Fix onPlatform when used on a group(). (#613)

Closes #578

CHANGELOG.md

@@ -3,6 +3,8 @@
 * `throwsA()` and all related matchers will now match functions that return
   `Future`s that emit exceptions.
 
+* Respect `onPlatform` for groups.
+
 ## 0.12.20+13
 
 * Upgrade to package:matcher 0.12.1

lib/test.dart

@@ -196,7 +196,11 @@ void group(description, body(),
     tags,
     Map<String, dynamic> onPlatform}) {
   _declarer.group(description.toString(), body,
-      testOn: testOn, timeout: timeout, skip: skip, tags: tags);
+      testOn: testOn,
+      timeout: timeout,
+      skip: skip,
+      tags: tags,
+      onPlatform: onPlatform);
 
   // Force dart2js not to inline this function. We need it to be separate from
   // `main()` in JS stack traces in order to properly determine the line and

test/runner/runner_test.dart

@@ -562,6 +562,30 @@ void main() {
       test.stdout.expect(consumeThrough(contains("Skip: fifth")));
       test.shouldExit(0);
     });
+
+    test("applies platforms to a group", () {
+      d
+          .file(
+              "test.dart",
+              '''
+import 'dart:async';
+
+import 'package:test/test.dart';
+
+void main() {
+  group("group", () {
+    test("success", () {});
+  }, onPlatform: {
+    "vm": new Skip()
+  });
+}
+''')
+          .create();
+
+      var test = runTest(["test.dart"]);
+      test.stdout.expect(consumeThrough(contains("All tests skipped.")));
+      test.shouldExit(0);
+    });
   });
 
   group("with an @OnPlatform annotation", () {