SabreTools.IO/SabreTools.IO.Extensions.Test/StreamExtensionsTests.cs

using System;
using System.IO;
using System.Text;
using SabreTools.Matching;
using Xunit;

#pragma warning disable IDE0017 // Object initialization can be simplified
#pragma warning disable IDE0230 // Use UTF-8 string literal
namespace SabreTools.IO.Extensions.Test
{
    public class StreamExtensionsTests
    {
        #region AlignToBoundary

        [Fact]
        public void AlignToBoundary_Null_False()
        {
            Stream? stream = null;
            byte alignment = 4;
            bool actual = stream.AlignToBoundary(alignment);
            Assert.False(actual);
        }

        [Fact]
        public void AlignToBoundary_Empty_False()
        {
            Stream? stream = new MemoryStream([]);
            byte alignment = 4;
            bool actual = stream.AlignToBoundary(alignment);
            Assert.False(actual);
        }

        [Fact]
        public void AlignToBoundary_EOF_False()
        {
            Stream? stream = new MemoryStream([0x01, 0x02]);
            byte alignment = 4;

            stream.Position = 1;
            bool actual = stream.AlignToBoundary(alignment);
            Assert.False(actual);
        }

        [Fact]
        public void AlignToBoundary_TooShort_False()
        {
            Stream? stream = new MemoryStream([0x01, 0x02]);
            byte alignment = 4;

            stream.Position = 1;
            bool actual = stream.AlignToBoundary(alignment);
            Assert.False(actual);
        }

        [Fact]
        public void AlignToBoundary_CanAlign_True()
        {
            Stream? stream = new MemoryStream([0x01, 0x02, 0x03, 0x04, 0x05]);
            byte alignment = 4;

            stream.Position = 1;
            bool actual = stream.AlignToBoundary(alignment);
            Assert.True(actual);
        }

        #endregion

        #region BlockCopy

        [Fact]
        public void BlockCopy_NullInput_False()
        {
            Stream? input = null;
            Stream? output = new MemoryStream();
            int blockSize = 8192;

            bool actual = input.BlockCopy(output, blockSize);
            Assert.False(actual);
        }

        [Fact]
        public void BlockCopy_NullOutput_False()
        {
            Stream? input = new MemoryStream();
            Stream? output = null;
            int blockSize = 8192;

            bool actual = input.BlockCopy(output, blockSize);
            Assert.False(actual);
        }

        [Fact]
        public void BlockCopy_UnreadableInput_False()
        {
            Stream? input = new MemoryStream();
            input.Close();
            Stream? output = new MemoryStream();
            int blockSize = 8192;

            bool actual = input.BlockCopy(output, blockSize);
            Assert.False(actual);
        }

        [Fact]
        public void BlockCopy_UnwritableOutput_False()
        {
            Stream? input = new MemoryStream();
            Stream? output = new MemoryStream([], writable: false);
            int blockSize = 8192;

            bool actual = input.BlockCopy(output, blockSize);
            Assert.False(actual);
        }

        [Fact]
        public void BlockCopy_InvalidBlockSize_False()
        {
            Stream? input = new MemoryStream();
            Stream? output = new MemoryStream();
            int blockSize = -1;

            bool actual = input.BlockCopy(output, blockSize);
            Assert.False(actual);
        }

        [Fact]
        public void BlockCopy_ValidInputs_True()
        {
            byte[] inputBytes = [0x00, 0x01, 0x02, 0x03];
            Stream? input = new MemoryStream(inputBytes);
            MemoryStream? output = new MemoryStream();
            int blockSize = 8192;

            bool actual = input.BlockCopy(output, blockSize);
            Assert.True(actual);
            byte[] actualBytes = output.ToArray();
            Assert.True(actualBytes.SequenceEqual(inputBytes));
        }

        #endregion

        #region InterleaveWith

        [Fact]
        public void Interleave_EvenNotExists_False()
        {
            string even = "NOT A REAL PATH";
            string odd = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string output = Guid.NewGuid().ToString();

            bool actual = even.InterleaveWith(odd, output, 1);
            Assert.False(actual);
        }

        [Fact]
        public void Interleave_OddNotExists_False()
        {
            string even = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string odd = "NOT A REAL PATH";
            string output = Guid.NewGuid().ToString();

            bool actual = even.InterleaveWith(odd, output, 1);
            Assert.False(actual);
        }

