Add test that test.dart returns non-zero exit code for failing runs.

tests/standalone/io/test_runner_exit_code_test.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.
+
+#import('dart:io');
+
+void runTests(String executable, String script, Iterator iterator) {

[ahe, 2012/10/08 07:58:55]

Consider using a list instead of an iterator...

+  if (iterator.hasNext()) {
+    var progressIndicator = iterator.next();

[ahe, 2012/10/08 07:58:56]

... then these two lines can be:

for (String progressIndicator in list) {

[Mads Ager (google), 2012/10/08 08:00:49]

They could, but then you would start all the processes at once. I'm doing it
this way so we start one process at a time. I use the iterator to hold the state
between callbacks through the event loop.

[ahe, 2012/10/08 08:02:43]

Doh. I misread the code :-)

+    Process.run(executable, [script, progressIndicator]).then((result) {
+      Expect.equals(1, result.exitCode);
+      if (progressIndicator == 'buildbot') {
+        Expect.isTrue(result.stdout.contains("@@@STEP_FAILURE@@@"));

[Emily Fortuna, 2012/10/08 17:50:06]

The "@@@STEP_FAILURE@@" string is only printed out for dart2js and browser bots.
The dart2dart, dartc and dart VM bots only use the exit code instead to detect
failure.

+      }
+      runTests(executable, script, iterator);
+    });
+  }
+}
+
+main() {
+  var scriptPath = new Path.fromNative(new Options().script);
+  var scriptDirPath = scriptPath.directoryPath;
+  var exitCodeScriptPath =
+    scriptDirPath.append('test_runner_exit_code_script.dart');
+  var script = exitCodeScriptPath.toNativePath();
+  var executable = new Options().executable;
+  var progressTypes = ['compact', 'color', 'line', 'verbose',
+                       'status', 'buildbot'];
+  var iterator = progressTypes.iterator();
+  runTests(executable, script, iterator);
+}