Issue #25220: Move most regrtest.py code to libregrtest

Lib/test/libregrtest/__init__.py

@@ -1 +1,2 @@
 from test.libregrtest.cmdline import _parse_args, RESOURCE_NAMES
+from test.libregrtest.main import main_in_temp_cwd

Lib/test/libregrtest/cmdline.py

@@ -1,9 +1,9 @@
 import argparse
 import faulthandler
 import os
-
 from test import support
 
+
 USAGE = """\
 python -m test [options] [test_name1 [test_name2 ...]]
 python path/to/Lib/test/regrtest.py [options] [test_name1 [test_name2 ...]]

Lib/test/libregrtest/main.py

@@ -0,0 +1,547 @@
+import faulthandler
+import json
+import os
+import re
+import sys
+import tempfile
+import sysconfig
+import signal
+import random
+import platform
+import traceback
+import unittest
+from test.libregrtest.runtest import (
+    findtests, runtest, run_test_in_subprocess,
+    STDTESTS, NOTTESTS,
+    PASSED, FAILED, ENV_CHANGED, SKIPPED,
+    RESOURCE_DENIED, INTERRUPTED, CHILD_ERROR)
+from test.libregrtest.refleak import warm_caches
+from test.libregrtest.cmdline import _parse_args
+from test import support
+try:
+    import threading
+except ImportError:
+    threading = None
+
+
+# Some times __path__ and __file__ are not absolute (e.g. while running from
+# Lib/) and, if we change the CWD to run the tests in a temporary dir, some
+# imports might fail.  This affects only the modules imported before os.chdir().
+# These modules are searched first in sys.path[0] (so '' -- the CWD) and if
+# they are found in the CWD their __file__ and __path__ will be relative (this
+# happens before the chdir).  All the modules imported after the chdir, are
+# not found in the CWD, and since the other paths in sys.path[1:] are absolute
+# (site.py absolutize them), the __file__ and __path__ will be absolute too.
+# Therefore it is necessary to absolutize manually the __file__ and __path__ of
+# the packages to prevent later imports to fail when the CWD is different.
+for module in sys.modules.values():
+    if hasattr(module, '__path__'):
+        module.__path__ = [os.path.abspath(path) for path in module.__path__]
+    if hasattr(module, '__file__'):
+        module.__file__ = os.path.abspath(module.__file__)
+
+
+# MacOSX (a.k.a. Darwin) has a default stack size that is too small
+# for deeply recursive regular expressions.  We see this as crashes in
+# the Python test suite when running test_re.py and test_sre.py.  The
+# fix is to set the stack limit to 2048.
+# This approach may also be useful for other Unixy platforms that
+# suffer from small default stack limits.
+if sys.platform == 'darwin':
+    try:
+        import resource
+    except ImportError:
+        pass
+    else:
+        soft, hard = resource.getrlimit(resource.RLIMIT_STACK)
+        newsoft = min(hard, max(soft, 1024*2048))
+        resource.setrlimit(resource.RLIMIT_STACK, (newsoft, hard))
+
+
+# When tests are run from the Python build directory, it is best practice
+# to keep the test files in a subfolder.  This eases the cleanup of leftover
+# files using the "make distclean" command.
+if sysconfig.is_python_build():
+    TEMPDIR = os.path.join(sysconfig.get_config_var('srcdir'), 'build')
+else:
+    TEMPDIR = tempfile.gettempdir()
+TEMPDIR = os.path.abspath(TEMPDIR)
+
+
+def main(tests=None, **kwargs):
+    """Execute a test suite.
+
+    This also parses command-line options and modifies its behavior
+    accordingly.
+
+    tests -- a list of strings containing test names (optional)
+    testdir -- the directory in which to look for tests (optional)
+
+    Users other than the Python test suite will certainly want to
+    specify testdir; if it's omitted, the directory containing the
+    Python test suite is searched for.
+
+    If the tests argument is omitted, the tests listed on the
+    command-line will be used.  If that's empty, too, then all *.py
+    files beginning with test_ will be used.
