Support attaching existing Restic repositories

internal/service/repository_test.go

@@ -0,0 +1,41 @@
+package service
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestValidateExistingRepositoryPathAcceptsRepositoryRoot(t *testing.T) {
+	root := t.TempDir()
+	if err := os.WriteFile(filepath.Join(root, "config"), []byte("restic"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	if err := validateExistingRepositoryPath(root); err != nil {
+		t.Fatalf("repository root rejected: %v", err)
+	}
+}
+
+func TestValidateExistingRepositoryPathSuggestsDirectChild(t *testing.T) {
+	root := t.TempDir()
+	repository := filepath.Join(root, "server-backup")
+	if err := os.Mkdir(repository, 0700); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(repository, "config"), []byte("restic"), 0600); err != nil {
+		t.Fatal(err)
+	}
+	err := validateExistingRepositoryPath(root)
+	if err == nil || !strings.Contains(err.Error(), repository) {
+		t.Fatalf("missing repository suggestion: %v", err)
+	}
+}
+
+func TestValidateExistingRepositoryPathExplainsMissingConfig(t *testing.T) {
+	root := t.TempDir()
+	err := validateExistingRepositoryPath(root)
+	if err == nil || !strings.Contains(err.Error(), "config, data, index, keys und snapshots") {
+		t.Fatalf("missing layout guidance: %v", err)
+	}
+}