Add broken test

Author: moffatman

testing/dart/plugin_utilities_test.dart

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:isolate';
 import 'dart:ui';
 
 import 'package:litetest/litetest.dart';
@@ -19,6 +20,34 @@ class Foo {
 
 const Foo foo = Foo();
 
+@pragma('vm:entry-point')
+Future<void> included() async {
+
+}
+
+Future<void> excluded() async {
+
+}
+
+@pragma('vm:entry-point')
+Future<void> runCallback(IsolateParam param) async {
+  try {
+    final Future<dynamic> Function() func = PluginUtilities.getCallbackFromHandle(CallbackHandle.fromRawHandle(param.rawHandle))! as Future<dynamic> Function();
+    await func.call();
+    param.sendPort.send(true);
+  }
+  catch (e) {
+    print(e);
+    param.sendPort.send(false);
+  }
+}
+
+class IsolateParam {
+  const IsolateParam(this.sendPort, this.rawHandle);
+  final SendPort sendPort;
+  final int rawHandle;
+}
+
 void main() {
   test('PluginUtilities Callback Handles', () {
     // Top level callback.
@@ -43,4 +72,15 @@ void main() {
     final Function anon = (int a, int b) => a + b; // ignore: prefer_function_declarations_over_variables
     expect(PluginUtilities.getCallbackHandle(anon), isNull);
   });
+
+  test('PluginUtilities Callback Handles in Isolate', () async {
+    ReceivePort port = ReceivePort();
+    await Isolate.spawn(runCallback, IsolateParam(port.sendPort, PluginUtilities.getCallbackHandle(included)!.toRawHandle()));
+    expect(await port.first, true);
+    port.close();
+    port = ReceivePort();
+    await Isolate.spawn(runCallback, IsolateParam(port.sendPort, PluginUtilities.getCallbackHandle(excluded)!.toRawHandle()));
+    expect(await port.first, false);
+    port.close();
+  });
 }