+
+    The other default arguments (verbose, quiet, exclude,
+    single, randomize, findleaks, use_resources, trace, coverdir,
+    print_slow, and random_seed) allow programmers calling main()
+    directly to set the values that would normally be set by flags
+    on the command line.
+    """
+    # Display the Python traceback on fatal errors (e.g. segfault)
+    faulthandler.enable(all_threads=True)
+
+    # Display the Python traceback on SIGALRM or SIGUSR1 signal
+    signals = []
+    if hasattr(signal, 'SIGALRM'):
+        signals.append(signal.SIGALRM)
+    if hasattr(signal, 'SIGUSR1'):
+        signals.append(signal.SIGUSR1)
+    for signum in signals:
+        faulthandler.register(signum, chain=True)
+
+    replace_stdout()
+
+    support.record_original_stdout(sys.stdout)
+
+    ns = _parse_args(sys.argv[1:], **kwargs)
+
+    if ns.huntrleaks:
+        # Avoid false positives due to various caches
+        # filling slowly with random data:
+        warm_caches()
+    if ns.memlimit is not None:
+        support.set_memlimit(ns.memlimit)
+    if ns.threshold is not None:
+        import gc
+        gc.set_threshold(ns.threshold)
+    if ns.nowindows:
+        import msvcrt
+        msvcrt.SetErrorMode(msvcrt.SEM_FAILCRITICALERRORS|
+                            msvcrt.SEM_NOALIGNMENTFAULTEXCEPT|
+                            msvcrt.SEM_NOGPFAULTERRORBOX|
+                            msvcrt.SEM_NOOPENFILEERRORBOX)
+        try:
+            msvcrt.CrtSetReportMode
+        except AttributeError:
+            # release build
+            pass
+        else:
+            for m in [msvcrt.CRT_WARN, msvcrt.CRT_ERROR, msvcrt.CRT_ASSERT]:
+                msvcrt.CrtSetReportMode(m, msvcrt.CRTDBG_MODE_FILE)
+                msvcrt.CrtSetReportFile(m, msvcrt.CRTDBG_FILE_STDERR)
+    if ns.wait:
+        input("Press any key to continue...")
+
+    if ns.slaveargs is not None:
+        args, kwargs = json.loads(ns.slaveargs)
+        if kwargs.get('huntrleaks'):
+            unittest.BaseTestSuite._cleanup = False
+        try:
+            result = runtest(*args, **kwargs)
+        except KeyboardInterrupt:
+            result = INTERRUPTED, ''
+        except BaseException as e:
+            traceback.print_exc()
+            result = CHILD_ERROR, str(e)
+        sys.stdout.flush()
+        print()   # Force a newline (just in case)
+        print(json.dumps(result))
+        sys.exit(0)
+
+    good = []
+    bad = []
+    skipped = []
+    resource_denieds = []
+    environment_changed = []
+    interrupted = False
+
+    if ns.findleaks:
+        try:
+            import gc
+        except ImportError:
+            print('No GC available, disabling findleaks.')
+            ns.findleaks = False
+        else:
+            # Uncomment the line below to report garbage that is not
+            # freeable by reference counting alone.  By default only
+            # garbage that is not collectable by the GC is reported.
+            #gc.set_debug(gc.DEBUG_SAVEALL)
+            found_garbage = []
+
+    if ns.huntrleaks:
+        unittest.BaseTestSuite._cleanup = False
+
+    if ns.single:
+        filename = os.path.join(TEMPDIR, 'pynexttest')
+        try:
+            with open(filename, 'r') as fp:
+                next_test = fp.read().strip()
+                tests = [next_test]
+        except OSError:
+            pass
+
+    if ns.fromfile:
+        tests = []
+        with open(os.path.join(support.SAVEDCWD, ns.fromfile)) as fp:
+            count_pat = re.compile(r'\[\s*\d+/\s*\d+\]')
+            for line in fp:
+                line = count_pat.sub('', line)
+                guts = line.split() # assuming no test has whitespace in its name
+                if guts and not guts[0].startswith('#'):
+                    tests.extend(guts)
+
+    # Strip .py extensions.
