public async Task WorksWhenReadAheadBufferIsNotUsed(int testDataSize)
{
var testData = MockData.MockNetworkStream(testDataSize);
var inst = new RollbackableStream(
testData,
TcpSettings.Default
);
var result = await ReadResult(testDataSize, inst);
Assert.True(testData.ToArray().SequenceEqual(result.ToArray()));
}
public async Task WorksWhenRollingBack(int bytesReadBeforeRollingback, params int[] rollbackBytes)
{
var testData = MockData.MockNetworkStream(4096);
var inst = new RollbackableStream(
testData,
TcpSettings.Default
);
var buffer = new byte[testData.Length];
// Read minimum 4 bytes
int bytesRead = 0;
while (bytesRead < bytesReadBeforeRollingback)
{
bytesRead += await inst.ReadAsync(
buffer,
bytesRead,
(int)testData.Length - bytesRead);
}
// Rollback
foreach (var bytesToRollback in rollbackBytes)
{
bytesRead -= bytesToRollback;
inst.TryRollbackFromIndex(
src: buffer,
srcLength: bytesRead + bytesToRollback,
startIndex: bytesRead
);
}
// Read the rest
while (bytesRead < testData.Length)
{
var t = await inst.ReadAsync(buffer, bytesRead, (int)testData.Length - bytesRead);
if (t == 0)
{
break;
}
bytesRead += t;
}
Assert.Equal(testData.Length, bytesRead);
Assert.True(testData.ToArray().SequenceEqual(buffer));
}
static async Task <MemoryStream> ReadResult(int testDataSize, RollbackableStream inst)
{
var result = new MemoryStream();
var buffer = new byte[4096];
while (result.Length < testDataSize)
{
var bytesRead = await inst.ReadAsync(buffer, 0, buffer.Length);
if (bytesRead == 0)
{
break;
}
result.Write(buffer, 0, bytesRead);
}
return(result);
}
