Add Mustang conformance test runner

Source/QuestPDF.ConformanceTests/QuestPDF.ConformanceTests.csproj

@@ -34,8 +34,5 @@
         <None Include="Resources\**\*.*">
             <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
         </None>
-        <None Update="Resources\photo.jpg">
-          <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
-        </None>
     </ItemGroup>
 </Project>

Source/QuestPDF.ConformanceTests/TestEngine/MustangConformanceTestRunner.cs

@@ -0,0 +1,80 @@
+using System.Diagnostics;
+using System.Text;
+using System.Xml.Linq;
+using QuestPDF.Fluent;
+using QuestPDF.Infrastructure;
+
+namespace QuestPDF.ConformanceTests.TestEngine;
+
+public static class MustangConformanceTestRunner
+{
+    public class ValidationResult
+    {
+        public bool IsDocumentValid => !FailedRules.Any();
+        public ICollection<string> FailedRules { get; set; } = [];
+        
+        public string GetErrorMessage()
+        {
+            var errorMessage = new StringBuilder();
+
+            foreach (var failedRule in FailedRules)
+            {
+                errorMessage.AppendLine($"🟥\tError");
+                errorMessage.AppendLine($"\t{failedRule}");
+                errorMessage.AppendLine();
+            }
+
+            return errorMessage.ToString();
+        }
+    }
+
+    public static void TestConformance(string filePath)
+    {
+        var result = RunMustang(filePath);
+
+        if (!result.IsDocumentValid)
+        {
+            Console.WriteLine(result.GetErrorMessage());
+            Assert.Fail();
+        }
+    }
+
+    private static ValidationResult RunMustang(string pdfFilePath)
+    {
+        if (!File.Exists(pdfFilePath))
+            throw new FileNotFoundException($"PDF file not found: {pdfFilePath}");
+
+        var mustangExecutablePath = Environment.GetEnvironmentVariable("MUSTANG_EXECUTABLE_PATH");
+        
+        if (string.IsNullOrEmpty(mustangExecutablePath))
+            throw new Exception("The location path of the Mustang executable is not set. Set the MUSTANG_EXECUTABLE_PATH environment variable to the path of the Mustang executable.");
+        
+        var arguments = $"-jar {mustangExecutablePath} --action validate --source {pdfFilePath}";
+
+        var process = new Process
+        {
+            StartInfo = new ProcessStartInfo
+            {
+                FileName = "java",
+                Arguments = arguments,
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
+                UseShellExecute = false,
+                CreateNoWindow = true
+            }
+        };
+
+        process.Start();
+        var output = process.StandardOutput.ReadToEnd();
+        process.WaitForExit();
+
+        return new ValidationResult()
+        {
+            FailedRules = XDocument
+                .Parse(output)
+                .Descendants("error")
+                .Select(x => x.Value)
+                .ToList()
+        };
+    }
+}