[foozzie] Initial correctness fuzzer harness.

tools/foozzie/v8_commands.py

Index: tools/foozzie/v8_commands.py
diff --git a/tools/foozzie/v8_commands.py b/tools/foozzie/v8_commands.py
new file mode 100644
index 0000000000000000000000000000000000000000..643117f572b8d5cdc19195f69bac3353387fe161
--- /dev/null
+++ b/tools/foozzie/v8_commands.py
@@ -0,0 +1,65 @@
+# Copyright 2016 the V8 project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Fork from commands.py and output.py in v8 test driver.
+
+import signal
+import subprocess
+import sys
+from threading import Timer
+
+
+class Output(object):
+  def __init__(self, exit_code, timed_out, stdout, pid):
+    self.exit_code = exit_code
+    self.timed_out = timed_out
+    self.stdout = stdout
+    self.pid = pid
+
+  def HasCrashed(self):
+    # Timed out tests will have exit_code -signal.SIGTERM.
+    if self.timed_out:
+      return False
+    return (self.exit_code < 0 and
+            self.exit_code != -signal.SIGABRT)
+
+  def HasTimedOut(self):
+    return self.timed_out
+
+
+def Execute(args, cwd, timeout=None):
+  popen_args = [ c for c in args if c != "" ]

[tandrii(chromium), 2016/12/16 16:46:26]

nit-nit: space after [ and before ]

[Michael Achenbach, 2016/12/19 08:42:45]

Done.

+  try:
+    process = subprocess.Popen(
+      args=popen_args,
+      stdout=subprocess.PIPE,
+      stderr=subprocess.STDOUT,
+      cwd=cwd
+    )
+  except Exception as e:
+    sys.stderr.write("Error executing: %s\n" % popen_args)
+    raise e
+
+  def kill_process(process, timeout_result):

[tandrii(chromium), 2016/12/16 16:46:26]

why args if this func is already inside Execute closure? I'd just declerate
timeout_result above it, OR move this func outside.

[Michael Achenbach, 2016/12/19 08:42:45]

Done.

+    timeout_result[0] = True

[tandrii(chromium), 2016/12/16 16:46:26]

this code relies on this line being atomic, as well as reading it on line 61.
It's true in cPython 2.7, but it's still better to pass around threading.Event,
this line would then say event.set(), and line 61 would use event.is_set()

[Michael Achenbach, 2016/12/19 08:42:45]

Done.

+    try:
+      process.kill()
+    except OSError:
+      sys.stderr.write('Error: Process %s already ended.\n' % process.pid)
+
+  # Pseudo object to communicate with timer thread.
+  timeout_result = [False]
+
+  timer = Timer(timeout, kill_process, [process, timeout_result])
+  timer.start()
+  stdout, _ = process.communicate()
+  timer.cancel()
+
+  return Output(
+      process.returncode,
+      timeout_result[0],
+      stdout.decode('utf-8', 'replace').encode('utf-8'),
+      process.pid,
+  )
+