Question

Can I use ApprovalTests with PDF’s? I tried using the FileLauncher but it seems the identical PDF’s are slightly different at file (bit) level. Or did I use it wrongly?

[TestMethod]
[UseReporter(typeof(FileLauncherReporter))]
public void TestPdf()
{
    var createSomePdf = PdfCreate();

    ApprovalTests.Approvals.Verify(new FileInfo(createSomePdf.FileName));

}

Answer 1

The Pdf is most likely being created with a timestamp. Depending on the method used to create the pdf, you might be able to mock out the created time. but I had to scrub it.

Here’s the code I used to do that.

    public static void VerifyPdf(string coverFile)
    {
        ScrubPdf(coverFile);
        Approvals.Verify(new ExistingFileWriter(coverFile));
    }

    private static void ScrubPdf(string coverFile)
    {
        long location;
        using (var pdf = File.OpenRead(coverFile))
        {
            location = Find("/CreationDate (", pdf);

        }
        using (var pdf = File.OpenWrite(coverFile))
        {
            pdf.Seek(location, SeekOrigin.Begin);

            var original = "/CreationDate (D:20110426104115-07'00')";
            var desired = new System.Text.ASCIIEncoding().GetBytes(original);

            pdf.Write(desired, 0, desired.Length);
            pdf.Flush();
        }
    }