From a7122f3a2450a512323f526cace4f9a0001c2169 Mon Sep 17 00:00:00 2001
From: Eli Belash <elibelash@gmail.com>
Date: Sun, 8 Feb 2026 14:25:39 +0200
Subject: [PATCH] Skip Bitmap tests on non-Windows platforms

System.Drawing.Common requires GDI+ which is only available on Windows
since .NET 6. Add [ClassInitialize] with OperatingSystem.IsWindows()
check to all three Bitmap test classes so they report as Inconclusive
(skipped) on Linux/macOS CI runners instead of failing with
PlatformNotSupportedException.
---
 .../NumSharp.Bitmap/BitmapExtensionsTests.cs           |  7 +++++++
 .../NumSharp.Bitmap/BitmapWithAlphaTests.cs            | 10 +++++++++-
 test/NumSharp.UnitTest/OpenBugs.Bitmap.cs              |  7 +++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/test/NumSharp.UnitTest/NumSharp.Bitmap/BitmapExtensionsTests.cs b/test/NumSharp.UnitTest/NumSharp.Bitmap/BitmapExtensionsTests.cs
index ea92f70f4..25458b549 100644
--- a/test/NumSharp.UnitTest/NumSharp.Bitmap/BitmapExtensionsTests.cs
+++ b/test/NumSharp.UnitTest/NumSharp.Bitmap/BitmapExtensionsTests.cs
@@ -10,6 +10,13 @@ namespace NumSharp.UnitTest
     [TestClass]
     public class BitmapExtensionsTests : TestClass
     {
+        [ClassInitialize]
+        public static void RequireWindows(TestContext _)
+        {
+            if (!OperatingSystem.IsWindows())
+                Assert.Inconclusive("System.Drawing.Common requires Windows (GDI+).");
+        }
+
         // ================================================================
         // Bugs discovered during test coverage expansion:
         //
diff --git a/test/NumSharp.UnitTest/NumSharp.Bitmap/BitmapWithAlphaTests.cs b/test/NumSharp.UnitTest/NumSharp.Bitmap/BitmapWithAlphaTests.cs
index f95c2cd1e..689f9ec8e 100644
--- a/test/NumSharp.UnitTest/NumSharp.Bitmap/BitmapWithAlphaTests.cs
+++ b/test/NumSharp.UnitTest/NumSharp.Bitmap/BitmapWithAlphaTests.cs
@@ -1,4 +1,5 @@
-using System.Drawing.Imaging;
+using System;
+using System.Drawing.Imaging;
 using System.Resources;
 using FluentAssertions;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
@@ -9,6 +10,13 @@ namespace NumSharp.UnitTest
     [TestClass]
     public class BitmapWithAlphaTests : TestClass
     {
+        [ClassInitialize]
+        public static void RequireWindows(TestContext _)
+        {
+            if (!OperatingSystem.IsWindows())
+                Assert.Inconclusive("System.Drawing.Common requires Windows (GDI+).");
+        }
+
         [TestMethod]
         public void ToNDArray_Case1()
         {
diff --git a/test/NumSharp.UnitTest/OpenBugs.Bitmap.cs b/test/NumSharp.UnitTest/OpenBugs.Bitmap.cs
index 227409656..0a5d25b6d 100644
--- a/test/NumSharp.UnitTest/OpenBugs.Bitmap.cs
+++ b/test/NumSharp.UnitTest/OpenBugs.Bitmap.cs
@@ -57,6 +57,13 @@ namespace NumSharp.UnitTest
     [TestClass]
     public class OpenBugsBitmap : TestClass
     {
+        [ClassInitialize]
+        public static void RequireWindows(TestContext _)
+        {
+            if (!OperatingSystem.IsWindows())
+                Assert.Inconclusive("System.Drawing.Common requires Windows (GDI+).");
+        }
+
         // ================================================================
         //
         //  BUG 1: ToNDArray(copy:true) on odd-width 24bpp images produces