public void BackpatchSize_should_backpatch_the_size(
[Values(0, 1, 5)]
int startPosition)
{
var bytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
var length = bytes.Length - startPosition;
var expectedBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
Array.Copy(BitConverter.GetBytes(length), 0, expectedBytes, startPosition, 4);
using (var memoryStream = new MemoryStream())
using (var stream = new BsonStreamAdapter(memoryStream))
{
stream.WriteBytes(bytes, 0, bytes.Length);
var position = stream.Position;
stream.BackpatchSize(startPosition);
memoryStream.ToArray().Should().Equal(expectedBytes);
stream.Position.Should().Be(position);
}
}