Combining VerifyDirectory with System.IO.Abstractions

[michael-wolfenden]

System.IO.Abstractions is an abstraction over System.IO that it extremely useful for testing IO. At the core of the library is IFileSystem. Instead of calling methods like File.ReadAllText directly you use IFileSystem.File.ReadAllText.

The idea is that there would be an overload (or some other method) that allows you to call VerifyDirectory with the existing parameters but also passing an IFileSystem. This would allow you to build an entire mock file system in memory and then call VerifyDirectory to verify it's contents.

For example:

[Fact]
public async Task UsingSystemIOAbstractions() {
    // MockFileSystem is provided by System.IO.Abstractions.TestingHelpers
    var fileSystem = new MockFileSystem(new Dictionary<string, MockFileData>
    {
        { @"c:\demo\jQuery.js", new MockFileData("some js") },
        { @"c:\demo\image.gif", new MockFileData(new byte[] { 0x12, 0x34, 0x56, 0xd2 }) },
        { @"c:\demo\subfolder\myfile.txt", new MockFileData("Testing is meh.") },
    });

    await VerifyDirectory(
        fileSystem,
        @"c:\demo",
        include: filePath => filePath.Contains("Doc"),
        pattern: "*.txt",
        options: new()
        {
            RecurseSubdirectories = false
        });
}

I imagine the implementation would be exactly the same as the existing implementation but replacing Directory.EnumerateFiles with IFileSystem.Directory.EnumerateFiles etc. I suppose VerifyFile could also be implemented as well.

I did attempt to implement myself however the existing implementation of VerifyDirectory relies heavily on a number of internal classes and methods.

[SimonCropp]

if i could make this (hypothetical) api work, would it suffice?

    var fileSystem = new MockFileSystem(new Dictionary<string, MockFileData>
    {
        { @"c:\demo\jQuery.js", new MockFileData("some js") },
        { @"c:\demo\image.gif", new MockFileData(new byte[] { 0x12, 0x34, 0x56, 0xd2 }) },
        { @"c:\demo\subfolder\myfile.txt", new MockFileData("Testing is meh.") },
    });

    var files = fileSystem.EnumerateFiles(
        @"c:\demo",
        "*.txt",
        SearchOption.AllDirectories);
    await Verify(files);

[michael-wolfenden]

I might be misunderstanding, but is your suggestion that Verify takes an enumerable of file paths?

If that's the case then it still wouldn't work as you need the IFileSystem to get the contents of the files via fileSystem.File.ReadAllText(..) for instance.

[SimonCropp]

i dont have capacity to add support System.IO.Abstractions. I am ahoy for you to create your own project that adds support