+    removepy(ns.args)
+    removepy(tests)
+
+    stdtests = STDTESTS[:]
+    nottests = NOTTESTS.copy()
+    if ns.exclude:
+        for arg in ns.args:
+            if arg in stdtests:
+                stdtests.remove(arg)
+            nottests.add(arg)
+        ns.args = []
+
+    # For a partial run, we do not need to clutter the output.
+    if ns.verbose or ns.header or not (ns.quiet or ns.single or tests or ns.args):
+        # Print basic platform information
+        print("==", platform.python_implementation(), *sys.version.split())
+        print("==  ", platform.platform(aliased=True),
+                      "%s-endian" % sys.byteorder)
+        print("==  ", "hash algorithm:", sys.hash_info.algorithm,
+              "64bit" if sys.maxsize > 2**32 else "32bit")
+        print("==  ", os.getcwd())
+        print("Testing with flags:", sys.flags)
+
+    # if testdir is set, then we are not running the python tests suite, so
+    # don't add default tests to be executed or skipped (pass empty values)
+    if ns.testdir:
+        alltests = findtests(ns.testdir, list(), set())
+    else:
+        alltests = findtests(ns.testdir, stdtests, nottests)
+
+    selected = tests or ns.args or alltests
+    if ns.single:
+        selected = selected[:1]
+        try:
+            next_single_test = alltests[alltests.index(selected[0])+1]
+        except IndexError:
+            next_single_test = None
+    # Remove all the selected tests that precede start if it's set.
+    if ns.start:
+        try:
+            del selected[:selected.index(ns.start)]
+        except ValueError:
+            print("Couldn't find starting test (%s), using all tests" % ns.start)
+    if ns.randomize:
+        if ns.random_seed is None:
+            ns.random_seed = random.randrange(10000000)
+        random.seed(ns.random_seed)
+        print("Using random seed", ns.random_seed)
+        random.shuffle(selected)
+    if ns.trace:
+        import trace, tempfile
+        tracer = trace.Trace(ignoredirs=[sys.base_prefix, sys.base_exec_prefix,
+                                         tempfile.gettempdir()],
+                             trace=False, count=True)
+
+    test_times = []
+    support.verbose = ns.verbose      # Tell tests to be moderately quiet
+    support.use_resources = ns.use_resources
+    save_modules = sys.modules.keys()
+
+    def accumulate_result(test, result):
+        ok, test_time = result
+        test_times.append((test_time, test))
+        if ok == PASSED:
+            good.append(test)
+        elif ok == FAILED:
+            bad.append(test)
+        elif ok == ENV_CHANGED:
+            environment_changed.append(test)
+        elif ok == SKIPPED:
+            skipped.append(test)
+        elif ok == RESOURCE_DENIED:
+            skipped.append(test)
+            resource_denieds.append(test)
+
+    if ns.forever:
+        def test_forever(tests=list(selected)):
+            while True:
+                for test in tests:
+                    yield test
+                    if bad:
+                        return
+        tests = test_forever()
+        test_count = ''
+        test_count_width = 3
+    else:
+        tests = iter(selected)
+        test_count = '/{}'.format(len(selected))
+        test_count_width = len(test_count) - 1
+
+    if ns.use_mp:
+        try:
+            from threading import Thread
+        except ImportError:
+            print("Multiprocess option requires thread support")
+            sys.exit(2)
+        from queue import Queue
+        debug_output_pat = re.compile(r"\[\d+ refs, \d+ blocks\]$")
+        output = Queue()
+        pending = MultiprocessTests(tests)
+        def work():
+            # A worker thread.
+            try:
+                while True:
+                    try:
+                        test = next(pending)
+                    except StopIteration:
+                        output.put((None, None, None, None))
+                        return
+                    retcode, stdout, stderr = run_test_in_subprocess(test, ns)
+                    # Strip last refcount output line if it exists, since it
+                    # comes from the shutdown of the interpreter in the subcommand.
