Use subprocess42 in recipe_engine to avoid threading madness.

recipes/engine_tests/bad_subprocess.py

+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Tests that daemons that hang on to STDOUT can't cause the engine to hang."""
+
+DEPS = [
+  'python',
+]
+
+def RunSteps(api):
+  api.python.inline("bad deamon", """
+  import os
+  import time
+  import sys
+
+  print "parent"
+  pid = os.fork()
+  if pid > 0:
+    "parent leaves"
+    sys.exit(0)
+
+  print "child"
+  pid = os.fork()
+  if pid > 0:
+    "child leaves"
+    sys.exit(0)
+
+  print "daemon sleepin'"
+  time.sleep(30)
+
+  print "ROAAARRRR!!!"
+  """)
+
+def GenTests(api):
+  yield api.test('basic')
+