test: add test cases for storage key

Author: mcquenji

test/shared/tests/storage_key_test.dart

@@ -0,0 +1,26 @@
+import 'package:grumpy/grumpy.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('StorageKey', () {
+    test('.asStorageKey() is reversible', () {
+      final key = const StorageKey(
+        namespace: 'test',
+        primaryKey: 'asStorageKey()',
+        schemaId: 'reversible',
+      );
+
+      final storageKey = key.asStorageKey();
+      final reversedKey = StorageKey.parse(storageKey);
+      expect(reversedKey, key);
+      expect(storageKey, key.asStorageKey());
+    });
+
+    test('parse throws on invalid format', () {
+      expect(
+        () => StorageKey.parse('invalid-format'),
+        throwsA(isA<FormatException>()),
+      );
+    });
+  });
+}