        [Fact]
        public void Interleave_InvalidValue_False()
        {
            string even = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string odd = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string output = Guid.NewGuid().ToString();

            bool actual = even.InterleaveWith(odd, output, -1);
            Assert.False(actual);
        }

        [Theory]
        [InlineData(1, "TThhiiss  ddooeessnn''tt  mmaattcchh  aannyytthhiinngg")]
        [InlineData(2, "ThThisis d doeoesnsn't't m matatchch a anynyththiningg")]
        [InlineData(4, "ThisThis doe doesn'tsn't mat match ach anythnythinging")]
        [InlineData(8, "This doeThis doesn't matsn't match anythch anythinging")]
        public void Interleave_SameLength_True(int blockSize, string expected)
        {
            string even = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string odd = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string output = Guid.NewGuid().ToString();

            bool actual = even.InterleaveWith(odd, output, blockSize);
            Assert.True(actual);

            string text = File.ReadAllText(output);
            Assert.Equal(expected, text);

            File.Delete(output);
        }

        [Fact]
        public void Interleave_DifferentLength_True()
        {
            string even = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string odd = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "file-to-compress.bin");

            string output = Guid.NewGuid().ToString();

            bool actual = even.InterleaveWith(odd, output, 1);
            Assert.True(actual);

            string text = File.ReadAllText(output);
            Assert.Equal("TThhiiss  diose sjnu'stt  maa tfcihl ea ntyhtahti nhgas a known set of hashes to make sure that everything with hashing is still working as anticipated.", text);

            File.Delete(output);
        }

        #endregion

        #region ReadFrom

        [Theory]
        [InlineData(true)]
        [InlineData(false)]
        public void ReadFrom_Null_Null(bool retainPosition)
        {
            Stream? stream = null;
            byte[]? actual = stream.ReadFrom(0, 1, retainPosition);
            Assert.Null(actual);
        }

        [Theory]
        [InlineData(true)]
        [InlineData(false)]
        public void ReadFrom_NonSeekable_Null(bool retainPosition)
        {
            Stream? stream = new NonSeekableStream();
            byte[]? actual = stream.ReadFrom(0, 1, retainPosition);
            Assert.Null(actual);
        }

        [Theory]
        [InlineData(true)]
        [InlineData(false)]
        public void ReadFrom_Empty_Null(bool retainPosition)
        {
            Stream? stream = new MemoryStream([]);
            byte[]? actual = stream.ReadFrom(0, 1, retainPosition);
            Assert.Null(actual);
        }

        [Theory]
        [InlineData(-1, true)]
        [InlineData(2048, true)]
        [InlineData(-1, false)]
        [InlineData(2048, false)]
        public void ReadFrom_InvalidOffset_Null(long offset, bool retainPosition)
        {
            Stream? stream = new MemoryStream(new byte[1024]);
            byte[]? actual = stream.ReadFrom(offset, 1, retainPosition);
            Assert.Null(actual);
        }

        [Theory]
        [InlineData(-1, true)]
        [InlineData(2048, true)]
        [InlineData(-1, false)]
        [InlineData(2048, false)]
        public void ReadFrom_InvalidLength_Null(int length, bool retainPosition)
        {
            Stream? stream = new MemoryStream(new byte[1024]);
            byte[]? actual = stream.ReadFrom(0, length, retainPosition);
            Assert.Null(actual);
        }

        [Theory]
        [InlineData(true)]
        [InlineData(false)]
        public void ReadFrom_Valid_Filled(bool retainPosition)
        {
            Stream? stream = new MemoryStream(new byte[1024]);
            byte[]? actual = stream.ReadFrom(0, 512, retainPosition);

            Assert.NotNull(actual);
            Assert.Equal(512, actual.Length);

            if (retainPosition)
                Assert.Equal(0, stream.Position);
            else
                Assert.Equal(512, stream.Position);
        }

        #endregion

        #region ReadStringsFrom

        [Fact]
        public void ReadStringsFrom_Null_Null()
        {
            Stream? stream = null;
            var actual = stream.ReadStringsFrom(0, 1, 3);
            Assert.Null(actual);
        }

        [Fact]
        public void ReadStringsFrom_NonSeekable_Null()
        {
            Stream? stream = new NonSeekableStream();
            var actual = stream.ReadStringsFrom(0, 1, 3);
            Assert.Null(actual);
        }

        [Fact]
        public void ReadStringsFrom_Empty_Null()
        {
            Stream? stream = new MemoryStream([]);
            var actual = stream.ReadStringsFrom(0, 1, 3);
            Assert.Null(actual);
        }

