Fix all strong-mode errors and warnings.

lib/src/runner.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.
 
 import 'dart:async';
 import 'dart:io';
 
 import 'package:async/async.dart';
 
 import 'backend/group.dart';
@@ skipping 214 matching lines @@
     ]);
     if (timer != null) timer.cancel();
     await _loader.close();
   });
 
   /// Return a stream of [LoadSuite]s in [_config.paths].
   ///
   /// Only tests that match [_config.patterns] will be included in the
   /// suites once they're loaded.
   Stream<LoadSuite> _loadSuites() {
-    return mergeStreams(_config.paths.map((path) {
+    return StreamGroup.merge(_config.paths.map((path) {
       if (new Directory(path).existsSync()) return _loader.loadDir(path);
       if (new File(path).existsSync()) return _loader.loadFile(path);
 
       return new Stream.fromIterable([
         new LoadSuite.forLoadException(
             new LoadException(path, 'Does not exist.'))
       ]);
     })).map((loadSuite) {
       return loadSuite.changeSuite((suite) {
         _warnForUnknownTags(suite);
 
         return _shardSuite(suite.filter((test) {
           // Skip any tests that don't match all the given patterns.
-          if (!_config.patterns.every(test.name.contains)) {
+          if (!_config.patterns
+              .every((pattern) => test.name.contains(pattern))) {
             return false;
           }
 
           // If the user provided tags, skip tests that don't match all of them.
           if (!_config.includeTags.evaluate(test.metadata.tags)) return false;
 
           // Skip tests that do match any tags the user wants to exclude.
           if (_config.excludeTags.evaluate(test.metadata.tags)) return false;
 
           return true;
@@ skipping 38 matching lines @@
     });
 
     print(buffer.toString());
   }
 
   /// Collects all tags used by [suite] or its children that aren't also passed
   /// on the command line.
   ///
   /// This returns a map from tag names to lists of entries that use those tags.
   Map<String, List<GroupEntry>> _collectUnknownTags(Suite suite) {
-    var unknownTags = {};
-    var currentTags = new Set();
+    var unknownTags = <String, List<GroupEntry>>{};
+    var currentTags = new Set<String>();
 
     collect(entry) {
-      var newTags = new Set();
+      var newTags = new Set<String>();
       for (var unknownTag in
           entry.metadata.tags.difference(_config.knownTags)) {
         if (currentTags.contains(unknownTag)) continue;
         unknownTags.putIfAbsent(unknownTag, () => []).add(entry);
         newTags.add(unknownTag);
       }
 
       if (entry is! Group) return;
 
       currentTags.addAll(newTags);
@@ skipping 50 matching lines @@
       await _debugOperation.valueOrCancellation();
     }).listen(null);
 
     var results = await Future.wait([
       _suiteSubscription.asFuture().then((_) => _engine.suiteSink.close()),
       _engine.run()
     ]);
     return results.last;
   }
 }