public void Write()
{
MemoryStream innerStream = new MemoryStream();
Stream transcodingStream = Encoding.CreateTranscodingStream(
innerStream,
innerStreamEncoding: ErrorCheckingUnicodeEncoding /* throws on error */,
outerStreamEncoding: Encoding.UTF8 /* performs substition */,
leaveOpen: true);
// First, test Write(byte[], int, int)
transcodingStream.Write(Encoding.UTF8.GetBytes("abcdefg"), 2, 3);
Assert.Equal("cde", ErrorCheckingUnicodeEncoding.GetString(innerStream.ToArray()));
// Then test WriteByte(byte)
transcodingStream.WriteByte((byte)'z');
Assert.Equal("cdez", ErrorCheckingUnicodeEncoding.GetString(innerStream.ToArray()));
// We'll write U+00E0 (utf-8: [C3 A0]) byte-by-byte.
// We shouldn't flush any intermediate bytes.
transcodingStream.WriteByte((byte)0xC3);
Assert.Equal("cdez", ErrorCheckingUnicodeEncoding.GetString(innerStream.ToArray()));
transcodingStream.WriteByte((byte)0xA0);
Assert.Equal("cdez\u00E0", ErrorCheckingUnicodeEncoding.GetString(innerStream.ToArray()));
innerStream.SetLength(0); // reset inner stream
// Then test Write(ROS<byte>), once with a short string and once with a long string
string asciiString = GetVeryLongAsciiString(128);
byte[] asciiBytesAsUtf8 = Encoding.UTF8.GetBytes(asciiString);
transcodingStream.Write(asciiBytesAsUtf8.AsSpan());
Assert.Equal(asciiString, ErrorCheckingUnicodeEncoding.GetString(innerStream.ToArray()));
innerStream.SetLength(0); // reset inner stream
asciiString = GetVeryLongAsciiString(16 * 1024 * 1024);
asciiBytesAsUtf8 = Encoding.UTF8.GetBytes(asciiString);
transcodingStream.Write(asciiBytesAsUtf8.AsSpan());
Assert.Equal(asciiString, ErrorCheckingUnicodeEncoding.GetString(innerStream.ToArray()));
innerStream.SetLength(0); // reset inner stream
// Close the outer stream and ensure no leftover data was written to the inner stream
transcodingStream.Close();
Assert.Equal(0, innerStream.Position);
}
public async Task WriteAsync()
{
MemoryStream sink = new MemoryStream();
CancellationToken expectedFlushAsyncCancellationToken = new CancellationTokenSource().Token;
CancellationToken expectedWriteAsyncCancellationToken = new CancellationTokenSource().Token;
var innerStreamMock = new Mock <Stream>(MockBehavior.Strict);
innerStreamMock.Setup(o => o.CanWrite).Returns(true);
innerStreamMock.Setup(o => o.WriteAsync(It.IsAny <ReadOnlyMemory <byte> >(), expectedWriteAsyncCancellationToken))
.Returns <ReadOnlyMemory <byte>, CancellationToken>(sink.WriteAsync);
innerStreamMock.Setup(o => o.FlushAsync(expectedFlushAsyncCancellationToken)).Returns(Task.CompletedTask);
Stream transcodingStream = Encoding.CreateTranscodingStream(
innerStreamMock.Object,
innerStreamEncoding: ErrorCheckingUnicodeEncoding,
outerStreamEncoding: Encoding.UTF8 /* performs U+FFFD substition */,
leaveOpen: true);
// First, test WriteAsync(byte[], int, int, CancellationToken)
await transcodingStream.WriteAsync(Encoding.UTF8.GetBytes("abcdefg"), 2, 3, expectedWriteAsyncCancellationToken);
Assert.Equal("cde", ErrorCheckingUnicodeEncoding.GetString(sink.ToArray()));
// We'll write U+00E0 (utf-8: [C3 A0]) byte-by-byte.
// We shouldn't flush any intermediate bytes.
await transcodingStream.WriteAsync(new byte[] { 0xC3, 0xA0 }, 0, 1, expectedWriteAsyncCancellationToken);
await transcodingStream.FlushAsync(expectedFlushAsyncCancellationToken);
Assert.Equal("cde", ErrorCheckingUnicodeEncoding.GetString(sink.ToArray()));
await transcodingStream.WriteAsync(new byte[] { 0xC3, 0xA0 }, 1, 1, expectedWriteAsyncCancellationToken);
Assert.Equal("cde\u00E0", ErrorCheckingUnicodeEncoding.GetString(sink.ToArray()));
sink.SetLength(0); // reset sink
// Then test WriteAsync(ROM<byte>, CancellationToken), once with a short string and once with a long string
string asciiString = GetVeryLongAsciiString(128);
byte[] asciiBytesAsUtf8 = Encoding.UTF8.GetBytes(asciiString);
await transcodingStream.WriteAsync(asciiBytesAsUtf8.AsMemory(), expectedWriteAsyncCancellationToken);
Assert.Equal(asciiString, ErrorCheckingUnicodeEncoding.GetString(sink.ToArray()));
sink.SetLength(0); // reset sink
asciiString = GetVeryLongAsciiString(16 * 1024 * 1024);
asciiBytesAsUtf8 = Encoding.UTF8.GetBytes(asciiString);
await transcodingStream.WriteAsync(asciiBytesAsUtf8.AsMemory(), expectedWriteAsyncCancellationToken);
Assert.Equal(asciiString, ErrorCheckingUnicodeEncoding.GetString(sink.ToArray()));
sink.SetLength(0); // reset sink
// Close the outer stream and ensure no leftover data was written to the inner stream
ValueTask actualDisposeTask = transcodingStream.DisposeAsync();
Assert.Equal(default(ValueTask), actualDisposeTask); // should've completed synchronously
Assert.Equal(0, sink.Position);
}
