Add metadata to messages emitted by live tests.

test/runner/json_reporter_test.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.
 
 @TestOn("vm")
 
 import 'dart:convert';
 
 import 'package:path/path.dart' as p;
 import 'package:scheduled_test/descriptor.dart' as d;
@@ skipping 369 matching lines @@
         test('skip 1', () {}, skip: 'some reason');
         test('skip 2', () {}, skip: 'or another');
       """, [
         _start,
          _allSuites(),
         _suite(0),
         _testStart(1, "loading test.dart", groupIDs: []),
         _testDone(1, hidden: true),
         _group(2, testCount: 2),
         _testStart(3, "skip 1", skip: "some reason", line: 6, column: 9),
+        _print(3, "Skip: some reason", type: "skip"),
         _testDone(3, skipped: true),
         _testStart(4, "skip 2", skip: "or another", line: 7, column: 9),
+        _print(4, "Skip: or another", type: "skip"),
         _testDone(4, skipped: true),
         _done()
       ]);
     });
   });
 
   group("reports line and column numbers for", () {
     test("the first call to setUpAll()", () {
       _expectReport("""
         setUpAll(() {});
@@ skipping 193 matching lines @@
       "line": line,
       "column": column,
       "url":
           line == null ? null : p.toUri(p.join(sandbox, "test.dart")).toString()
     }
   };
 }
 
 /// Returns the event emitted by the JSON reporter indicating that a test
 /// printed [message].
-Map _print(int id, String message) {
+Map _print(int id, String message, {String type}) {
   return {
     "type": "print",
     "testID": id,
-    "message": message
+    "message": message,
+    "messageType": type ?? "print"
   };
 }
 
 /// Returns the event emitted by the JSON reporter indicating that a test
 /// emitted [error].
 ///
 /// The [isFailure] parameter indicates whether the error was a [TestFailure] or
 /// not.
 Map _error(int id, String error, {bool isFailure: false}) {
   return {
@@ skipping 32 matching lines @@
 /// Returns the serialized metadata corresponding to [skip].
 Map _metadata({skip}) {
   if (skip == true) {
     return {"skip": true, "skipReason": null};
   } else if (skip is String) {
     return {"skip": true, "skipReason": skip};
   } else {
     return {"skip": false, "skipReason": null};
   }
 }