Fix test

pkgs/ffigen/test/config_tests/compiler_opts_test.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'dart:io';
+
 import 'package:ffigen/ffigen.dart';
 import 'package:ffigen/src/config_provider/spec_utils.dart';
 import 'package:ffigen/src/strings.dart' as strings;
@@ -40,7 +42,12 @@ ${strings.compilerOptsAuto}:
   ${strings.macos}:
     ${strings.includeCStdLib}: false
         ''');
-      expect(config.compilerOpts.isEmpty, true);
+      expect(
+        config.compilerOpts,
+        equals([
+          if (Platform.isMacOS) '-Wno-nullability-completeness',
+        ]),
+      );
     });
   });
 }