Add tests for topleft origin

tests/ImageSharp.Tests/Formats/Tga/TgaDecoderTests.cs

@@ -91,6 +91,30 @@ namespace SixLabors.ImageSharp.Tests.Formats.Tga
             }
         }
 
+        [Theory]
+        [WithFile(Bit24RleTopLeft, PixelTypes.Rgba32)]
+        public void TgaDecoder_CanDecode_RunLengthEncoded_WithTopLeftOrigin_24Bit<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            using (Image<TPixel> image = provider.GetImage(new TgaDecoder()))
+            {
+                image.DebugSave(provider);
+                CompareWithReferenceDecoder(provider, image);
+            }
+        }
+
+        [Theory]
+        [WithFile(Bit24TopLeft, PixelTypes.Rgba32)]
+        public void TgaDecoder_CanDecode_Uncompressed_WithTopLeftOrigin_24Bit<TPixel>(TestImageProvider<TPixel> provider)
+            where TPixel : struct, IPixel<TPixel>
+        {
+            using (Image<TPixel> image = provider.GetImage(new TgaDecoder()))
+            {
+                image.DebugSave(provider);
+                CompareWithReferenceDecoder(provider, image);
+            }
+        }
+
         [Theory]
         [WithFile(Bit32, PixelTypes.Rgba32)]
         public void TgaDecoder_CanDecode_Uncompressed_32Bit<TPixel>(TestImageProvider<TPixel> provider)

tests/ImageSharp.Tests/TestImages.cs

@@ -373,6 +373,8 @@ namespace SixLabors.ImageSharp.Tests
             public const string Bit16 = "Tga/targa_16bit.tga";
             public const string Bit16PalRle = "Tga/ccm8.tga";
             public const string Bit24 = "Tga/targa_24bit.tga";
+            public const string Bit24TopLeft = "Tga/targa_24bit_origin_topleft.tga";
+            public const string Bit24RleTopLeft = "Tga/targa_24bit_rle_origin_topleft.tga";
             public const string Bit32 = "Tga/targa_32bit.tga";
             public const string Grey = "Tga/targa_8bit.tga";
             public const string GreyRle = "Tga/targa_8bit_rle.tga";