+                    stderr = debug_output_pat.sub("", stderr)
+                    stdout, _, result = stdout.strip().rpartition("\n")
+                    if retcode != 0:
+                        result = (CHILD_ERROR, "Exit code %s" % retcode)
+                        output.put((test, stdout.rstrip(), stderr.rstrip(), result))
+                        return
+                    if not result:
+                        output.put((None, None, None, None))
+                        return
+                    result = json.loads(result)
+                    output.put((test, stdout.rstrip(), stderr.rstrip(), result))
+            except BaseException:
+                output.put((None, None, None, None))
+                raise
+        workers = [Thread(target=work) for i in range(ns.use_mp)]
+        for worker in workers:
+            worker.start()
+        finished = 0
+        test_index = 1
+        try:
+            while finished < ns.use_mp:
+                test, stdout, stderr, result = output.get()
+                if test is None:
+                    finished += 1
+                    continue
+                accumulate_result(test, result)
+                if not ns.quiet:
+                    fmt = "[{1:{0}}{2}/{3}] {4}" if bad else "[{1:{0}}{2}] {4}"
+                    print(fmt.format(
+                        test_count_width, test_index, test_count,
+                        len(bad), test))
+                if stdout:
+                    print(stdout)
+                if stderr:
+                    print(stderr, file=sys.stderr)
+                sys.stdout.flush()
+                sys.stderr.flush()
+                if result[0] == INTERRUPTED:
+                    raise KeyboardInterrupt
+                if result[0] == CHILD_ERROR:
+                    raise Exception("Child error on {}: {}".format(test, result[1]))
+                test_index += 1
+        except KeyboardInterrupt:
+            interrupted = True
+            pending.interrupted = True
+        for worker in workers:
+            worker.join()
+    else:
+        for test_index, test in enumerate(tests, 1):
+            if not ns.quiet:
+                fmt = "[{1:{0}}{2}/{3}] {4}" if bad else "[{1:{0}}{2}] {4}"
+                print(fmt.format(
+                    test_count_width, test_index, test_count, len(bad), test))
+                sys.stdout.flush()
+            if ns.trace:
+                # If we're tracing code coverage, then we don't exit with status
+                # if on a false return value from main.
+                tracer.runctx('runtest(test, ns.verbose, ns.quiet, timeout=ns.timeout)',
+                              globals=globals(), locals=vars())
+            else:
+                try:
+                    result = runtest(test, ns.verbose, ns.quiet,
+                                     ns.huntrleaks,
+                                     output_on_failure=ns.verbose3,
+                                     timeout=ns.timeout, failfast=ns.failfast,
+                                     match_tests=ns.match_tests)
+                    accumulate_result(test, result)
+                except KeyboardInterrupt:
+                    interrupted = True
+                    break
+            if ns.findleaks:
+                gc.collect()
+                if gc.garbage:
+                    print("Warning: test created", len(gc.garbage), end=' ')
+                    print("uncollectable object(s).")
+                    # move the uncollectable objects somewhere so we don't see
+                    # them again
+                    found_garbage.extend(gc.garbage)
+                    del gc.garbage[:]
+            # Unload the newly imported modules (best effort finalization)
+            for module in sys.modules.keys():
+                if module not in save_modules and module.startswith("test."):
+                    support.unload(module)
+
+    if interrupted:
+        # print a newline after ^C
+        print()
+        print("Test suite interrupted by signal SIGINT.")
+        omitted = set(selected) - set(good) - set(bad) - set(skipped)
+        print(count(len(omitted), "test"), "omitted:")
+        printlist(omitted)
+    if good and not ns.quiet:
+        if not bad and not skipped and not interrupted and len(good) > 1:
+            print("All", end=' ')
+        print(count(len(good), "test"), "OK.")