        [Theory]
        [InlineData(-1)]
        [InlineData(0)]
        [InlineData(2048)]
        public void ReadStringsFrom_InvalidLimit_Empty(int charLimit)
        {
            Stream? stream = new MemoryStream(new byte[1024]);
            var actual = stream.ReadStringsFrom(0, 1024, charLimit);
            Assert.NotNull(actual);
            Assert.Empty(actual);
        }

        [Fact]
        public void ReadStringsFrom_NoValidStrings_Empty()
        {
            Stream? stream = new MemoryStream(new byte[1024]);
            var actual = stream.ReadStringsFrom(0, 1024, 4);
            Assert.NotNull(actual);
            Assert.Empty(actual);
        }

        [Fact]
        public void ReadStringsFrom_AsciiStrings_Filled()
        {
            byte[]? bytes =
            [
                .. Encoding.ASCII.GetBytes("TEST"),
                .. new byte[] { 0x00 },
                .. Encoding.ASCII.GetBytes("TWO"),
                .. new byte[] { 0x00 },
                .. Encoding.ASCII.GetBytes("DATA"),
                .. new byte[] { 0x00 },
            ];
            Stream? stream = new MemoryStream(bytes);
            var actual = stream.ReadStringsFrom(0, bytes.Length, 4);
            Assert.NotNull(actual);
            Assert.Equal(2, actual.Count);
        }

        [Fact]
        public void ReadStringsFrom_Latin1Strings_Filled()
        {
            byte[]? bytes =
            [
                .. Encoding.Latin1.GetBytes("TEST"),
                .. new byte[] { 0x00 },
                .. Encoding.Latin1.GetBytes("TWO"),
                .. new byte[] { 0x00 },
                .. Encoding.Latin1.GetBytes("DATA"),
                .. new byte[] { 0x00 },
            ];
            Stream? stream = new MemoryStream(bytes);
            var actual = stream.ReadStringsFrom(0, bytes.Length, 4);
            Assert.NotNull(actual);
            Assert.Equal(2, actual.Count);
        }

        [Fact]
        public void ReadStringsFrom_UTF16_Filled()
        {
            byte[]? bytes =
            [
                .. Encoding.Unicode.GetBytes("TEST"),
                .. new byte[] { 0x00 },
                .. Encoding.Unicode.GetBytes("TWO"),
                .. new byte[] { 0x00 },
                .. Encoding.Unicode.GetBytes("DATA"),
                .. new byte[] { 0x00 },
            ];
            Stream? stream = new MemoryStream(bytes);
            var actual = stream.ReadStringsFrom(0, bytes.Length, 4);
            Assert.NotNull(actual);
            Assert.Equal(2, actual.Count);
        }

        [Fact]
        public void ReadStringsFrom_Mixed_Filled()
        {
            byte[]? bytes =
            [
                .. Encoding.ASCII.GetBytes("TEST1"),
                .. new byte[] { 0x00 },
                .. Encoding.ASCII.GetBytes("TWO1"),
                .. new byte[] { 0x00 },
                .. Encoding.ASCII.GetBytes("DATA1"),
                .. new byte[] { 0x00 },
                .. Encoding.Latin1.GetBytes("TEST2"),
                .. new byte[] { 0x00 },
                .. Encoding.Latin1.GetBytes("TWO2"),
                .. new byte[] { 0x00 },
                .. Encoding.Latin1.GetBytes("DATA2"),
                .. new byte[] { 0x00 },
                .. Encoding.Unicode.GetBytes("TEST3"),
                .. new byte[] { 0x00 },
                .. Encoding.Unicode.GetBytes("TWO3"),
                .. new byte[] { 0x00 },
                .. Encoding.Unicode.GetBytes("DATA3"),
                .. new byte[] { 0x00 },
            ];
            Stream? stream = new MemoryStream(bytes);
            var actual = stream.ReadStringsFrom(0, bytes.Length, 5);
            Assert.NotNull(actual);
            Assert.Equal(6, actual.Count);
        }

        #endregion

        #region SeekIfPossible

        [Fact]
        public void SeekIfPossible_NonSeekable_CurrentPosition()
        {
            var stream = new NonSeekableStream();
            long actual = stream.SeekIfPossible(0);
            Assert.Equal(8, actual);
        }

        [Fact]
        public void SeekIfPossible_NonPositionable_InvalidPosition()
        {
            var stream = new NonPositionableStream();
            long actual = stream.SeekIfPossible(0);
            Assert.Equal(-1, actual);
        }

