gh-110722: Make `-m test -T -j` use sys.monitoring (GH-111710)

Now all results from worker processes are aggregated and
displayed together as a summary at the end of a regrtest run.

The traditional trace is left in place for use with sequential
in-process test runs but now raises a warning that those
numbers are not precise.

`-T -j` requires `--with-pydebug` as it relies on `-Xpresite=`.
This commit is contained in:
Łukasz Langa 2023-11-10 18:17:45 +01:00 committed by GitHub
parent 0b06d2482d
commit 3932b0f7b1
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13 changed files with 166 additions and 34 deletions

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@ -187,7 +187,8 @@ Programmatic Interface
Merge in data from another :class:`CoverageResults` object.
.. method:: write_results(show_missing=True, summary=False, coverdir=None)
.. method:: write_results(show_missing=True, summary=False, coverdir=None,\
*, ignore_missing_files=False)
Write coverage results. Set *show_missing* to show lines that had no
hits. Set *summary* to include in the output the coverage summary per
@ -195,6 +196,13 @@ Programmatic Interface
result files will be output. If ``None``, the results for each source
file are placed in its directory.
If *ignore_missing_files* is ``True``, coverage counts for files that no
longer exist are silently ignored. Otherwise, a missing file will
raise a :exc:`FileNotFoundError`.
.. versionchanged:: 3.13
Added *ignore_missing_files* parameter.
A simple example demonstrating the use of the programmatic interface::
import sys

48
Lib/test/cov.py Normal file
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@ -0,0 +1,48 @@
"""A minimal hook for gathering line coverage of the standard library.
Designed to be used with -Xpresite= which means:
* it installs itself on import
* it's not imported as `__main__` so can't use the ifmain idiom
* it can't import anything besides `sys` to avoid tainting gathered coverage
* filenames are not normalized
To get gathered coverage back, look for 'test.cov' in `sys.modules`
instead of importing directly. That way you can determine if the module
was already in use.
If you need to disable the hook, call the `disable()` function.
"""
import sys
mon = sys.monitoring
FileName = str
LineNo = int
Location = tuple[FileName, LineNo]
coverage: set[Location] = set()
# `types` and `typing` aren't imported to avoid invalid coverage
def add_line(
code: "types.CodeType",
lineno: int,
) -> "typing.Literal[sys.monitoring.DISABLE]":
coverage.add((code.co_filename, lineno))
return mon.DISABLE
def enable():
mon.use_tool_id(mon.COVERAGE_ID, "regrtest coverage")
mon.register_callback(mon.COVERAGE_ID, mon.events.LINE, add_line)
mon.set_events(mon.COVERAGE_ID, mon.events.LINE)
def disable():
mon.set_events(mon.COVERAGE_ID, 0)
mon.register_callback(mon.COVERAGE_ID, mon.events.LINE, None)
mon.free_tool_id(mon.COVERAGE_ID)
enable()

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@ -2,7 +2,7 @@ import argparse
import os.path
import shlex
import sys
from test.support import os_helper
from test.support import os_helper, Py_DEBUG
from .utils import ALL_RESOURCES, RESOURCE_NAMES
@ -448,8 +448,16 @@ def _parse_args(args, **kwargs):
if ns.single and ns.fromfile:
parser.error("-s and -f don't go together!")
if ns.use_mp is not None and ns.trace:
parser.error("-T and -j don't go together!")
if ns.trace:
if ns.use_mp is not None:
if not Py_DEBUG:
parser.error("need --with-pydebug to use -T and -j together")
else:
print(
"Warning: collecting coverage without -j is imprecise. Configure"
" --with-pydebug and run -m test -T -j for best results.",
file=sys.stderr
)
if ns.python is not None:
if ns.use_mp is None:
parser.error("-p requires -j!")

