Continuously update the compact reporter's clock.

test/runner/compact_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:io';
 
 import 'package:path/path.dart' as p;
 import 'package:test/src/util/io.dart';
@@ skipping 351 matching lines @@
     new File(p.join(path, "test.dart")).writeAsStringSync(dart);
     if (args == null) args = [];
     args = args.toList()
       ..add("test.dart")
       ..add("--concurrency=$concurrency")
       ..add("--reporter=compact");
     var result = runTest(args, workingDirectory: path);
 
     // Convert CRs into newlines, remove excess trailing whitespace, and trim
     // off timestamps.
+    var lastLine;
     var actual = result.stdout.trim().split(new RegExp(r"[\r\n]")).map((line) {
       if (line.startsWith("  ") || line.isEmpty) return line.trimRight();
-      return line.trim().replaceFirst(new RegExp("^[0-9]{2}:[0-9]{2} "), "");
-    }).join("\n");
+
+      var trimmed = line.trim()
+          .replaceFirst(new RegExp("^[0-9]{2}:[0-9]{2} "), "");
+
+      // Trim identical lines so the test isn't dependent on how fast each test
+      // runs.
+      if (trimmed == lastLine) return null;
+      lastLine = trimmed;
+      return trimmed;
+    }).where((line) => line != null).join("\n");
 
     // Un-indent the expected string.
     var indentation = expected.indexOf(new RegExp("[^ ]"));
     expected = expected.split("\n").map((line) {
       if (line.isEmpty) return line;
       return line.substring(indentation);
     }).join("\n");
 
     expect(actual, equals(expected));
   }), completes);
 }