        [Fact]
        public void SeekIfPossible_HiddenNonSeekable_InvalidPosition()
        {
            var stream = new HiddenNonSeekableStream();
            long actual = stream.SeekIfPossible(0);
            Assert.Equal(-1, actual);
        }

        [Fact]
        public void SeekIfPossible_NonNegative_ValidPosition()
        {
            var stream = new MemoryStream(new byte[16], 0, 16, false, true);
            long actual = stream.SeekIfPossible(5);
            Assert.Equal(5, actual);
        }

        [Fact]
        public void SeekIfPossible_Negative_ValidPosition()
        {
            var stream = new MemoryStream(new byte[16], 0, 16, false, true);
            long actual = stream.SeekIfPossible(-3);
            Assert.Equal(13, actual);
        }

        [Theory]
        [InlineData(SeekOrigin.Begin)]
        [InlineData(SeekOrigin.Current)]
        [InlineData(SeekOrigin.End)]
        public void SeekIfPossible_NonSeekable_OriginTest(SeekOrigin origin)
        {
            var stream = new NonSeekableStream();
            long actual = stream.SeekIfPossible(0, origin);
            Assert.Equal(8, actual);
        }

        [Theory]
        [InlineData(SeekOrigin.Begin)]
        [InlineData(SeekOrigin.Current)]
        [InlineData(SeekOrigin.End)]
        public void SeekIfPossible_NonPositionable_OriginTest(SeekOrigin origin)
        {
            var stream = new NonPositionableStream();
            long actual = stream.SeekIfPossible(0, origin);
            Assert.Equal(-1, actual);
        }

        [Theory]
        [InlineData(SeekOrigin.Begin)]
        [InlineData(SeekOrigin.Current)]
        [InlineData(SeekOrigin.End)]
        public void SeekIfPossible_HiddenNonSeekable_OriginTest(SeekOrigin origin)
        {
            var stream = new HiddenNonSeekableStream();
            long actual = stream.SeekIfPossible(0, origin);
            Assert.Equal(-1, actual);
        }

        [Theory]
        [InlineData(SeekOrigin.Begin, 5, 5)]
        [InlineData(SeekOrigin.Current, 5, 7)]
        [InlineData(SeekOrigin.End, -5, 11)]
        public void SeekIfPossible_Seekable_OriginTest(SeekOrigin origin, long offset, long expected)
        {
            var stream = new MemoryStream(new byte[16], 0, 16, false, true);
            stream.Position = 2;

            long actual = stream.SeekIfPossible(offset, origin);
            Assert.Equal(expected, actual);
        }

        #endregion

        #region SegmentValid

        [Fact]
        public void SegmentValid_Null_False()
        {
            Stream? stream = null;
            bool actual = stream.SegmentValid(0, 1);
            Assert.False(actual);
        }

        [Theory]
        [InlineData(-1)]
        [InlineData(2048)]
        public void SegmentValid_InvalidOffset_False(long offset)
        {
            Stream? stream = new MemoryStream(new byte[1024]);
            bool actual = stream.SegmentValid(offset, 1);
            Assert.False(actual);
        }

        [Theory]
        [InlineData(-1)]
        [InlineData(2048)]
        public void SegmentValid_InvalidLength_False(int length)
        {
            Stream? stream = new MemoryStream(new byte[1024]);
            bool actual = stream.SegmentValid(0, length);
            Assert.False(actual);
        }

        [Fact]
        public void SegmentValid_ValidSegment_True()
        {
            Stream? stream = new MemoryStream(new byte[1024]);
            bool actual = stream.SegmentValid(0, 1024);
            Assert.True(actual);
        }

        #endregion

        #region SplitToChunks

        [Fact]
        public void SplitToChunks_EmptyFileName_False()
        {
            string input = string.Empty;
            string outputDir = string.Empty;
            int size = 1;

            bool actual = input.SplitToChunks(outputDir, size);
            Assert.False(actual);
        }

        [Fact]
        public void SplitToChunks_InvalidFile_False()
        {
            string input = "INVALID";
            string outputDir = string.Empty;
            int size = 1;

            bool actual = input.SplitToChunks(outputDir, size);
            Assert.False(actual);
        }

        [Fact]
        public void SplitToChunks_InvalidSize_False()
        {
            string input = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string outputDir = string.Empty;
            int size = 0;

            bool actual = input.SplitToChunks(outputDir, size);
            Assert.False(actual);
        }

