Add TextReader/Writer Memory-based virtuals

src/System.IO/tests/StringReader/StringReader.CtorTests.cs

@@ -8,7 +8,7 @@
 
 namespace System.IO.Tests
 {
-    public class ReaderTests
+    public partial class StringReaderTests
     {
         [Fact]
         public static void StringReaderWithNullString()

src/System.IO/tests/StringReader/StringReaderTests.netcoreapp.cs

@@ -0,0 +1,122 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace System.IO.Tests
+{
+    public partial class StringReaderTests
+    {
+        [Fact]
+        public void ReadSpan_Success()
+        {
+            string input = "abcdef";
+            var reader = new StringReader(input);
+            Span<char> s = new char[2];
+
+            Assert.Equal(2, reader.Read(s));
+            Assert.Equal("ab", new string(s.ToArray()));
+
+            Assert.Equal(1, reader.Read(s.Slice(0, 1)));
+            Assert.Equal("cb", new string(s.ToArray()));
+
+            Assert.Equal(2, reader.Read(s));
+            Assert.Equal("de", new string(s.ToArray()));
+
+            Assert.Equal(1, reader.Read(s));
+            Assert.Equal("f", new string(s.Slice(0, 1).ToArray()));
+
+            Assert.Equal(0, reader.Read(s));
+        }
+
+        [Fact]
+        public void ReadBlockSpan_Success()
+        {
+            string input = "abcdef";
+            var reader = new StringReader(input);
+            Span<char> s = new char[2];
+
+            Assert.Equal(2, reader.ReadBlock(s));
+            Assert.Equal("ab", new string(s.ToArray()));
+
+            Assert.Equal(1, reader.ReadBlock(s.Slice(0, 1)));
+            Assert.Equal("cb", new string(s.ToArray()));
+
+            Assert.Equal(2, reader.ReadBlock(s));
+            Assert.Equal("de", new string(s.ToArray()));
+
+            Assert.Equal(1, reader.ReadBlock(s));
+            Assert.Equal("f", new string(s.Slice(0, 1).ToArray()));
+
+            Assert.Equal(0, reader.ReadBlock(s));
+        }
+
+        [Fact]
+        public async Task ReadMemoryAsync_Success()
+        {
+            string input = "abcdef";
+            var reader = new StringReader(input);
+            Memory<char> m = new char[2];
+
+            Assert.Equal(2, await reader.ReadAsync(m));
+            Assert.Equal("ab", new string(m.ToArray()));
+
+            Assert.Equal(1, await reader.ReadAsync(m.Slice(0, 1)));
+            Assert.Equal("cb", new string(m.ToArray()));
+
+            Assert.Equal(2, await reader.ReadAsync(m));
+            Assert.Equal("de", new string(m.ToArray()));
+
+            Assert.Equal(1, await reader.ReadAsync(m));
+            Assert.Equal("f", new string(m.Slice(0, 1).ToArray()));
+
+            Assert.Equal(0, await reader.ReadAsync(m));
+        }
+
+        [Fact]
+        public async Task ReadBlockMemoryAsync_Success()
+        {
+            string input = "abcdef";
+            var reader = new StringReader(input);
+            Memory<char> m = new char[2];
+
+            Assert.Equal(2, await reader.ReadBlockAsync(m));
+            Assert.Equal("ab", new string(m.ToArray()));
+
+            Assert.Equal(1, await reader.ReadBlockAsync(m.Slice(0, 1)));
+            Assert.Equal("cb", new string(m.ToArray()));
+
+            Assert.Equal(2, await reader.ReadBlockAsync(m));
+            Assert.Equal("de", new string(m.ToArray()));
+
+            Assert.Equal(1, await reader.ReadBlockAsync(m));
+            Assert.Equal("f", new string(m.Slice(0, 1).ToArray()));
+
+            Assert.Equal(0, await reader.ReadBlockAsync(m));
+        }
+
+        [Fact]
+        public void Disposed_ThrowsException()
+        {
+            var reader = new StringReader("abc");
+            reader.Dispose();
+
+            Assert.Throws<ObjectDisposedException>(() => reader.Read(Span<char>.Empty));
+            Assert.Throws<ObjectDisposedException>(() => reader.ReadBlock(Span<char>.Empty));
+            Assert.Throws<ObjectDisposedException>(() => { reader.ReadAsync(Memory<char>.Empty); });
+            Assert.Throws<ObjectDisposedException>(() => { reader.ReadBlockAsync(Memory<char>.Empty); });
+        }
+
+        [Fact]
+        public async Task Precanceled_ThrowsException()
+        {
+            var reader = new StringReader("abc");
+
+            await Assert.ThrowsAnyAsync<OperationCanceledException>(() => reader.ReadAsync(Memory<char>.Empty, new CancellationToken(true)).AsTask());
+            await Assert.ThrowsAnyAsync<OperationCanceledException>(() => reader.ReadBlockAsync(Memory<char>.Empty, new CancellationToken(true)).AsTask());
+        }
+    }
+}

