feature: tag tests; choose tags on command line

lib/test.dart

 // Copyright (c) 2013, 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;
 
 import 'dart:async';
 
 import 'package:path/path.dart' as p;
 
 import 'src/backend/declarer.dart';
 import 'src/backend/test_platform.dart';
 import 'src/frontend/timeout.dart';
 import 'src/runner/engine.dart';
 import 'src/runner/reporter/expanded.dart';
 import 'src/runner/runner_suite.dart';
 import 'src/runner/vm/environment.dart';
 import 'src/utils.dart';
 
 export 'package:matcher/matcher.dart';
 
 export 'src/frontend/expect.dart';
 export 'src/frontend/expect_async.dart';
 export 'src/frontend/future_matchers.dart';
 export 'src/frontend/on_platform.dart';
 export 'src/frontend/prints_matcher.dart';
 export 'src/frontend/skip.dart';
+export 'src/frontend/tags.dart';
 export 'src/frontend/test_on.dart';
 export 'src/frontend/throws_matcher.dart';
 export 'src/frontend/throws_matchers.dart';
 export 'src/frontend/timeout.dart';
 
 /// The global declarer.
 ///
 /// This is used if a test file is run directly, rather than through the runner.
 Declarer _globalDeclarer;
 
@@ skipping 67 matching lines @@
 ///       "windows": new Timeout.factor(2),
 ///       "browser": [
 ///         new Skip("TODO: add browser support"),
 ///         // This will be slow on browsers once it works on them.
 ///         new Timeout.factor(2)
 ///       ]
 ///     });
 ///
 /// If multiple platforms match, the annotations apply in order as through
 /// they were in nested groups.
-void test(String description, body(), {String testOn, Timeout timeout,
-        skip, Map<String, dynamic> onPlatform, String tag,
-        List<String> tags}) => _declarer.test(description, body,
-            testOn: testOn, timeout: timeout, skip: skip,
-            onPlatform: onPlatform, tags: _deconvenienceTags(tag, tags));
+void test(String description, body(),
+        {String testOn,
+        Timeout timeout,
+        skip,
+        Map<String, dynamic> onPlatform,
+        tags}) =>
+    _declarer.test(description, body,
+        testOn: testOn,
+        timeout: timeout,
+        skip: skip,
+        onPlatform: onPlatform,
+        tags: tags);
 
 /// Creates a group of tests.
 ///
 /// A group's description is included in the descriptions of any tests or
 /// sub-groups it contains. [setUp] and [tearDown] are also scoped to the
 /// containing group.
 ///
 /// If [testOn] is passed, it's parsed as a [platform selector][]; the test will
 /// only be run on matching platforms.
 ///
@@ skipping 20 matching lines @@
 ///       "windows": new Timeout.factor(2),
 ///       "browser": [
 ///         new Skip("TODO: add browser support"),
 ///         // They'll be slow on browsers once it works on them.
 ///         new Timeout.factor(2)
 ///       ]
 ///     });
 ///
 /// If multiple platforms match, the annotations apply in order as through
 /// they were in nested groups.
-void group(String description, void body(), {String testOn, Timeout timeout,
-        skip, Map<String, dynamic> onPlatform, String tag,
-        List<String> tags}) => _declarer.group(description, body,
-            testOn: testOn, timeout: timeout, skip: skip,
-            tags: _deconvenienceTags(tag, tags));
+void group(String description, void body(),
+        {String testOn,
+        Timeout timeout,
+        skip,
+        Map<String, dynamic> onPlatform,
+        tags}) =>
+    _declarer.group(description, body,
+        testOn: testOn, timeout: timeout, skip: skip, tags: tags);
 
 /// Registers a function to be run before tests.
 ///
 /// This function will be called before each test is run. [callback] may be
 /// asynchronous; if so, it must return a [Future].
 ///
 /// If this is called within a test group, it applies only to tests in that
 /// group. [callback] will be run after any set-up callbacks in parent groups or
 /// at the top level.
 ///
@@ skipping 41 matching lines @@
 /// prefer [tearDown], and only use [tearDOwnAll] if the callback is
 /// prohibitively slow.
 void tearDownAll(callback()) => _declarer.tearDownAll(callback);
 
 /// Registers an exception that was caught for the current test.
 void registerException(error, [StackTrace stackTrace]) {
   // This will usually forward directly to [Invoker.current.handleError], but
   // going through the zone API allows other zones to consistently see errors.
   Zone.current.handleUncaughtError(error, stackTrace);
 }
-
-List<String> _deconvenienceTags(String tag, List<String> tags) {
-  var result = const[];
-  if (tag != null || (tags != null && tags.isNotEmpty)) {
-    result = [];
-    if (tag != null) result.add(tag);
-    if (tags != null && tags.isNotEmpty) result.addAll(tags);
-  }
-  return result;
-}