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@ -5,6 +5,7 @@ import shlex
import sys
import sysconfig
import time
import trace
from test import support
from test.support import os_helper, MS_WINDOWS
@ -13,7 +14,7 @@ from .cmdline import _parse_args, Namespace
from .findtests import findtests, split_test_packages, list_cases
from .logger import Logger
from .pgo import setup_pgo_tests
from .result import State
from .result import State, TestResult
from .results import TestResults, EXITCODE_INTERRUPTED
from .runtests import RunTests, HuntRefleak
from .setup import setup_process, setup_test_dir
@ -284,7 +285,9 @@ class Regrtest:
self.results.display_result(runtests.tests,
self.quiet, self.print_slowest)
def run_test(self, test_name: TestName, runtests: RunTests, tracer):
def run_test(
self, test_name: TestName, runtests: RunTests, tracer: trace.Trace | None
) -> TestResult:
if tracer is not None:
# If we're tracing code coverage, then we don't exit with status
# if on a false return value from main.
@ -292,6 +295,7 @@ class Regrtest:
namespace = dict(locals())
tracer.runctx(cmd, globals=globals(), locals=namespace)
result = namespace['result']
result.covered_lines = list(tracer.counts)
else:
result = run_single_test(test_name, runtests)
@ -299,9 +303,8 @@ class Regrtest:
return result
def run_tests_sequentially(self, runtests):
def run_tests_sequentially(self, runtests) -> None:
if self.coverage:
import trace
tracer = trace.Trace(trace=False, count=True)
else:
tracer = None
@ -349,8 +352,6 @@ class Regrtest:
if previous_test:
print(previous_test)
return tracer
def get_state(self):
state = self.results.get_state(self.fail_env_changed)
if self.first_state:
@ -361,7 +362,7 @@ class Regrtest:
from .run_workers import RunWorkers
RunWorkers(num_workers, runtests, self.logger, self.results).run()
def finalize_tests(self, tracer):
def finalize_tests(self, coverage: trace.CoverageResults | None) -> None:
if self.next_single_filename:
if self.next_single_test:
with open(self.next_single_filename, 'w') as fp:
@ -369,10 +370,10 @@ class Regrtest:
else:
os.unlink(self.next_single_filename)
if tracer is not None:
results = tracer.results()
results.write_results(show_missing=True, summary=True,
coverdir=self.coverage_dir)
if coverage is not None:
coverage.write_results(show_missing=True, summary=True,
coverdir=self.coverage_dir,
ignore_missing_files=True)
if self.want_run_leaks:
os.system("leaks %d" % os.getpid())
@ -412,6 +413,7 @@ class Regrtest:
hunt_refleak=self.hunt_refleak,
test_dir=self.test_dir,
use_junit=(self.junit_filename is not None),
coverage=self.coverage,
memory_limit=self.memory_limit,
gc_threshold=self.gc_threshold,
use_resources=self.use_resources,
@ -458,10 +460,10 @@ class Regrtest:
try:
if self.num_workers:
self._run_tests_mp(runtests, self.num_workers)
tracer = None
else:
tracer = self.run_tests_sequentially(runtests)
self.run_tests_sequentially(runtests)
coverage = self.results.get_coverage_results()
self.display_result(runtests)
if self.want_rerun and self.results.need_rerun():
@ -471,7 +473,7 @@ class Regrtest:
self.logger.stop_load_tracker()
self.display_summary()
self.finalize_tests(tracer)
self.finalize_tests(coverage)
return self.results.get_exitcode(self.fail_env_changed,
self.fail_rerun)

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@ -78,6 +78,11 @@ class State:
}
FileName = str
LineNo = int
Location = tuple[FileName, LineNo]
@dataclasses.dataclass(slots=True)
class TestResult:
test_name: TestName
@ -91,6 +96,9 @@ class TestResult:
errors: list[tuple[str, str]] | None = None
failures: list[tuple[str, str]] | None = None
# partial coverage in a worker run; not used by sequential in-process runs
covered_lines: list[Location] | None = None
def is_failed(self, fail_env_changed: bool) -> bool:
if self.state == State.ENV_CHANGED:
return fail_env_changed
@ -207,6 +215,10 @@ def _decode_test_result(data: dict[str, Any]) -> TestResult | dict[str, Any]:
data.pop('__test_result__')
if data['stats'] is not None:
data['stats'] = TestStats(**data['stats'])
if data['covered_lines'] is not None:
data['covered_lines'] = [
tuple(loc) for loc in data['covered_lines']
]
return TestResult(**data)
else:
return data

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@ -1,13 +1,14 @@
import sys
import trace
from .runtests import RunTests
from .result import State, TestResult, TestStats
from .result import State, TestResult, TestStats, Location
from .utils import (
StrPath, TestName, TestTuple, TestList, FilterDict,
printlist, count, format_duration)
# Python uses exit code 1 when an exception is not catched
# Python uses exit code 1 when an exception is not caught
# argparse.ArgumentParser.error() uses exit code 2
EXITCODE_BAD_TEST = 2
EXITCODE_ENV_CHANGED = 3
@ -34,6 +35,8 @@ class TestResults:
self.stats = TestStats()
# used by --junit-xml
self.testsuite_xml: list[str] = []
# used by -T with -j
self.covered_lines: set[Location] = set()
def is_all_good(self):
return (not self.bad
@ -119,11 +122,17 @@ class TestResults:
self.stats.accumulate(result.stats)
if rerun:
self.rerun.append(test_name)
if result.covered_lines:
# we don't care about trace counts so we don't have to sum them up
self.covered_lines.update(result.covered_lines)
xml_data = result.xml_data
if xml_data:
self.add_junit(xml_data)
def get_coverage_results(self) -> trace.CoverageResults:
counts = {loc: 1 for loc in self.covered_lines}
return trace.CoverageResults(counts=counts)
def need_rerun(self):
return bool(self.rerun_results)

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@ -277,7 +277,7 @@ class WorkerThread(threading.Thread):
# Python finalization: too late for libregrtest.
if not support.is_wasi:
# Don't check for leaked temporary files and directories if Python is
# run on WASI. WASI don't pass environment variables like TMPDIR to
# run on WASI. WASI doesn't pass environment variables like TMPDIR to
# worker processes.
tmp_dir = tempfile.mkdtemp(prefix="test_python_")
tmp_dir = os.path.abspath(tmp_dir)

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@ -85,6 +85,7 @@ class RunTests:
hunt_refleak: HuntRefleak | None
test_dir: StrPath | None
use_junit: bool
coverage: bool
memory_limit: str | None
gc_threshold: int | None
use_resources: tuple[str, ...]

