def _get_shard_conftest_content(self):
shard_spec = self.get_options().test_shard
if shard_spec is None:
return ''
try:
sharder = Sharder(shard_spec)
if sharder.nshards < 2:
return ''
return dedent("""
### GENERATED BY PANTS ###
def pytest_report_header(config):
return 'shard: {shard} of {nshards} (0-based shard numbering)'
def pytest_collection_modifyitems(session, config, items):
total_count = len(items)
removed = 0
def is_conftest(itm):
return itm.fspath and itm.fspath.basename == 'conftest.py'
for i, item in enumerate(list(x for x in items if not is_conftest(x))):
if i % {nshards} != {shard}:
del items[i - removed]
removed += 1
reporter = config.pluginmanager.getplugin('terminalreporter')
reporter.write_line('Only executing {{}} of {{}} total tests in shard {shard} of '
'{nshards}'.format(total_count - removed, total_count),
bold=True, invert=True, yellow=True)
""".format(shard=sharder.shard, nshards=sharder.nshards))
except Sharder.InvalidShardSpec as e:
raise self.InvalidShardSpecification(e)
def _get_sharding_args(self):
shard_spec = self.get_options().test_shard
if shard_spec is None:
return []
try:
sharder = Sharder(shard_spec)
return ["--pants-shard", f"{sharder.shard}", "--pants-num-shards", f"{sharder.nshards}"]
except Sharder.InvalidShardSpec as e:
raise self.InvalidShardSpecification(e)
def _get_sharding_args(self):
shard_spec = self.get_options().test_shard
if shard_spec is None:
return []
try:
sharder = Sharder(shard_spec)
return [
'--pants-shard', '{}'.format(sharder.shard),
'--pants-num-shards', '{}'.format(sharder.nshards)
]
except Sharder.InvalidShardSpec as e:
raise self.InvalidShardSpecification(e)
def test_compute_shard_distribution(self):
# Check that shard distribution isn't obviously broken.
nshards = 7
mean_samples_per_shard = 10000
nsamples = nshards * mean_samples_per_shard
distribution = [0] * nshards
for n in range(0, nsamples):
shard = Sharder.compute_shard(str(n), nshards)
distribution[shard] += 1
variance = sum([(x - mean_samples_per_shard) ** 2 for x in distribution]) / nshards
stddev = math.sqrt(variance)
# We arbitrarily assert that a stddev of less than 1% of the mean is good enough
# for sanity-checking purposes.
self.assertLess(stddev, 100)
def test_compute_shard_distribution(self):
# Check that shard distribution isn't obviously broken.
nshards = 7
mean_samples_per_shard = 10000
nsamples = nshards * mean_samples_per_shard
distribution = [0] * nshards
for n in range(0, nsamples):
shard = Sharder.compute_shard(str(n), nshards)
distribution[shard] += 1
variance = sum([(x - mean_samples_per_shard) ** 2 for x in distribution]) / nshards
stddev = math.sqrt(variance)
# We arbitrarily assert that a stddev of less than 1% of the mean is good enough
# for sanity-checking purposes.
self.assertLess(stddev, 100)
def _maybe_shard(self):
shard_spec = self.get_options().test_shard
if shard_spec is None:
yield []
return
try:
sharder = Sharder(shard_spec)
if sharder.nshards < 2:
yield []
return
# Note that it's important to put the tmpdir under the workdir, because pytest
# uses all arguments that look like paths to compute its rootdir, and we want
# it to pick the buildroot.
with temporary_dir(root_dir=self.workdir) as tmp:
path = os.path.join(tmp, 'conftest.py')
with open(path, 'w') as fp:
fp.write(
dedent("""
def pytest_report_header(config):
return 'shard: {shard} of {nshards} (0-based shard numbering)'
def pytest_collection_modifyitems(session, config, items):
total_count = len(items)
removed = 0
for i, item in enumerate(list(items)):
if i % {nshards} != {shard}:
del items[i - removed]
removed += 1
reporter = config.pluginmanager.getplugin('terminalreporter')
reporter.write_line('Only executing {{}} of {{}} total tests in shard {shard} of '
'{nshards}'.format(total_count - removed, total_count),
bold=True, invert=True, yellow=True)
""".format(shard=sharder.shard, nshards=sharder.nshards)))
yield [path]
except Sharder.InvalidShardSpec as e:
raise self.InvalidShardSpecification(e)
def check_bad_spec(spec):
self.assertRaises(Sharder.InvalidShardSpec, lambda: Sharder(spec))
def check(spec, expected_shard, expected_nshards):
sharder = Sharder(spec)
self.assertEqual(expected_shard, sharder.shard)
self.assertEqual(expected_nshards, sharder.nshards)
def test_compute_shard(self):
# Spot-check a couple of values, to make sure compute_shard doesn't do something
# completely degenerate.
self.assertEqual(31, Sharder.compute_shard('', 42))
self.assertEqual(35, Sharder.compute_shard('foo', 42))
self.assertEqual(5, Sharder.compute_shard('bar', 42))
def test_compute_shard(self):
# Spot-check a couple of values, to make sure compute_shard doesn't do something
# completely degenerate.
self.assertEqual(31, Sharder.compute_shard('', 42))
self.assertEqual(35, Sharder.compute_shard('foo', 42))
self.assertEqual(5, Sharder.compute_shard('bar', 42))
