Fix tests for VM in checked mode.

pkg/oauth2/test/client_test.dart

 // Copyright (c) 2012, 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 client_test;
 
+import 'dart:async';
 import 'dart:io';
-import 'dart:json';
+import 'dart:json' as JSON;
 import 'dart:uri';
 
 import '../../unittest/lib/unittest.dart';
 import '../../http/lib/http.dart' as http;
 import '../lib/oauth2.dart' as oauth2;
 import 'utils.dart';
 
 final Uri requestUri = new Uri.fromString("http://example.com/resource");
 
 final Uri tokenEndpoint = new Uri.fromString('http://example.com/token');
 
 ExpectClient httpClient;
 
 void createHttpClient() {
   httpClient = new ExpectClient();
 }
 
+void expectFutureThrows(future, predicate) {
+  future.catchError(expectAsync1((AsyncError e) {
+    expect(predicate(e.error), isTrue);
+  }));
+}
+
 void main() {
   group('with expired credentials', () {
     setUp(createHttpClient);
 
     test("that can't be refreshed throws an ExpirationException on send", () {
       var expiration = new Date.now().subtract(new Duration(hours: 1));
       var credentials = new oauth2.Credentials(
           'access token', null, null, [], expiration);
       var client = new oauth2.Client('identifier', 'secret', credentials,
           httpClient: httpClient);
 
-      expect(client.get(requestUri), throwsExpirationException);
+      expectFutureThrows(client.get(requestUri),
+                         (e) => e is oauth2.ExpirationException);
     });
 
     test("that can be refreshed refreshes the credentials and sends the "
         "request", () {
       var expiration = new Date.now().subtract(new Duration(hours: 1));
       var credentials = new oauth2.Credentials(
           'access token', 'refresh token', tokenEndpoint, [], expiration);
       var client = new oauth2.Client('identifier', 'secret', credentials,
           httpClient: httpClient);
 
@@ skipping 59 matching lines @@
       expect(client.refreshCredentials().then((_) {
         expect(client.credentials.accessToken, equals('new access token'));
       }), completes);
     });
 
     test("without a refresh token can't manually refresh the credentials", () {
       var credentials = new oauth2.Credentials('access token');
       var client = new oauth2.Client('identifier', 'secret', credentials,
           httpClient: httpClient);
 
-      expect(client.refreshCredentials(), throwsStateError);
+      expectFutureThrows(client.refreshCredentials(),
+                         (e) => e is StateError);
     });
   });
 
   group('with invalid credentials', () {
     setUp(createHttpClient);
 
     test('throws an AuthorizationException for a 401 response', () {
       var credentials = new oauth2.Credentials('access token');
       var client = new oauth2.Client('identifier', 'secret', credentials,
           httpClient: httpClient);
 
       httpClient.expectRequest((request) {
         expect(request.method, equals('GET'));
         expect(request.url.toString(), equals(requestUri.toString()));
         expect(request.headers['authorization'],
             equals('Bearer access token'));
 
         var authenticate = 'Bearer error="invalid_token", error_description='
             '"Something is terribly wrong."';
         return new Future.immediate(new http.Response('bad job', 401,
                 headers: {'www-authenticate': authenticate}));
       });
 
-      expect(client.read(requestUri), throwsAuthorizationException);
+      expectFutureThrows(client.read(requestUri),
+                         (e) => e is oauth2.AuthorizationException);
     });
 
     test('passes through a 401 response without www-authenticate', () {
       var credentials = new oauth2.Credentials('access token');
       var client = new oauth2.Client('identifier', 'secret', credentials,
           httpClient: httpClient);
 
       httpClient.expectRequest((request) {
         expect(request.method, equals('GET'));
         expect(request.url.toString(), equals(requestUri.toString()));
@@ skipping 64 matching lines @@
         return new Future.immediate(new http.Response('bad job', 401,
                 headers: {'www-authenticate': 'Bearer'}));
       });
 
       expect(
           client.get(requestUri).then((response) => response.statusCode),
           completion(equals(401)));
     });
   });
 }