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internal/adapters/storage/fake.go

@@ -2,6 +2,8 @@ package storage
 
 import (
 	"context"
+	"crypto/sha256"
+	"encoding/hex"
 	"fmt"
 	"io"
 	"os"
@@ -21,6 +23,7 @@ type FakeBackend struct {
 	DownloadErr error
 	UploadErr   error
 	ExistsErr   error
+	UploadHook  func(FakeUploadCall) error
 }
 
 // FakeUploadCall captures one upload invocation in call order.
@@ -54,6 +57,9 @@ func (f *FakeBackend) SeedObject(obj FakeObject) {
 	obj.Key = key
 	obj.Data = append([]byte(nil), obj.Data...)
 	obj.Metadata = copyMetadata(obj.Metadata)
+	if obj.ETag == "" {
+		obj.ETag = fakeObjectETag(obj.Data)
+	}
 	f.Objects[key] = obj
 }
 
@@ -175,14 +181,20 @@ func (f *FakeBackend) uploadReader(ctx context.Context, source io.Reader, key st
 	}
 
 	normalizedKey := normalizeObjectKey(key)
-	f.Uploads = append(f.Uploads, FakeUploadCall{
+	call := FakeUploadCall{
 		LocalPath: localPath,
 		Key:       normalizedKey,
 		Options: UploadOptions{
 			Metadata:    copyMetadata(opts.Metadata),
 			ContentType: opts.ContentType,
 		},
-	})
+	}
+	f.Uploads = append(f.Uploads, call)
+	if f.UploadHook != nil {
+		if err := f.UploadHook(call); err != nil {
+			return ObjectInfo{}, err
+		}
+	}
 	now := time.Now().UTC()
 	obj := FakeObject{
 		Key:          normalizedKey,
@@ -194,10 +206,16 @@ func (f *FakeBackend) uploadReader(ctx context.Context, source io.Reader, key st
 	return ObjectInfo{
 		Key:          normalizedKey,
 		Size:         int64(len(data)),
+		ETag:         fakeObjectETag(data),
 		LastModified: &now,
 	}, nil
 }
 
+func fakeObjectETag(data []byte) string {
+	sum := sha256.Sum256(data)
+	return hex.EncodeToString(sum[:])
+}
+
 // Exists checks object presence.
 func (f *FakeBackend) Exists(ctx context.Context, key string) (bool, error) {
 	if err := ctx.Err(); err != nil {