        [Fact]
        public void SplitToChunks_Valid_True()
        {
            string input = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string outputDir = Guid.NewGuid().ToString();
            int size = 16;

            bool actual = input.SplitToChunks(outputDir, size);
            Assert.True(actual);

            Assert.Equal(2, Directory.GetFiles(outputDir).Length);

            string baseFilename = Path.GetFileName(input);
            string text = File.ReadAllText(Path.Combine(outputDir, $"{baseFilename}.0"));
            Assert.Equal("This doesn't mat", text);
            text = File.ReadAllText(Path.Combine(outputDir, $"{baseFilename}.1"));
            Assert.Equal("ch anything", text);

            File.Delete($"{baseFilename}.0");
            File.Delete($"{baseFilename}.1");
        }

        #endregion

        #region SplitToEvenOdd

        [Fact]
        public void SplitToEvenOdd_EmptyFileName_False()
        {
            string input = string.Empty;
            string even = string.Empty;
            string odd = string.Empty;
            bool actual = input.SplitToEvenOdd(even, odd, 1);
            Assert.False(actual);
        }

        [Fact]
        public void SplitToEvenOdd_InvalidFile_False()
        {
            string input = "INVALID";
            string even = string.Empty;
            string odd = string.Empty;
            bool actual = input.SplitToEvenOdd(even, odd, 1);
            Assert.False(actual);
        }

        [Fact]
        public void SplitToEvenOdd_InvalidValue_False()
        {
            string input = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string baseFileName = Guid.NewGuid().ToString();
            string even = $"{baseFileName}.even";
            string odd = $"{baseFileName}.odd";

            bool actual = input.SplitToEvenOdd(even, odd, -1);
            Assert.False(actual);
        }

        [Theory]
        [InlineData(1, "Ti os' ac ntig", "hsdentmthayhn")]
        [InlineData(2, "Th dsn mchnyin", "isoe'tat athg")]
        [InlineData(4, "Thissn'tch aing", " doe matnyth")]
        [InlineData(8, "This doech anyth", "sn't mating")]
        public void SplitToEvenOdd_ValidFile_True(int blockSize, string expectedEven, string expectedOdd)
        {
            string input = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string baseFileName = Guid.NewGuid().ToString();
            string even = $"{baseFileName}.even";
            string odd = $"{baseFileName}.odd";

            bool actual = input.SplitToEvenOdd(even, odd, blockSize);
            Assert.True(actual);

            string text = File.ReadAllText(even);
            Assert.Equal(expectedEven, text);
            text = File.ReadAllText(odd);
            Assert.Equal(expectedOdd, text);

            File.Delete(even);
            File.Delete(odd);
        }

        [Fact]
        public void SplitToEvenOdd_ValidFile_SameEvenOdd_False()
        {
            string input = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string baseFileName = Guid.NewGuid().ToString();
            string evenOdd = $"{baseFileName}.all";

            bool actual = input.SplitToEvenOdd(evenOdd, evenOdd, 4);
            Assert.False(actual);

            File.Delete(evenOdd);
        }

        #endregion

        #region Swap

        [Fact]
        public void Swap_EmptyFileName_False()
        {
            string input = string.Empty;
            string output = string.Empty;
            bool actual = input.Swap(output, SwapOperation.Byteswap);
            Assert.False(actual);
        }

        [Fact]
        public void Swap_InvalidFile_False()
        {
            string input = "INVALID";
            string output = string.Empty;
            bool actual = input.Swap(output, SwapOperation.Byteswap);
            Assert.False(actual);
        }

        [Fact]
        public void Swap_InvalidType_False()
        {
            string input = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string output = Guid.NewGuid().ToString();

            bool actual = input.Swap(output, (SwapOperation)int.MaxValue);
            Assert.False(actual);
        }

        [Fact]
        public void Swap_Valid_True()
        {
            string input = Path.Combine(Environment.CurrentDirectory, "TestData", "Path", "ascii.txt");
            string output = Guid.NewGuid().ToString();

            // Bitswap
            bool actual = input.Swap(output, SwapOperation.Bitswap);
            Assert.True(actual);
            byte[] actualBytes = File.ReadAllBytes(output);
            Assert.True(new byte[] { 0x2A, 0x16, 0x96, 0xCE, 0x04, 0x26, 0xF6, 0xA6, 0xCE, 0x76, 0xE4, 0x2E, 0x04, 0xB6, 0x86, 0x2E, 0xC6, 0x16, 0x04, 0x86, 0x76, 0x9E, 0x2E, 0x16, 0x96, 0x76, 0xE6 }.EqualsExactly(actualBytes));