+    if ns.print_slow:
+        test_times.sort(reverse=True)
+        print("10 slowest tests:")
+        for time, test in test_times[:10]:
+            print("%s: %.1fs" % (test, time))
+    if bad:
+        print(count(len(bad), "test"), "failed:")
+        printlist(bad)
+    if environment_changed:
+        print("{} altered the execution environment:".format(
+                 count(len(environment_changed), "test")))
+        printlist(environment_changed)
+    if skipped and not ns.quiet:
+        print(count(len(skipped), "test"), "skipped:")
+        printlist(skipped)
+
+    if ns.verbose2 and bad:
+        print("Re-running failed tests in verbose mode")
+        for test in bad[:]:
+            print("Re-running test %r in verbose mode" % test)
+            sys.stdout.flush()
+            try:
+                ns.verbose = True
+                ok = runtest(test, True, ns.quiet, ns.huntrleaks,
+                             timeout=ns.timeout)
+            except KeyboardInterrupt:
+                # print a newline separate from the ^C
+                print()
+                break
+            else:
+                if ok[0] in {PASSED, ENV_CHANGED, SKIPPED, RESOURCE_DENIED}:
+                    bad.remove(test)
+        else:
+            if bad:
+                print(count(len(bad), 'test'), "failed again:")
+                printlist(bad)
+
+    if ns.single:
+        if next_single_test:
+            with open(filename, 'w') as fp:
+                fp.write(next_single_test + '\n')
+        else:
+            os.unlink(filename)
+
+    if ns.trace:
+        r = tracer.results()
+        r.write_results(show_missing=True, summary=True, coverdir=ns.coverdir)
+
+    if ns.runleaks:
+        os.system("leaks %d" % os.getpid())
+
+    sys.exit(len(bad) > 0 or interrupted)
+
+
+# We do not use a generator so multiple threads can call next().
+class MultiprocessTests(object):
+
+    """A thread-safe iterator over tests for multiprocess mode."""
+
+    def __init__(self, tests):
+        self.interrupted = False
+        self.lock = threading.Lock()
+        self.tests = tests
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        with self.lock:
+            if self.interrupted:
+                raise StopIteration('tests interrupted')
+            return next(self.tests)
+
+
+def replace_stdout():
+    """Set stdout encoder error handler to backslashreplace (as stderr error
+    handler) to avoid UnicodeEncodeError when printing a traceback"""
+    import atexit
+
+    stdout = sys.stdout
+    sys.stdout = open(stdout.fileno(), 'w',
+        encoding=stdout.encoding,
+        errors="backslashreplace",
+        closefd=False,
+        newline='\n')
+
+    def restore_stdout():
+        sys.stdout.close()
+        sys.stdout = stdout
+    atexit.register(restore_stdout)
+
+
+def removepy(names):
+    if not names:
+        return
+    for idx, name in enumerate(names):
+        basename, ext = os.path.splitext(name)
+        if ext == '.py':
+            names[idx] = basename
+
+
+def count(n, word):
+    if n == 1:
+        return "%d %s" % (n, word)
+    else:
+        return "%d %ss" % (n, word)
+
+
+def printlist(x, width=70, indent=4):
+    """Print the elements of iterable x to stdout.
+
+    Optional arg width (default 70) is the maximum line length.
+    Optional arg indent (default 4) is the number of blanks with which to
+    begin each line.
+    """
+
+    from textwrap import fill
+    blanks = ' ' * indent
+    # Print the sorted list: 'x' may be a '--random' list or a set()
+    print(fill(' '.join(str(elt) for elt in sorted(x)), width,
+               initial_indent=blanks, subsequent_indent=blanks))
+
+
+def main_in_temp_cwd():
+    """Run main() in a temporary working directory."""
+    if sysconfig.is_python_build():
+        try:
+            os.mkdir(TEMPDIR)
+        except FileExistsError:
+            pass
+
+    # Define a writable temp dir that will be used as cwd while running
+    # the tests. The name of the dir includes the pid to allow parallel
+    # testing (see the -j option).
+    test_cwd = 'test_python_{}'.format(os.getpid())
+    test_cwd = os.path.join(TEMPDIR, test_cwd)
+
+    # Run the tests in a context manager that temporarily changes the CWD to a
+    # temporary and writable directory.  If it's not possible to create or
+    # change the CWD, the original CWD will be used.  The original CWD is
+    # available from support.SAVEDCWD.
