The backend S3 client now resolves credentials from user-configurable environment variables

internal/adapters/storage/s3_backend_test.go

@@ -187,6 +187,8 @@ func TestS3BackendExistsNotFound(t *testing.T) {
 func TestNewS3BackendFromConfigUsesClientOptions(t *testing.T) {
 	original := newS3Client
 	t.Cleanup(func() { newS3Client = original })
+	t.Setenv("OBJECT_STORAGE_KEY_ID", "id-123")
+	t.Setenv("OBJECT_STORAGE_KEY", "secret-abc")
 
 	var got s3ClientOptions
 	newS3Client = func(_ context.Context, opts s3ClientOptions) (s3API, error) {
@@ -209,6 +211,9 @@ func TestNewS3BackendFromConfigUsesClientOptions(t *testing.T) {
 	if got.Region != "us-east-1" || got.Endpoint != "http://localhost:9000" || !got.ForcePathStyle {
 		t.Fatalf("client options = %#v, want region/endpoint/path-style values", got)
 	}
+	if got.AccessKeyID != "id-123" || got.SecretKey != "secret-abc" {
+		t.Fatalf("client options credentials = %#v, want env-resolved static credentials", got)
+	}
 }
 
 func TestNewS3BackendFromConfigRequiresBucket(t *testing.T) {
@@ -218,6 +223,30 @@ func TestNewS3BackendFromConfigRequiresBucket(t *testing.T) {
 	}
 }
 
+func TestNewS3BackendFromConfigFallsBackWhenCredentialEnvMissing(t *testing.T) {
+	original := newS3Client
+	t.Cleanup(func() { newS3Client = original })
+
+	var got s3ClientOptions
+	newS3Client = func(_ context.Context, opts s3ClientOptions) (s3API, error) {
+		got = opts
+		return &fakeS3API{}, nil
+	}
+
+	_, err := NewS3BackendFromConfig(context.Background(), config.StorageS3Config{
+		Bucket:         "my-archive",
+		Region:         "us-east-1",
+		AccessKeyIDEnv: "MISSING_ACCESS_KEY_ID",
+		SecretKeyEnv:   "MISSING_SECRET_KEY",
+	})
+	if err != nil {
+		t.Fatalf("NewS3BackendFromConfig() error = %v", err)
+	}
+	if got.AccessKeyID != "" || got.SecretKey != "" {
+		t.Fatalf("client options credentials = %#v, want empty fallback values", got)
+	}
+}
+
 func strPtr(v string) *string { return &v }
 func int64Ptr(v int64) *int64 { return &v }