chore: address PR feedback

Author: reubeno

internal/projectconfig/image.go

@@ -30,7 +30,6 @@ type ImageConfig struct {
 
 	// Capabilities describes the runtime capabilities of this image.
 	Capabilities ImageCapabilities `toml:"capabilities,omitempty" json:"capabilities,omitempty" jsonschema:"title=Capabilities,description=Runtime capabilities of this image"`
-
 }
 
 // ImagePublishConfig holds publishing settings for an image.
@@ -59,7 +58,7 @@ const (
 // about supported deployment and runtime scenarios.
 type ImageCapabilities struct {
 	// SupportedHosts lists the host types on which this image can be deployed or run.
-	SupportedHosts []SupportedHost `toml:"supported-hosts,omitempty" json:"supportedHosts,omitempty" jsonschema:"title=Supported hosts,description=Host types on which this image can be deployed or run,enum=azure-vm-gen1,enum=azure-vm-gen2,enum=oci-container"`
+	SupportedHosts []SupportedHost `toml:"supported-hosts,omitempty" json:"supportedHosts,omitempty" validate:"unique,dive,oneof=azure-vm-gen1 azure-vm-gen2 oci-container" jsonschema:"title=Supported hosts,description=Host types on which this image can be deployed or run,enum=azure-vm-gen1,enum=azure-vm-gen2,enum=oci-container"`
 
 	// RuntimePackageManagement indicates the image supports runtime package management
 	// (e.g., installing or removing packages after first boot).

internal/projectconfig/image_test.go

@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+package projectconfig_test
+
+import (
+	"testing"
+
+	"github.com/go-playground/validator/v10"
+	"github.com/microsoft/azure-linux-dev-tools/internal/projectconfig"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestImageCapabilities_SupportedHosts_Validation(t *testing.T) {
+	t.Run("empty is valid", func(t *testing.T) {
+		caps := projectconfig.ImageCapabilities{}
+		require.NoError(t, validator.New().Struct(&caps))
+	})
+
+	t.Run("single valid host", func(t *testing.T) {
+		caps := projectconfig.ImageCapabilities{
+			SupportedHosts: []projectconfig.SupportedHost{
+				projectconfig.SupportedHostAzureVMGen2,
+			},
+		}
+		require.NoError(t, validator.New().Struct(&caps))
+	})
+
+	t.Run("all valid hosts", func(t *testing.T) {
+		caps := projectconfig.ImageCapabilities{
+			SupportedHosts: []projectconfig.SupportedHost{
+				projectconfig.SupportedHostAzureVMGen1,
+				projectconfig.SupportedHostAzureVMGen2,
+				projectconfig.SupportedHostOCIContainer,
+			},
+		}
+		require.NoError(t, validator.New().Struct(&caps))
+	})
+
+	t.Run("invalid host is rejected", func(t *testing.T) {
+		caps := projectconfig.ImageCapabilities{
+			SupportedHosts: []projectconfig.SupportedHost{"hyperv"},
+		}
+		err := validator.New().Struct(&caps)
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "oneof")
+	})
+
+	t.Run("duplicate hosts are rejected", func(t *testing.T) {
+		caps := projectconfig.ImageCapabilities{
+			SupportedHosts: []projectconfig.SupportedHost{
+				projectconfig.SupportedHostAzureVMGen1,
+				projectconfig.SupportedHostAzureVMGen1,
+			},
+		}
+		err := validator.New().Struct(&caps)
+		require.Error(t, err)
+		assert.Contains(t, err.Error(), "unique")
+	})
+}