+    with support.temp_cwd(test_cwd, quiet=True):
+        main()

Lib/test/libregrtest/refleak.py

@@ -0,0 +1,165 @@
+import os
+import re
+import sys
+import warnings
+from inspect import isabstract
+from test import support
+
+
+def dash_R(the_module, test, indirect_test, huntrleaks):
+    """Run a test multiple times, looking for reference leaks.
+
+    Returns:
+        False if the test didn't leak references; True if we detected refleaks.
+    """
+    # This code is hackish and inelegant, but it seems to do the job.
+    import copyreg
+    import collections.abc
+
+    if not hasattr(sys, 'gettotalrefcount'):
+        raise Exception("Tracking reference leaks requires a debug build "
+                        "of Python")
+
+    # Save current values for dash_R_cleanup() to restore.
+    fs = warnings.filters[:]
+    ps = copyreg.dispatch_table.copy()
+    pic = sys.path_importer_cache.copy()
+    try:
+        import zipimport
+    except ImportError:
+        zdc = None # Run unmodified on platforms without zipimport support
+    else:
+        zdc = zipimport._zip_directory_cache.copy()
+    abcs = {}
+    for abc in [getattr(collections.abc, a) for a in collections.abc.__all__]:
+        if not isabstract(abc):
+            continue
+        for obj in abc.__subclasses__() + [abc]:
+            abcs[obj] = obj._abc_registry.copy()
+
+    nwarmup, ntracked, fname = huntrleaks
+    fname = os.path.join(support.SAVEDCWD, fname)
+    repcount = nwarmup + ntracked
+    rc_deltas = [0] * repcount
+    alloc_deltas = [0] * repcount
+
+    print("beginning", repcount, "repetitions", file=sys.stderr)
+    print(("1234567890"*(repcount//10 + 1))[:repcount], file=sys.stderr)
+    sys.stderr.flush()
+    for i in range(repcount):
+        indirect_test()
+        alloc_after, rc_after = dash_R_cleanup(fs, ps, pic, zdc, abcs)
+        sys.stderr.write('.')
+        sys.stderr.flush()
+        if i >= nwarmup:
+            rc_deltas[i] = rc_after - rc_before
+            alloc_deltas[i] = alloc_after - alloc_before
+        alloc_before, rc_before = alloc_after, rc_after
+    print(file=sys.stderr)
+    # These checkers return False on success, True on failure
+    def check_rc_deltas(deltas):
+        return any(deltas)
+    def check_alloc_deltas(deltas):
+        # At least 1/3rd of 0s
+        if 3 * deltas.count(0) < len(deltas):
+            return True
+        # Nothing else than 1s, 0s and -1s
+        if not set(deltas) <= {1,0,-1}:
+            return True
+        return False
+    failed = False
+    for deltas, item_name, checker in [
+        (rc_deltas, 'references', check_rc_deltas),
+        (alloc_deltas, 'memory blocks', check_alloc_deltas)]:
+        if checker(deltas):
+            msg = '%s leaked %s %s, sum=%s' % (
+                test, deltas[nwarmup:], item_name, sum(deltas))
+            print(msg, file=sys.stderr)
+            sys.stderr.flush()
+            with open(fname, "a") as refrep:
+                print(msg, file=refrep)
+                refrep.flush()
+            failed = True
+    return failed
+
+
+def dash_R_cleanup(fs, ps, pic, zdc, abcs):
+    import gc, copyreg
+    import _strptime, linecache
+    import urllib.parse, urllib.request, mimetypes, doctest
+    import struct, filecmp, collections.abc
+    from distutils.dir_util import _path_created
+    from weakref import WeakSet
+
+    # Clear the warnings registry, so they can be displayed again
+    for mod in sys.modules.values():
+        if hasattr(mod, '__warningregistry__'):
+            del mod.__warningregistry__
+
+    # Restore some original values.
