Fixing type check error using Stream.take in dart2js checked mode.

tests/html/history_test.dart

Index: tests/html/history_test.dart
diff --git a/tests/html/history_test.dart b/tests/html/history_test.dart
index bee3323b8866b1d7bc8748e877fb9b5fdea94e7c..87a6e83de61b4ae55c0aa8649749813967e6794a 100644
--- a/tests/html/history_test.dart
+++ b/tests/html/history_test.dart
@@ -3,16 +3,6 @@ import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_individual_config.dart';
 import 'dart:html';
 
-/// Waits for a callback once, then removes the event handler.
-void expectAsync1Once(EventListenerList list, void callback(arg)) {
-  var fn = null;
-  fn = expectAsync1((arg) {
-    list.remove(fn);
-    callback(arg);
-  });
-  list.add(fn);
-}
-
 main() {
   useHtmlIndividualConfiguration();
 
@@ -47,7 +37,7 @@ main() {
 
         // Need to wait a frame or two to let the pushState events occur.
         window.setTimeout(expectAsync0(() {
-          expectAsync1Once(window.on.popState, (_) {
+          window.onPopState.take(1).listen((_) {

[floitsch, 2013/01/24 17:17:18]

don't you need to wrap this function in an expectAsync1 ?

If you know that there is at least one, you could also use .first.then((_)...)
or even .single.then((_)...) if you know that there is exactly one.

             expect(window.history.length, length);
             expect(window.location.href.endsWith('dummy1'), isTrue);
           });