converter.md

Converters

Converters are used to split a target into its component parts, then verify each of those parts.

When a target is split the result is:

• An info file (containing the metadata of the target) serialized as json. File name: {TestType}.{TestMethod}.info.verified.txt
• Zero or more documents of a specified extension. File name: {TestType}.{TestMethod}.{Index}.verified.{Extension}

Usage scenarios

• tiff => png per page
• spreadsheet => csv per sheet
• pdf => png per page

Example

Both the following examples take an input tiff and convert it to:

The info file:

{
  PixelFormat: Format8bppIndexed,
  Size: 473, 355
}

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Multiple png files:

Typed converter

This sample uses a typed approach. So the converter acts on an in memory instance matching based on type.

VerifierSettings.RegisterFileConverter<Image>(
    canConvert: (target, extension, context) => Equals(target.RawFormat, ImageFormat.Tiff),
    conversion: (image, settings) =>
    {
        var pages = image.GetFrameCount(FrameDimension.Page);

        var targets = new List<Target>();
        for (var index = 0; index < pages; index++)
        {
            image.SelectActiveFrame(FrameDimension.Page, index);

            var page = new MemoryStream();
            image.Save(page, ImageFormat.Png);
            targets.Add(new("png", page));
        }

        return new(
            info: new
            {
                image.PixelFormat,
                image.Size
            },
            targets);
    });

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using var stream = File.OpenRead("sample.tif");
await Verify(Image.FromStream(stream));

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Note that this sample also uses the optional canConvert to ensure that only Images that are tiffs are converted.

canConvert: (target, extension, context) => Equals(target.RawFormat, ImageFormat.Tiff),

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Expression converter

This sample uses a extension approach. So the converter acts on a file or stream based on the extension (configured or detected).

VerifierSettings.RegisterFileConverter(
    fromExtension: "tif",
    conversion: (stream, settings) =>
    {
        using var image = Image.FromStream(stream);
        var pages = image.GetFrameCount(FrameDimension.Page);

        var targets = new List<Target>();
        for (var index = 0; index < pages; index++)
        {
            image.SelectActiveFrame(FrameDimension.Page, index);

            var page = new MemoryStream();
            image.Save(page, ImageFormat.Png);
            targets.Add(new("png", page));
        }

        return new(
            info: new
            {
                image.PixelFormat,
                image.Size
            },
            targets);
    });

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await VerifyFile("sample.tif");

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Cleanup

If cleanup needs to occur after verification a callback can be passes to ConversionResult:

return new(
    info: info,
    "bin",
    stream: File.OpenRead(filePath),
    cleanup: () =>
    {
        File.Delete(filePath);
        return Task.CompletedTask;
    });

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Shipping

Converters can be shipped as NuGet packages:

• Verify.Aspose: Verification of documents (pdf, docx, xslx, and pptx) via Aspose.
• Verify.EntityFramework: Verification of EntityFramework bits.
• Verify.ImageMagick: Verification and comparison of images via Magick.NET.
• Verify.ImageSharp: Verification of images via ImageSharp.
• Verify.NServiceBus: Verify NServiceBus Test Contexts.
• Verify.RavenDb: Verification of RavenDb bits.
• Verify.SqlServer: Verification of SqlServer bits.
• Verify.Web: Verification of web bits.
• Verify.WinForms: Verification of WinForms UIs.
• Verify.Xaml: Verification of Xaml UIs.