Assert the result stream is positioned at the start in SkiaSharp tests

Existing tests only checked Result.Length which doesn't depend on
Position, so a contributor that forgot to seek the result stream back
to 0 would still pass. Add an explicit Position == 0 assertion plus a
CopyToAsync round-trip that compares the copied length against the
result stream length, so the same regression cannot slip in again.

framework/test/Volo.Abp.Imaging.SkiaSharp.Tests/Volo/Abp/Imaging/SkiaSharpImageCompressorTests.cs

@@ -93,6 +93,23 @@ public class SkiaSharpImageCompressorTests : AbpImagingSkiaSharpTestBase
         compressedImage1.Result.Dispose();
     }
 
+    [Fact]
+    public async Task Should_Return_Compressed_Stream_Positioned_At_Start()
+    {
+        await using var jpegImage = ImageFileHelper.GetJpgTestFileStream();
+        var compressedImage = await ImageCompressor.CompressAsync(jpegImage);
+
+        compressedImage.ShouldNotBeNull();
+        compressedImage.State.ShouldBe(ImageProcessState.Done);
+        compressedImage.Result.Position.ShouldBe(0);
+
+        using var copy = new MemoryStream();
+        await compressedImage.Result.CopyToAsync(copy);
+        copy.Length.ShouldBe(compressedImage.Result.Length);
+
+        compressedImage.Result.Dispose();
+    }
+
     [Fact]
     public async Task Should_Return_Unsupported_For_Gif_Stream()
     {

framework/test/Volo.Abp.Imaging.SkiaSharp.Tests/Volo/Abp/Imaging/SkiaSharpImageResizerTests.cs

@@ -73,6 +73,23 @@ public class SkiaSharpImageResizerTests : AbpImagingSkiaSharpTestBase
         resizedImage1.Result.Dispose();
     }
 
+    [Fact]
+    public async Task Should_Return_Resized_Stream_Positioned_At_Start()
+    {
+        await using var jpegImage = ImageFileHelper.GetJpgTestFileStream();
+        var resizedImage = await ImageResizer.ResizeAsync(jpegImage, new ImageResizeArgs(100, 100));
+
+        resizedImage.ShouldNotBeNull();
+        resizedImage.State.ShouldBe(ImageProcessState.Done);
+        resizedImage.Result.Position.ShouldBe(0);
+
+        using var copy = new MemoryStream();
+        await resizedImage.Result.CopyToAsync(copy);
+        copy.Length.ShouldBe(resizedImage.Result.Length);
+
+        resizedImage.Result.Dispose();
+    }
+
     [Fact]
     public async Task Should_Return_Unsupported_For_Gif_Stream()
     {