add more ImageIndexGenertorTests

Author: Surayya Huseyn Zada

src/Containers/Microsoft.NET.Build.Containers/ImageIndexGenerator.cs

@@ -46,6 +46,11 @@ internal static (string, string) GenerateImageIndex(BuiltImage[] images)
 
     internal static string GenerateImageIndex(BuiltImage[] images, string manifestMediaType, string imageIndexMediaType)
     {
+        if (images.Length == 0)
+        {
+            throw new ArgumentException(string.Format(Strings.ImagesEmpty));
+        }
+        
         // Here we are using ManifestListV2 struct, but we could use ImageIndexV1 struct as well.
         // We are filling the same fields, so we can use the same struct.
         var manifests = new PlatformSpecificManifest[images.Length];

src/Tests/Microsoft.NET.Build.Containers.UnitTests/ImageIndexGeneratorTests.cs

@@ -15,6 +15,14 @@ public void ImagesCannotBeEmpty()
         Assert.Equal(Strings.ImagesEmpty, ex.Message);
     }
 
+    [Fact]
+    public void ImagesCannotBeEmpty_SpecifiedMediaType()
+    {
+        BuiltImage[] images = Array.Empty<BuiltImage>();
+        var ex = Assert.Throws<ArgumentException>(() => ImageIndexGenerator.GenerateImageIndex(images, "manifestMediaType", "imageIndexMediaType"));
+        Assert.Equal(Strings.ImagesEmpty, ex.Message);
+    }
+
     [Fact]
     public void UnsupportedMediaTypeThrows()
     {
@@ -133,4 +141,11 @@ public void GenerateOciImageIndex()
         Assert.Equal("{\"schemaVersion\":2,\"mediaType\":\"application/vnd.oci.image.index.v1\\u002Bjson\",\"manifests\":[{\"mediaType\":\"application/vnd.oci.image.manifest.v1\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest1\",\"platform\":{\"architecture\":\"arch1\",\"os\":\"os1\"}},{\"mediaType\":\"application/vnd.oci.image.manifest.v1\\u002Bjson\",\"size\":3,\"digest\":\"sha256:digest2\",\"platform\":{\"architecture\":\"arch2\",\"os\":\"os2\"}}]}", imageIndex);
         Assert.Equal(SchemaTypes.OciImageIndexV1, mediaType);
     }
+
+    [Fact]
+    public void GenerateImageIndexWithAnnotations()
+    {
+        string imageIndex = ImageIndexGenerator.GenerateImageIndexWithAnnotations("mediaType", "sha256:digest", 3, "repository", ["1.0", "2.0"]);
+        Assert.Equal("{\"schemaVersion\":2,\"mediaType\":\"application/vnd.oci.image.index.v1\\u002Bjson\",\"manifests\":[{\"mediaType\":\"mediaType\",\"size\":3,\"digest\":\"sha256:digest\",\"platform\":{},\"annotations\":{\"io.containerd.image.name\":\"repository:1.0\",\"org.opencontainers.image.ref.name\":\"1.0\"}},{\"mediaType\":\"mediaType\",\"size\":3,\"digest\":\"sha256:digest\",\"platform\":{},\"annotations\":{\"io.containerd.image.name\":\"repository:2.0\",\"org.opencontainers.image.ref.name\":\"2.0\"}}]}", imageIndex);
+    }
 }