Add tests for internal/storage: URL parsing, backends, shared conformance suite (closes #66)

internal/storage, the package that parses store URLs and selects the backend, had no tests.

Adds table-driven tests for URL parsing (each scheme, query parameters, malformed input, unknown scheme, backend type chosen); one shared conformance suite for the Storer interface, run against the file backend in a temp directory and the s3 backend on the in-process harness internal/s3 already uses, so a new backend inherits it; and rclone construction and argument tests using its in-process local backend. A comment records that rclone data operations need a configured remote and are not unit-tested. No production code changed and no defect surfaced.

model: claude-opus-4-8 (implementation, review); claude-fable-5-1 (merge)

internal/storage/url_parse_test.go

@@ -0,0 +1,110 @@
+package storage_test
+
+import (
+	"errors"
+	"reflect"
+	"testing"
+
+	"sneak.berlin/go/vaultik/internal/storage"
+)
+
+// TestParseStorageURLValid checks that each supported scheme parses into
+// the expected fields, since those fields decide which backend is built.
+func TestParseStorageURLValid(t *testing.T) {
+	t.Parallel()
+
+	const bucket = "mybucket"
+
+	cases := []struct {
+		name string
+		raw  string
+		want *storage.URL
+	}{
+		{
+			name: "file absolute path",
+			raw:  "file:///var/backups/vaultik",
+			want: &storage.URL{Scheme: "file", Prefix: "/var/backups/vaultik"},
+		},
+		{
+			name: "s3 bucket and prefix, ssl defaults on",
+			raw:  "s3://mybucket/backups/host",
+			want: &storage.URL{
+				Scheme: "s3", Bucket: bucket,
+				Prefix: "backups/host", UseSSL: true,
+			},
+		},
+		{
+			name: "s3 bucket only",
+			raw:  "s3://mybucket",
+			want: &storage.URL{Scheme: "s3", Bucket: bucket, UseSSL: true},
+		},
+		{
+			name: "s3 with endpoint, region, ssl off",
+			raw:  "s3://mybucket?endpoint=minio.example.com&region=us-west-2&ssl=false",
+			want: &storage.URL{
+				Scheme: "s3", Bucket: bucket,
+				Endpoint: "minio.example.com", Region: "us-west-2", UseSSL: false,
+			},
+		},
+		{
+			name: "rclone remote and path",
+			raw:  "rclone://gdrive/backups/host",
+			want: &storage.URL{
+				Scheme: "rclone", RcloneRemote: "gdrive", Prefix: "backups/host",
+			},
+		},
+		{
+			name: "rclone remote only",
+			raw:  "rclone://gdrive",
+			want: &storage.URL{Scheme: "rclone", RcloneRemote: "gdrive"},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			got, err := storage.ParseStorageURL(tc.raw)
+			if err != nil {
+				t.Fatalf("ParseStorageURL(%q) returned error: %v", tc.raw, err)
+			}
+
+			if !reflect.DeepEqual(got, tc.want) {
+				t.Errorf("ParseStorageURL(%q) = %+v, want %+v", tc.raw, got, tc.want)
+			}
+		})
+	}
+}
+
+// TestParseStorageURLErrors checks that empty, missing, and unknown-scheme
+// inputs fail with the documented sentinel errors instead of parsing to a
+// wrong destination.
+func TestParseStorageURLErrors(t *testing.T) {
+	t.Parallel()
+
+	cases := []struct {
+		name    string
+		raw     string
+		wantErr error
+	}{
+		{"empty url", "", storage.ErrEmptyStorageURL},
+		{"file empty path", "file://", storage.ErrEmptyFilePath},
+		{"s3 missing bucket", "s3://", storage.ErrMissingBucket},
+		{"s3 missing bucket with path", "s3:///justprefix", storage.ErrMissingBucket},
+		{"rclone missing remote", "rclone://", storage.ErrMissingRemote},
+		{"unknown scheme", "gs://bucket/x", storage.ErrUnsupportedScheme},
+		{"no scheme", "/local/path", storage.ErrUnsupportedScheme},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			_, err := storage.ParseStorageURL(tc.raw)
+			if !errors.Is(err, tc.wantErr) {
+				t.Errorf("ParseStorageURL(%q) error = %v, want %v",
+					tc.raw, err, tc.wantErr)
+			}
+		})
+	}
+}