ensure dart defines work on web and not web (#51505)
diff --git a/packages/flutter/test/foundation/defines_test.dart b/packages/flutter/test/foundation/defines_test.dart
new file mode 100644
index 0000000..daf5835
--- /dev/null
+++ b/packages/flutter/test/foundation/defines_test.dart
@@ -0,0 +1,14 @@
+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+ test('defines match expectations per platform', () {
+ expect(kIsWeb, !const bool.fromEnvironment('dart.library.io'));
+ expect(kIsWeb, !const bool.fromEnvironment('dart.library.isolate'));
+ expect(kIsWeb, const bool.fromEnvironment('dart.library.html'));
+ });
+}
