Detect an expired content shell and emit a nice error.

lib/src/runner/browser/server.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // 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.
 
 library test.runner.browser.server;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
@@ skipping 232 matching lines @@
         return url.resolveUri(
             p.toUri(p.relative(path, from: _root) + ".browser_test.html"));
       });
     }).then((suiteUrl) {
       if (_closed) return null;
 
       // TODO(nweiz): Don't start the browser until all the suites are compiled.
       return _browserManagerFor(browser).then((browserManager) {
         if (_closed) return null;
         return browserManager.loadSuite(path, suiteUrl);
-      }).then((suite) => suite.change(platform: browser.name));
+      }).then((suite) {
+        if (_closed) return null;
+        if (suite != null) return suite.change(platform: browser.name);
+
+        // If the browser manager fails to load a suite and the server isn't
+        // closed, it's probably because the browser failed. We emit the failure
+        // here to ensure that it gets surfaced.
+        return _browsers[browser].onExit;
+      });
     });
   }
 
   /// Loads a test suite at [path] from the `pub serve` URL [jsUrl].
   ///
   /// This ensures that only one suite is loaded at a time, and that any errors
   /// are exposed as [LoadException]s.
   Future _pubServeSuite(String path, Uri jsUrl) {
     return _pubServePool.withResource(() {
       var timer = new Timer(new Duration(seconds: 1), () {
@@ skipping 116 matching lines @@
       if (_pubServeUrl == null) {
         new Directory(_compiledDir).deleteSync(recursive: true);
       } else {
         _http.close();
       }
 
       _closeCompleter.complete();
     }).catchError(_closeCompleter.completeError);
   }
 }