test: add coverage for LoadValidatedImage size limits

Author: jurczewski

tests/PrivatePdfConverter.Tests/IntegrationTests/Commands/DirToPdfIntegrationTests.cs

@@ -44,4 +44,35 @@ public void ConvertDirectoryToOnePdf_ShouldBehaveCorrectly()
         // Clean up
         Directory.Delete(inputDirPath, true);
     }
+
+    [Fact]
+    public void ConvertDirectoryToOnePdf_ShouldNotCreatePdf_WhenImageExceedsLimits()
+    {
+        // End-to-end smoke: dir command must not write a PDF when LoadValidatedImage rejects input.
+        var inputDirPath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N"));
+        const string outputFileName = "final.pdf";
+        var outputPath = Path.Combine(inputDirPath, outputFileName);
+        Directory.CreateDirectory(inputDirPath);
+
+        var oversizedImagePath = Path.Combine(inputDirPath, "oversized.png");
+
+        try
+        {
+            using (var image = new MagickImage(MagickColors.Red, 10_001, 100))
+            {
+                image.Write(oversizedImagePath);
+            }
+
+            DirToPdf.ConvertDirectoryToOnePdf(inputDirPath, outputFileName);
+
+            File.Exists(outputPath).Should().BeFalse();
+        }
+        finally
+        {
+            if (Directory.Exists(inputDirPath))
+            {
+                Directory.Delete(inputDirPath, true);
+            }
+        }
+    }
 }

tests/PrivatePdfConverter.Tests/IntegrationTests/Commands/ImgToPdfIntegrationTests.cs

@@ -30,4 +30,36 @@ public void ConvertImageToOnePdf_ShouldBehaveCorrectly()
         File.Delete(inputFilePath);
         File.Delete(outputPdfPath);
     }
+
+    [Fact]
+    public void ConvertImageToOnePdf_ShouldNotCreatePdf_WhenImageExceedsLimits()
+    {
+        // End-to-end smoke: command must not write a PDF when LoadValidatedImage rejects input.
+        var inputFilePath = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid():N}.png");
+        var expectedOutputPath = Path.ChangeExtension(inputFilePath, ".pdf");
+
+        try
+        {
+            using (var image = new MagickImage(MagickColors.Red, 10_001, 100))
+            {
+                image.Write(inputFilePath);
+            }
+
+            ImgToPdf.ConvertImageToOnePdf(inputFilePath, null);
+
+            File.Exists(expectedOutputPath).Should().BeFalse();
+        }
+        finally
+        {
+            if (File.Exists(inputFilePath))
+            {
+                File.Delete(inputFilePath);
+            }
+
+            if (File.Exists(expectedOutputPath))
+            {
+                File.Delete(expectedOutputPath);
+            }
+        }
+    }
 }

tests/PrivatePdfConverter.Tests/UnitTests/FileServiceUnitTests.cs

@@ -1,3 +1,4 @@
+using ImageMagick;
 using PrivatePdfConverter.Services;
 
 namespace PrivatePdfConverter.Tests.UnitTests;
@@ -83,4 +84,78 @@ public void PrepareOutputFileName_WithEmptyOutput_ShouldDeriveFromSourcePath()
         // Assert
         result.Should().Be("file.pdf");
     }
+
+    [Fact]
+    public void LoadValidatedImage_ShouldReturnImage_WhenWithinLimits()
+    {
+        var path = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid():N}.png");
+
+        try
+        {
+            using (var image = new MagickImage(MagickColors.Red, 100, 100))
+            {
+                image.Write(path);
+            }
+
+            using var result = FileService.LoadValidatedImage(path);
+
+            result.Should().NotBeNull();
+            result.Width.Should().Be(100);
+            result.Height.Should().Be(100);
+        }
+        finally
+        {
+            if (File.Exists(path))
+            {
+                File.Delete(path);
+            }
+        }
+    }
+
+    [Fact]
+    public void LoadValidatedImage_ShouldReturnNull_WhenWidthExceedsLimit()
+    {
+        var path = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid():N}.png");
+
+        try
+        {
+            using (var image = new MagickImage(MagickColors.Red, 10_001, 100))
+            {
+                image.Write(path);
+            }
+
+            FileService.LoadValidatedImage(path).Should().BeNull();
+        }
+        finally
+        {
+            if (File.Exists(path))
+            {
+                File.Delete(path);
+            }
+        }
+    }
+
+    [Fact]
+    public void LoadValidatedImage_ShouldReturnNull_WhenAreaExceedsLimit()
+    {
+        var path = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid():N}.png");
+
+        try
+        {
+            // Within per-side limits (10_000) but 5000 * 20_001 > 100_000_000 total area.
+            using (var image = new MagickImage(MagickColors.Red, 5000, 20_001))
+            {
+                image.Write(path);
+            }
+
+            FileService.LoadValidatedImage(path).Should().BeNull();
+        }
+        finally
+        {
+            if (File.Exists(path))
+            {
+                File.Delete(path);
+            }
+        }
+    }
 }