Bug: Filesystem serialization & deserialization works with fileSystem.GetFile(path).Contents) but not fileSystem.File.ReadAllBytes(path));

[darl2ng]

For now directories and files are restored but reading file content raises null exception:

// save:
IFormatter formatter = new BinaryFormatter();
            Stream stream = new FileStream(Path.GetTempPath() + "test.io", FileMode.Create, FileAccess.Write);
            formatter.Serialize(stream, fileSystem);
            stream.Close();

// reload
IFormatter formatter = new BinaryFormatter();
            Stream stream = new FileStream(Path.GetTempPath() + FS_FILENAME, FileMode.Open, FileAccess.Read);
            IFileSystem fileSystem = (MockFileSystem)formatter.Deserialize(stream);
            stream.Close();
            return fileSystem;

// read
fileSystem.File.ReadAllBytes(fileInfo.FullName); // => exception

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[fgreinacher]

Thanks for the report! Would be more actionable if you'd include the callstack for the exception.

[darl2ng]

namespace System.IO.Abstractions.TestingHelpers.Tests
{
using NUnit.Framework;
using System.Reflection;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
using Text;
using XFS = MockUnixSupport;
[TestFixture]
class MockFileSystemSerializationTests
{

    const string FS_FILENAME = @"test.fs";

    [Test]
    public void SerializationTexts()
    {
        // Arrange
        string path = XFS.Path(@"c:\something\demo.txt");

        var content = "Hello there!" + Environment.NewLine + "Second line!" + Environment.NewLine;

        var fileSystem = new MockFileSystem();
        fileSystem.AddDirectory(XFS.Path(@"c:\something"));

        fileSystem.File.WriteAllText(path, content);

        //Act
        SaveFileSystem(fileSystem);
        fileSystem = (MockFileSystem) LoadFileSystem();

        //Clear
        ClearFileSystem();

        // Assert
        Assert.AreEqual(
            content,
            fileSystem.GetFile(path).Contents);
        Assert.AreEqual(
            content,
            fileSystem.File.ReadAllText(path));

    }
    [Test]
    public void SerializationBytes()
    {
        // Arrange
        string path = XFS.Path(@"c:\something\demo.txt");

        var content = "Hello there!" + Environment.NewLine + "Second line!" + Environment.NewLine;
        var expected = Encoding.ASCII.GetBytes(content); //Convert a C# string to a byte array

        var fileSystem = new MockFileSystem();
        fileSystem.AddDirectory(XFS.Path(@"c:\something"));

        fileSystem.File.WriteAllBytes(path, expected);

        //Act
        SaveFileSystem(fileSystem);
        fileSystem = (MockFileSystem)LoadFileSystem();

        //Clear
        ClearFileSystem();

        // Assert
        Assert.AreEqual(
            expected,
            fileSystem.GetFile(path).Contents);
        Assert.AreEqual(
            content,
            fileSystem.File.ReadAllBytes(path));
    }
    private void SaveFileSystem(MockFileSystem fileSystem)
    {
        IFormatter formatter = new BinaryFormatter();
        Stream stream = new FileStream(Path.GetTempPath() + FS_FILENAME, FileMode.Create, FileAccess.Write);
        formatter.Serialize(stream, fileSystem);
        stream.Close();
    }
    private IFileSystem LoadFileSystem()
    {
        IFormatter formatter = new BinaryFormatter();
        Stream stream = new FileStream(Path.GetTempPath() + FS_FILENAME, FileMode.Open, FileAccess.Read);
        IFileSystem fileSystem = (MockFileSystem)formatter.Deserialize(stream);
        stream.Close();
        return fileSystem;
    }
    private void ClearFileSystem()
    {
        string temp = Path.GetTempPath() + FS_FILENAME;
        if (File.Exists(temp))
            File.Delete(temp);
    }
}

}

[darl2ng]

Thanks for the report! Would be more actionable if you'd include the callstack for the exception.

You're welcome. I've put a test unit that you can use to reproduce the bug, which shows: fileSystem.GetFile(path).Contents works ok but not fileSystem.File.ReadAllBytes(path));

Best,

[darl2ng]

My investigation leads to MockFileSystem's PathVerifier pathVerifier is not serializable so it's empty when deserialize and raise exception. A quick fix would be marking PathVerifier as serializable and remove UnSerialized PathVerifier pathVerifier in MockFileSystem.