportedException(); }
+        }
+    }
+}

src/System.Security.Cryptography.Hashing.Algorithms/tests/System.Security.Cryptography.Hashing.Algorithms.Tests.csproj

@@ -22,6 +22,7 @@
   <ItemGroup>
     <Compile Include="ByteUtils.cs" />
     <Compile Include="HashAlgorithmTest.cs" />
+    <Compile Include="InvalidUsageTests.cs" />
     <Compile Include="HmacSha1Tests.cs" />
     <Compile Include="HmacSha256Tests.cs" />
     <Compile Include="HmacSha384Tests.cs" />