Add option to skip pdf byte normalization

src/Directory.Build.props

@@ -2,7 +2,7 @@
 <Project>
   <PropertyGroup>
     <NoWarn>CS1591;CS0649;CA1416;NU1608;NU1109</NoWarn>
-    <Version>5.27.0</Version>
+    <Version>5.28.0</Version>
     <LangVersion>preview</LangVersion>
     <AssemblyVersion>1.0.0</AssemblyVersion>
     <PackageTags>Aspose, Verify</PackageTags>

src/Verify.Aspose/VerifyAsposeSettings.cs

@@ -1,4 +1,4 @@
-namespace VerifyTestsAspose;
+namespace VerifyTestsAspose;
 
 public static class VerifyAsposeSettings
 {
@@ -67,4 +67,36 @@ internal static PngDevice GetPdfPngDevice(this IReadOnlyDictionary<string, objec
         var func = (Func<Aspose.Pdf.Page, PngDevice>) value;
         return func(page);
     }
-}
+
+    /// <summary>
+    /// Snapshots the pdf bytes exactly as produced, skipping the normalization that neutralizes the
+    /// trailer <c>/ID</c>, the <c>/CreationDate</c> and <c>/ModDate</c>, and the XMP dates and
+    /// identifiers. Use it when the producer already emits byte-deterministic documents, since
+    /// normalizing them again copies the whole buffer, rescans it, and — when the XMP packet is
+    /// canonicalized — rebuilds it and repairs the cross-reference table, all to change nothing.
+    /// </summary>
+    /// <remarks>
+    /// Only skip this when the producer is genuinely deterministic. Without it a freshly generated
+    /// pdf carries a wall-clock <c>/CreationDate</c> and a fresh <c>/ID</c>, so the snapshot differs
+    /// on every run.
+    /// <para>
+    /// The XMP canonicalization is worth calling out because it is the pass that changes bytes for
+    /// an already-deterministic producer: it collapses the packet's whitespace, so enabling or
+    /// disabling this setting on an existing suite shifts the stored <c>.verified.pdf</c> even
+    /// though nothing about the document changed. Expect to re-accept those snapshots once.
+    /// </para>
+    /// </remarks>
+    public static void SkipPdfNormalization(this VerifySettings settings) =>
+        settings.Context["VerifyAsposeSkipPdfNormalization"] = true;
+
+    /// <inheritdoc cref="SkipPdfNormalization(VerifySettings)"/>
+    public static SettingsTask SkipPdfNormalization(this SettingsTask settings)
+    {
+        settings.CurrentSettings.SkipPdfNormalization();
+        return settings;
+    }
+
+    internal static bool NormalizePdf(this IReadOnlyDictionary<string, object> settings) =>
+        !settings.TryGetValue("VerifyAsposeSkipPdfNormalization", out var value) ||
+        value is not true;
+}

src/Verify.Aspose/VerifyAspose_Pdf.cs

@@ -134,7 +134,7 @@ static ConversionResult ConvertPdf(string? name, Document document, IReadOnlyDic
         // Building the deterministic pdf is expensive, so skip it when the pdf target is excluded.
         if (!settings.IsTargetExcluded("pdf"))
         {
-            targets.Add(BuildPdfTarget(document));
+            targets.Add(BuildPdfTarget(document, settings.NormalizePdf()));
         }
 
         targets.AddRange(GetPdfStreams(name, document, settings));
@@ -145,11 +145,12 @@ static ConversionResult ConvertPdf(string? name, Document document, IReadOnlyDic
     // The pdf snapshot is always the full document, regardless of PagesToInclude: PagesToInclude
     // only trims the rendered png pages in GetPdfStreams. Mirrors BuildXlsxTarget/BuildDocxTarget,
     // which do the same for the OOXML formats via DeterministicPackage.
-    static Target BuildPdfTarget(Document document)
+    static Target BuildPdfTarget(Document document, bool normalize)
     {
         using var source = new MemoryStream();
         document.Save(source);
-        var resultStream = PdfNormalizer.Normalize(source);
+        source.Position = 0;
+        var resultStream = normalize ? PdfNormalizer.Normalize(source) : new MemoryStream(source.ToArray());
 
         return new("pdf", resultStream, performConversion: false)
         {