src/System.IO/tests/StringWriter/StringWriterTests.cs

@@ -11,7 +11,7 @@
 
 namespace System.IO.Tests
 {
-    public class StringWriterTests
+    public partial class StringWriterTests
     {
         static int[] iArrInvalidValues = new int[] { -1, -2, -100, -1000, -10000, -100000, -1000000, -10000000, -100000000, -1000000000, int.MinValue, short.MinValue };
         static int[] iArrLargeValues = new int[] { int.MaxValue, int.MaxValue - 1, int.MaxValue / 2, int.MaxValue / 10, int.MaxValue / 100 };

src/System.IO/tests/StringWriter/StringWriterTests.netcoreapp.cs

@@ -0,0 +1,40 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Threading;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace System.IO.Tests
+{
+    public partial class StringWriterTests
+    {
+        [Fact]
+        public async Task WriteSpanMemory_Success()
+        {
+            var sw = new StringWriter();
+
+            sw.Write((Span<char>)new char[0]);
+            sw.Write((Span<char>)new char[] { 'a' });
+            sw.Write((Span<char>)new char[] { 'b', 'c', 'd' });
+            sw.WriteLine((Span<char>)new char[] { 'e' });
+
+            await sw.WriteAsync((ReadOnlyMemory<char>)new char[0]);
+            await sw.WriteAsync((ReadOnlyMemory<char>)new char[] { 'f' });
+            await sw.WriteAsync((ReadOnlyMemory<char>)new char[] { 'g', 'h', 'i' });
+            await sw.WriteLineAsync((ReadOnlyMemory<char>)new char[] { 'j' });
+
+            Assert.Equal("abcde" + Environment.NewLine + "fghij" + Environment.NewLine, sw.ToString());
+        }
+
+        [Fact]
+        public async Task Precanceled_ThrowsException()
+        {
+            var writer = new StringWriter();
+
+            await Assert.ThrowsAnyAsync<OperationCanceledException>(() => writer.WriteAsync(Memory<char>.Empty, new CancellationToken(true)));
+            await Assert.ThrowsAnyAsync<OperationCanceledException>(() => writer.WriteLineAsync(Memory<char>.Empty, new CancellationToken(true)));
+        }
+    }
+}

src/System.IO/tests/System.IO.Tests.csproj

@@ -51,9 +51,11 @@
     <Compile Include="Stream\Stream.Methods.cs" />
     <Compile Include="Stream\Stream.TestLeaveOpen.cs" />
     <Compile Include="Stream\Stream.TimeoutTests.cs" />
+    <Compile Include="StringReader\StringReaderTests.netcoreapp.cs" Condition="'$(TargetGroup)' == 'netcoreapp'" />
     <Compile Include="StringReader\StringReader.CtorTests.cs" />
+    <Compile Include="StringWriter\StringWriterTests.netcoreapp.cs" Condition="'$(TargetGroup)' == 'netcoreapp'" />
     <Compile Include="StringWriter\StringWriterTests.cs" />
-    <Compile Include="$(CommonTestPath)\System\Buffers\NativeOwnedMemory.cs"  Condition="'$(TargetGroup)' == 'netcoreapp'" >
+    <Compile Include="$(CommonTestPath)\System\Buffers\NativeOwnedMemory.cs" Condition="'$(TargetGroup)' == 'netcoreapp'">
       <Link>Common\System\Buffers\NativeOwnedMemory.cs</Link>
     </Compile>
     <Compile Include="$(CommonTestPath)\System\IO\CallTrackingStream.cs">
@@ -77,4 +79,4 @@
     <EmbeddedResource Include="Resources\$(AssemblyName).rd.xml" />
   </ItemGroup>
   <Import Project="$([MSBuild]::GetDirectoryNameOfFileAbove($(MSBuildThisFileDirectory), dir.targets))\dir.targets" />
-</Project>
+</Project>

src/System.IO/tests/TextWriter/TextWriterTests.netcoreapp.cs

@@ -2,8 +2,6 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Collections.Generic;
-using System.Linq;
 using System.Threading.Tasks;
 using Xunit;
 
@@ -32,5 +30,27 @@ public void WriteLineCharSpanTest()
                 Assert.Equal(new string(rs) + tw.NewLine, tw.Text);
             }
         }
+
+        [Fact]
+        public async Task WriteCharMemoryTest()
+        {
+            using (CharArrayTextWriter tw = NewTextWriter)
+            {
+                var rs = new Memory<char>(TestDataProvider.CharData, 4, 6);
+                await tw.WriteAsync(rs);
+                Assert.Equal(new string(rs.Span), tw.Text);
+            }
+        }
+
+        [Fact]
+        public async Task WriteLineCharMemoryTest()
+        {
+            using (CharArrayTextWriter tw = NewTextWriter)
+            {
+                var rs = new Memory<char>(TestDataProvider.CharData, 4, 6);
+                await tw.WriteLineAsync(rs);
+                Assert.Equal(new string(rs.Span) + tw.NewLine, tw.Text);
+            }
+        }
     }
 }