Modify the sharding supervisor to support sharding only a sub-shard of a test suite.

sharding_supervisor_unittest.py

+#!/usr/bin/env python
+# Copyright (c) 2012 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.
+
+"""Verify basic usage of sharding_supervisor."""
+
+import os
+import subprocess
+import sys
+import unittest
+
+import sharding_supervisor
+
+SHARDING_SUPERVISOR = os.path.join(os.path.dirname(sys.argv[0]),
+                                   'sharding_supervisor.py')
+DUMMY_TEST = os.path.join(os.path.dirname(sys.argv[0]), 'dummy_test.py')
+NUM_CORES = sharding_supervisor.DetectNumCores()
+SHARDS_PER_CORE = sharding_supervisor.SS_DEFAULT_SHARDS_PER_CORE
+

[M-A Ruel, 2012/04/05 00:53:58]

2 lines.

[nsylvain, 2012/04/05 01:15:58]

Done.

+def GenerateExpectedOutput(start, end, num_shards):

[M-A Ruel, 2012/04/05 00:53:58]

In general, I prefer new code to use PEP8 names.

[nsylvain, 2012/04/05 01:15:58]

Done.

+  """Generate the expected stdout and stderr for the dummy test."""
+  stdout = ''
+  for i in range(start, end):

[M-A Ruel, 2012/04/05 00:53:58]

If I were picky, I'd tell you to use xrange(). You can ask Stefan how much he
likes to be told that. :)

[nsylvain, 2012/04/05 01:15:58]

Good thing you are not picky.

+    stdout += 'Running shard %d of %d\n' % (i, num_shards)

[M-A Ruel, 2012/04/05 00:53:58]

stdout = ''.join(
    'Running shard %d of %d\n' % (i, num_shards)
    for i in xrange(start, end))

[nsylvain, 2012/04/05 01:15:58]

I actually don't find this code more readable and it's the same number of lines
and something like 5 more chars.

+  stderr = '\nALL SHARDS PASSED!\nALL TESTS PASSED!\n'
+
+  return (stdout, stderr)
+
+
+class ShardingSupervisorUnittest(unittest.TestCase):
+  def testBasicRun(self):
+    # Default test.
+    expected_shards = NUM_CORES * SHARDS_PER_CORE
+    (expected_out, expected_err) = GenerateExpectedOutput(0, expected_shards,

[M-A Ruel, 2012/04/05 00:53:58]

This kind of alignment makes me sad. :/

[nsylvain, 2012/04/05 01:15:58]

what about this one?

+                                                          expected_shards)
+    p = subprocess.Popen([SHARDING_SUPERVISOR, '--no-color', DUMMY_TEST],
+                         stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+    p.wait();

[M-A Ruel, 2012/04/05 00:53:58]

; ?

p.wait()?
See http://docs.python.org/library/subprocess.html#subprocess.Popen.wait

[nsylvain, 2012/04/05 01:15:58]

Done.

+    self.assertEqual(expected_out, p.stdout.read())
+    self.assertEqual(expected_err, p.stderr.read())
+    self.assertEqual(0, p.returncode)
+
+  def testShardPerCore(self):
+    """Test the --shards_per_core parameter."""
+    expected_shards = NUM_CORES * 25
+    (expected_out, expected_err) = GenerateExpectedOutput(0, expected_shards,
+                                                          expected_shards)
+    p = subprocess.Popen([SHARDING_SUPERVISOR, '--no-color',
+                          '--shards_per_core', '25', DUMMY_TEST],
+                         stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+    p.wait();
+    self.assertEqual(expected_out, p.stdout.read())
+    self.assertEqual(expected_err, p.stderr.read())
+    self.assertEqual(0, p.returncode)
+
+  def testSlaveSharding(self):
+    """Test the --total-slaves and --slave-index parameters."""
+    total_shards = 6
+    expected_shards = NUM_CORES * SHARDS_PER_CORE * total_shards
+
+    # Test every single index to make sure they run correctly.
+    for index in range(total_shards):
+      begin = NUM_CORES * SHARDS_PER_CORE * index
+      end = begin + NUM_CORES * SHARDS_PER_CORE
+      (expected_out, expected_err) = GenerateExpectedOutput(begin, end,
+                                                            expected_shards)
+      p = subprocess.Popen([SHARDING_SUPERVISOR, '--no-color',
+                            '--total-slaves', str(total_shards),
+                            '--slave-index', str(index),
+                            DUMMY_TEST],
+                           stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+      p.wait();
+      self.assertEqual(expected_out, p.stdout.read())
+      self.assertEqual(expected_err, p.stderr.read())
+      self.assertEqual(0, p.returncode)
+
+
+if __name__ == '__main__':
+  unittest.main()