+    warnings.filters[:] = fs
+    copyreg.dispatch_table.clear()
+    copyreg.dispatch_table.update(ps)
+    sys.path_importer_cache.clear()
+    sys.path_importer_cache.update(pic)
+    try:
+        import zipimport
+    except ImportError:
+        pass # Run unmodified on platforms without zipimport support
+    else:
+        zipimport._zip_directory_cache.clear()
+        zipimport._zip_directory_cache.update(zdc)
+
+    # clear type cache
+    sys._clear_type_cache()
+
+    # Clear ABC registries, restoring previously saved ABC registries.
+    for abc in [getattr(collections.abc, a) for a in collections.abc.__all__]:
+        if not isabstract(abc):
+            continue
+        for obj in abc.__subclasses__() + [abc]:
+            obj._abc_registry = abcs.get(obj, WeakSet()).copy()
+            obj._abc_cache.clear()
+            obj._abc_negative_cache.clear()
+
+    # Flush standard output, so that buffered data is sent to the OS and
+    # associated Python objects are reclaimed.
+    for stream in (sys.stdout, sys.stderr, sys.__stdout__, sys.__stderr__):
+        if stream is not None:
+            stream.flush()
+
+    # Clear assorted module caches.
+    _path_created.clear()
+    re.purge()
+    _strptime._regex_cache.clear()
+    urllib.parse.clear_cache()
+    urllib.request.urlcleanup()
+    linecache.clearcache()
+    mimetypes._default_mime_types()
+    filecmp._cache.clear()
+    struct._clearcache()
+    doctest.master = None
+    try:
+        import ctypes
+    except ImportError:
+        # Don't worry about resetting the cache if ctypes is not supported
+        pass
+    else:
+        ctypes._reset_cache()
+
+    # Collect cyclic trash and read memory statistics immediately after.
+    func1 = sys.getallocatedblocks
+    func2 = sys.gettotalrefcount
+    gc.collect()
+    return func1(), func2()
+
+
+def warm_caches():
+    # char cache
+    s = bytes(range(256))
+    for i in range(256):
+        s[i:i+1]
+    # unicode cache
+    x = [chr(i) for i in range(256)]
+    # int cache
+    x = list(range(-5, 257))

Lib/test/libregrtest/runtest.py

@@ -0,0 +1,271 @@
+import faulthandler
+import importlib
+import io
+import json
+import os
+import sys
+import time
+import traceback
+import unittest
+from test import support
+from test.libregrtest.refleak import dash_R
+from test.libregrtest.save_env import saved_test_environment
+
+
+# Test result constants.
+PASSED = 1
+FAILED = 0
+ENV_CHANGED = -1
+SKIPPED = -2
+RESOURCE_DENIED = -3
+INTERRUPTED = -4
+CHILD_ERROR = -5   # error in a child process
+
+
+def run_test_in_subprocess(testname, ns):
+    """Run the given test in a subprocess with --slaveargs.
+
+    ns is the option Namespace parsed from command-line arguments. regrtest
+    is invoked in a subprocess with the --slaveargs argument; when the
+    subprocess exits, its return code, stdout and stderr are returned as a
+    3-tuple.
+    """
+    from subprocess import Popen, PIPE
+    base_cmd = ([sys.executable] + support.args_from_interpreter_flags() +
+                ['-X', 'faulthandler', '-m', 'test.regrtest'])
+
+    slaveargs = (
+            (testname, ns.verbose, ns.quiet),
+            dict(huntrleaks=ns.huntrleaks,
+                 use_resources=ns.use_resources,
+                 output_on_failure=ns.verbose3,
+                 timeout=ns.timeout, failfast=ns.failfast,
+                 match_tests=ns.match_tests))
+    # Running the child from the same working directory as regrtest's original
+    # invocation ensures that TEMPDIR for the child is the same when
+    # sysconfig.is_python_build() is true. See issue 15300.
