Only load a certain number of test suites at once.

test/runner/signal_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.
 
 // Windows doesn't support sending signals.
 @TestOn("vm && !windows")
 
 import 'dart:async';
 import 'dart:io';
 
@@ skipping 68 matching lines @@
       var line = await lineSplitter.bind(process.stdout).skip(1).first;
       expect(line, equals("in test.dart"));
       process.kill();
 
       // TODO(nweiz): Sending two signals in close succession can cause the
       // second one to be ignored, so we wait a bit before the second
       // one. Remove this hack when issue 23047 is fixed.
       await new Future.delayed(new Duration(seconds: 1));
       process.kill();
       await process.exitCode;
-      expect(new Directory(_tempDir).listSync(), isEmpty);

[kevmoo, 2015/06/25 03:18:31]

Why this change?

[nweiz, 2015/06/25 20:42:31]

We shouldn't have been testing this in the first place. The second time ^C is
sent, it's handled by Dart itself, without doing any additional cleanup. The
cleanup code is in a race with this signal handler to actually clean up the temp
dir, and the race went the other way with this CL.

     });
   });
 
   group("during test running", () {
     test("waits for a VM test to finish running", () async {
       new File(p.join(_sandbox, "test.dart")).writeAsStringSync("""
 import 'dart:async';
 import 'dart:io';
 
 import 'package:test/test.dart';
@@ skipping 156 matching lines @@
       expect(new Directory(_tempDir).listSync(), isEmpty);
     });
   });
 }
 
 Future<Process> _startTest(List<String> args) {
   new Directory(_tempDir).create();
   return startTest(args, workingDirectory: _sandbox,
       environment: {"_UNITTEST_TEMP_DIR": _tempDir});
 }