A basic utility to allow running of tests on VMs in parallel.

Current usage is simple: just specify a list of tests and each one will be run
on a separate VM using the latest image on a default board. Exit code is
non-zero if any of the tests fail. Output from separate tests is interleaved.

More CLs to follow -- specifying a result directory, non-interleaved output,
base ssh port, board, image path, etc.

BUG=8585
TEST=./bin/cros_run_parallel_vm_tests suite_Smoke suite_Smoke

Change-Id: Ifa3396768050905ec02e4cad8b8f065a6d129154

Review URL: http://codereview.chromium.org/4337003

bin/cros_run_parallel_vm_tests

@@ -0,0 +1 @@
+cros_run_parallel_vm_tests.py

bin/cros_run_parallel_vm_tests.py

@@ -0,0 +1,92 @@
+#!/usr/bin/python
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Runs tests on VMs in parallel."""
+
+import optparse
+import os
+import subprocess
+import sys
+
+sys.path.append(os.path.join(os.path.dirname(__file__), '../lib'))
+from cros_build_lib import Die
+from cros_build_lib import Info
+
+
+class ParallelTestRunner(object):
+  """Runs tests on VMs in parallel."""
+
+  _DEFAULT_START_SSH_PORT = 9222
+
+  def __init__(self, tests):
+    self._tests = tests
+
+  def _SpawnTests(self):
+    """Spawns VMs and starts the test runs on them.
+
+    Runs all tests in |self._tests|. Each test is executed on a separate VM.
+
+    Returns: A list of test process info objects containing the following
+    dictionary entries:
+      'test': the test name;
+      'proc': the Popen process instance for this test run.
+    """
+    ssh_port = self._DEFAULT_START_SSH_PORT
+    spawned_tests = []
+    # Test runs shouldn't need anything from stdin. However, it seems that
+    # running with stdin leaves the terminal in a bad state so redirect from
+    # /dev/null.
+    dev_null = open('/dev/null')
+    for test in self._tests:
+      args = [ os.path.join(os.path.dirname(__file__), 'cros_run_vm_test'),
+               '--snapshot',  # The image is shared so don't modify it.
+               '--no_graphics',
+               '--ssh_port=%d' % ssh_port,
+               '--test_case=%s' % test ]
+      Info('Running %r...' % args)
+      proc = subprocess.Popen(args, stdin=dev_null)
+      test_info = { 'test': test,
+                    'proc': proc }
+      spawned_tests.append(test_info)
+      ssh_port = ssh_port + 1
+    return spawned_tests
+
+  def _WaitForCompletion(self, spawned_tests):
+    """Waits for tests to complete and returns a list of failed tests.
+
+    Arguments:
+      spawned_tests: A list of test info objects (see _SpawnTests).
+
+    Returns: A list of failed test names.
+    """
+    failed_tests = []
+    for test_info in spawned_tests:
+      proc = test_info['proc']
+      proc.wait()
+      if proc.returncode: failed_tests.append(test_info['test'])
+    return failed_tests
+
+  def Run(self):
+    """Runs the tests in |self._tests| on separate VMs in parallel."""
+    spawned_tests = self._SpawnTests()
+    failed_tests = self._WaitForCompletion(spawned_tests)
+    if failed_tests: Die('Tests failed: %r' % failed_tests)
+
+
+def main():
+  usage = 'Usage: %prog [options] tests...'
+  parser = optparse.OptionParser(usage=usage)
+  (options, args) = parser.parse_args()
+
+  if not args:
+    parser.print_help()
+    Die('no tests provided')
+
+  runner = ParallelTestRunner(args)
+  runner.Run()
+
+
+if __name__ == '__main__':
+  main()