            // Byteswap
            actual = input.Swap(output, SwapOperation.Byteswap);
            Assert.True(actual);
            actualBytes = File.ReadAllBytes(output);
            Assert.True(new byte[] { 0x68, 0x54, 0x73, 0x69, 0x64, 0x20, 0x65, 0x6F, 0x6E, 0x73, 0x74, 0x27, 0x6D, 0x20, 0x74, 0x61, 0x68, 0x63, 0x61, 0x20, 0x79, 0x6E, 0x68, 0x74, 0x6E, 0x69, 0x67 }.EqualsExactly(actualBytes));

            // Wordswap
            actual = input.Swap(output, SwapOperation.Wordswap);
            Assert.True(actual);
            actualBytes = File.ReadAllBytes(output);
            Assert.True(new byte[] { 0x69, 0x73, 0x54, 0x68, 0x6F, 0x65, 0x20, 0x64, 0x27, 0x74, 0x73, 0x6E, 0x61, 0x74, 0x20, 0x6D, 0x20, 0x61, 0x63, 0x68, 0x74, 0x68, 0x6E, 0x79, 0x69, 0x6E, 0x67 }.EqualsExactly(actualBytes));

            // WordByteswap
            actual = input.Swap(output, SwapOperation.WordByteswap);
            Assert.True(actual);
            actualBytes = File.ReadAllBytes(output);
            Assert.True(new byte[] { 0x73, 0x69, 0x68, 0x54, 0x65, 0x6F, 0x64, 0x20, 0x74, 0x27, 0x6E, 0x73, 0x74, 0x61, 0x6D, 0x20, 0x61, 0x20, 0x68, 0x63, 0x68, 0x74, 0x79, 0x6E, 0x69, 0x6E, 0x67 }.EqualsExactly(actualBytes));

            File.Delete(output);
        }

        #endregion

        /// <summary>
        /// Represents a hidden non-seekable stream
        /// </summary>
        private class HiddenNonSeekableStream : Stream
        {
            public override bool CanRead => true;

            public override bool CanSeek => true;

            public override bool CanWrite => true;

            public override long Length => 16;

            public override long Position { get => 8; set => throw new NotSupportedException(); }

            public override void Flush()
            {
                throw new NotImplementedException();
            }

            public override int Read(byte[] buffer, int offset, int count)
            {
                throw new NotImplementedException();
            }

            public override long Seek(long offset, SeekOrigin origin)
            {
                throw new NotImplementedException();
            }

            public override void SetLength(long value)
            {
                throw new NotImplementedException();
            }

            public override void Write(byte[] buffer, int offset, int count)
            {
                throw new NotImplementedException();
            }
        }

        /// <summary>
        /// Represents a non-seekable stream
        /// </summary>
        private class NonSeekableStream : Stream
        {
            public override bool CanRead => true;

            public override bool CanSeek => false;

            public override bool CanWrite => true;

            public override long Length => 16;

            public override long Position { get => 8; set => throw new NotSupportedException(); }

            public override void Flush()
            {
                throw new NotImplementedException();
            }

            public override int Read(byte[] buffer, int offset, int count)
            {
                throw new NotImplementedException();
            }

            public override long Seek(long offset, SeekOrigin origin)
            {
                throw new NotImplementedException();
            }

            public override void SetLength(long value)
            {
                throw new NotImplementedException();
            }

            public override void Write(byte[] buffer, int offset, int count)
            {
                throw new NotImplementedException();
            }
        }

        /// <summary>
        /// Represents a non-seekable, non-positionable stream
        /// </summary>
        private class NonPositionableStream : Stream
        {
            public override bool CanRead => true;

            public override bool CanSeek => false;

            public override bool CanWrite => true;

            public override long Length => 16;

            public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }

            public override void Flush()
            {
                throw new NotImplementedException();
            }

            public override int Read(byte[] buffer, int offset, int count)
            {
                throw new NotImplementedException();
            }

            public override long Seek(long offset, SeekOrigin origin)
            {
                throw new NotImplementedException();
            }

            public override void SetLength(long value)
            {
                throw new NotImplementedException();
            }

            public override void Write(byte[] buffer, int offset, int count)
            {
                throw new NotImplementedException();
            }
        }
    }
}