test: add url launcher test

frontend/app_flowy/packages/appflowy_editor/test/extensions/url_launcher_extension_test.dart

@@ -0,0 +1,22 @@
+import 'package:appflowy_editor/src/extensions/url_launcher_extension.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  // test('safeLaunchUrl with scheme', () async {
+  //   const href = 'https://github.com/AppFlowy-IO';
+  //   final result = await safeLaunchUrl(href);
+  //   expect(result, true);
+  // });
+
+  // test('safeLaunchUrl without scheme', () async {
+  //   const href = 'github.com/AppFlowy-IO';
+  //   final result = await safeLaunchUrl(href);
+  //   expect(result, true);
+  // });
+
+  test('safeLaunchUrl without scheme', () async {
+    const href = null;
+    final result = await safeLaunchUrl(href);
+    expect(result, false);
+  });
+}