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@ -4,7 +4,7 @@ import os
from typing import Any, NoReturn
from test import support
from test.support import os_helper
from test.support import os_helper, Py_DEBUG
from .setup import setup_process, setup_test_dir
from .runtests import RunTests, JsonFile, JsonFileType
@ -30,6 +30,8 @@ def create_worker_process(runtests: RunTests, output_fd: int,
python_opts = [opt for opt in python_opts if opt != "-E"]
else:
executable = (sys.executable,)
if runtests.coverage:
python_opts.append("-Xpresite=test.cov")
cmd = [*executable, *python_opts,
'-u', # Unbuffered stdout and stderr
'-m', 'test.libregrtest.worker',
@ -87,6 +89,18 @@ def worker_process(worker_json: StrJSON) -> NoReturn:
print(f"Re-running {test_name} in verbose mode", flush=True)
result = run_single_test(test_name, runtests)
if runtests.coverage:
if "test.cov" in sys.modules: # imported by -Xpresite=
result.covered_lines = list(sys.modules["test.cov"].coverage)
elif not Py_DEBUG:
print(
"Gathering coverage in worker processes requires --with-pydebug",
flush=True,
)
else:
raise LookupError(
"`test.cov` not found in sys.modules but coverage wanted"
)
if json_file.file_type == JsonFileType.STDOUT:
print()

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@ -1082,18 +1082,30 @@ def check_impl_detail(**guards):
def no_tracing(func):
"""Decorator to temporarily turn off tracing for the duration of a test."""
if not hasattr(sys, 'gettrace'):
return func
else:
trace_wrapper = func
if hasattr(sys, 'gettrace'):
@functools.wraps(func)
def wrapper(*args, **kwargs):
def trace_wrapper(*args, **kwargs):
original_trace = sys.gettrace()
try:
sys.settrace(None)
return func(*args, **kwargs)
finally:
sys.settrace(original_trace)
return wrapper
coverage_wrapper = trace_wrapper
if 'test.cov' in sys.modules: # -Xpresite=test.cov used
cov = sys.monitoring.COVERAGE_ID
@functools.wraps(func)
def coverage_wrapper(*args, **kwargs):
original_events = sys.monitoring.get_events(cov)
try:
sys.monitoring.set_events(cov, 0)
return trace_wrapper(*args, **kwargs)
finally:
sys.monitoring.set_events(cov, original_events)
return coverage_wrapper
def refcount_test(test):

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@ -306,13 +306,23 @@ class ParseArgsTestCase(unittest.TestCase):
self.assertEqual(ns.use_mp, 2)
self.checkError([opt], 'expected one argument')
self.checkError([opt, 'foo'], 'invalid int value')
self.checkError([opt, '2', '-T'], "don't go together")
self.checkError([opt, '0', '-T'], "don't go together")
def test_coverage(self):
def test_coverage_sequential(self):
for opt in '-T', '--coverage':
with self.subTest(opt=opt):
ns = self.parse_args([opt])
with support.captured_stderr() as stderr:
ns = self.parse_args([opt])
self.assertTrue(ns.trace)
self.assertIn(
"collecting coverage without -j is imprecise",
stderr.getvalue(),
)
@unittest.skipUnless(support.Py_DEBUG, 'need a debug build')
def test_coverage_mp(self):
for opt in '-T', '--coverage':
with self.subTest(opt=opt):
ns = self.parse_args([opt, '-j1'])
self.assertTrue(ns.trace)
def test_coverdir(self):

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@ -202,7 +202,8 @@ class CoverageResults:
for key in other_callers:
callers[key] = 1
def write_results(self, show_missing=True, summary=False, coverdir=None):
def write_results(self, show_missing=True, summary=False, coverdir=None, *,
ignore_missing_files=False):
"""
Write the coverage results.
@ -211,6 +212,9 @@ class CoverageResults:
:param coverdir: If None, the results of each module are placed in its
directory, otherwise it is included in the directory
specified.
:param ignore_missing_files: If True, counts for files that no longer
exist are silently ignored. Otherwise, a missing file
will raise a FileNotFoundError.
"""
if self.calledfuncs:
print()
@ -253,6 +257,9 @@ class CoverageResults:
if filename.endswith(".pyc"):
filename = filename[:-1]
if ignore_missing_files and not os.path.isfile(filename):
continue
if coverdir is None:
dir = os.path.dirname(os.path.abspath(filename))
modulename = _modname(filename)
@ -278,7 +285,6 @@ class CoverageResults:
percent = int(100 * n_hits / n_lines)
sums[modulename] = n_lines, percent, modulename, filename
if summary and sums:
print("lines cov% module (path)")
for m in sorted(sums):

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@ -0,0 +1,2 @@
Gathering line coverage of standard libraries within the regression test
suite is now precise, as well as much faster. Patch by Łukasz Langa.