In test_runner.dart, trim spaces from a special command before checking an assert.

tools/testing/dart/test_runner.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.
 
 /**
  * Classes and methods for executing tests.
  *
  * This module includes:
  * - Managing parallel execution of tests, including timeout checks.
  * - Evaluating the output of each test as pass/fail/crash/timeout.
@@ skipping 72 matching lines @@
 
     // Special command handling. If a special command is specified
     // we have to completely rewrite the command that we are using.
     // We generate a new command-line that is the special command
     // where we replace '@' with the original command.
     var specialCommand = configuration['special-command'];
     if (!specialCommand.isEmpty()) {
       Expect.isTrue(specialCommand.contains('@'),
                     "special-command must contain a '@' char");
       var specialCommandSplit = specialCommand.split('@');
-      var prefix = specialCommandSplit[0];
-      var suffix = specialCommandSplit[1];
+      var prefix = specialCommandSplit[0].trim();
+      var suffix = specialCommandSplit[1].trim();
       List<Command> newCommands = [];
       for (Command c in commands) {
         var newExecutablePath;
         var newArguments = [];
 
         if (prefix.length > 0) {
           var prefixSplit = prefix.split(' ');
           newExecutablePath = prefixSplit[0];
           for (int i = 1; i < prefixSplit.length; i++) {
             var current = prefixSplit[i];
             if (!current.isEmpty()) newArguments.add(current);
           }
           newArguments.add(c.executable);
         }
         newArguments.addAll(c.arguments);
         var suffixSplit = suffix.split(' ');
         suffixSplit.forEach((e) {
           if (!e.isEmpty()) newArguments.add(e);
         });
         final newCommand = new Command(newExecutablePath, newArguments);
         newCommands.add(newCommand);
-        Expect.stringEquals('$prefix ${c.commandLine} $suffix',
+        // If there are extra spaces inside the prefix or suffix, this fails.
+        Expect.stringEquals('$prefix ${c.commandLine} $suffix'.trim(),
             newCommand.commandLine);
       }
       commands = newCommands;
     }
   }
 
   int get timeout() => configuration['timeout'];
 
   String get configurationString() {
     final component = configuration['component'];
@@ skipping 980 matching lines @@
         // the developer doesn't waste his or her time trying to fix a bunch of
         // tests that appear to be broken but were actually just flakes that
         // didn't get retried because there had already been one failure.
         bool allowRetry = _MAX_FAILED_NO_RETRY > _progress.numFailedTests;
         new RunningProcess(test, allowRetry, this).start();
       }
       _numProcesses++;
     }
   }
 }