+    popen = Popen(base_cmd + ['--slaveargs', json.dumps(slaveargs)],
+                  stdout=PIPE, stderr=PIPE,
+                  universal_newlines=True,
+                  close_fds=(os.name != 'nt'),
+                  cwd=support.SAVEDCWD)
+    stdout, stderr = popen.communicate()
+    retcode = popen.wait()
+    return retcode, stdout, stderr
+
+
+# small set of tests to determine if we have a basically functioning interpreter
+# (i.e. if any of these fail, then anything else is likely to follow)
+STDTESTS = [
+    'test_grammar',
+    'test_opcodes',
+    'test_dict',
+    'test_builtin',
+    'test_exceptions',
+    'test_types',
+    'test_unittest',
+    'test_doctest',
+    'test_doctest2',
+    'test_support'
+]
+
+# set of tests that we don't want to be executed when using regrtest
+NOTTESTS = set()
+
+
+def findtests(testdir=None, stdtests=STDTESTS, nottests=NOTTESTS):
+    """Return a list of all applicable test modules."""
+    testdir = findtestdir(testdir)
+    names = os.listdir(testdir)
+    tests = []
+    others = set(stdtests) | nottests
+    for name in names:
+        mod, ext = os.path.splitext(name)
+        if mod[:5] == "test_" and ext in (".py", "") and mod not in others:
+            tests.append(mod)
+    return stdtests + sorted(tests)
+
+
+def runtest(test, verbose, quiet,
+            huntrleaks=False, use_resources=None,
+            output_on_failure=False, failfast=False, match_tests=None,
+            timeout=None):
+    """Run a single test.
+
+    test -- the name of the test
+    verbose -- if true, print more messages
+    quiet -- if true, don't print 'skipped' messages (probably redundant)
+    huntrleaks -- run multiple times to test for leaks; requires a debug
+                  build; a triple corresponding to -R's three arguments
+    use_resources -- list of extra resources to use
+    output_on_failure -- if true, display test output on failure
+    timeout -- dump the traceback and exit if a test takes more than
+               timeout seconds
+    failfast, match_tests -- See regrtest command-line flags for these.
+
+    Returns the tuple result, test_time, where result is one of the constants:
+        INTERRUPTED      KeyboardInterrupt when run under -j
+        RESOURCE_DENIED  test skipped because resource denied
+        SKIPPED          test skipped for some other reason
+        ENV_CHANGED      test failed because it changed the execution environment
+        FAILED           test failed
+        PASSED           test passed
+    """
+
+    if use_resources is not None:
+        support.use_resources = use_resources
+    use_timeout = (timeout is not None)
+    if use_timeout:
+        faulthandler.dump_traceback_later(timeout, exit=True)
+    try:
+        support.match_tests = match_tests
+        if failfast:
+            support.failfast = True
+        if output_on_failure:
+            support.verbose = True
+
+            # Reuse the same instance to all calls to runtest(). Some
+            # tests keep a reference to sys.stdout or sys.stderr
+            # (eg. test_argparse).
+            if runtest.stringio is None:
+                stream = io.StringIO()
+                runtest.stringio = stream
+            else:
+                stream = runtest.stringio
+                stream.seek(0)
+                stream.truncate()
+
+            orig_stdout = sys.stdout
+            orig_stderr = sys.stderr
+            try:
+                sys.stdout = stream
+                sys.stderr = stream
+                result = runtest_inner(test, verbose, quiet, huntrleaks,
+                                       display_failure=False)
+                if result[0] == FAILED:
+                    output = stream.getvalue()
+                    orig_stderr.write(output)
+                    orig_stderr.flush()
+            finally:
+                sys.stdout = orig_stdout
+                sys.stderr = orig_stderr
+        else:
+            support.verbose = verbose  # Tell tests to be moderately quiet
+            result = runtest_inner(test, verbose, quiet, huntrleaks,
+                                   display_failure=not verbose)
+        return result
+    finally:
+        if use_timeout:
+            faulthandler.cancel_dump_traceback_later()
+        cleanup_test_droppings(test, verbose)
+runtest.stringio = None
+
+
+def runtest_inner(test, verbose, quiet,
+                  huntrleaks=False, display_failure=True):
+    support.unload(test)
+
+    test_time = 0.0
+    refleak = False  # True if the test leaked references.
+    try:
+        if test.startswith('test.'):
+            abstest = test
+        else:
+            # Always import it from the test package
+            abstest = 'test.' + test
+        with saved_test_environment(test, verbose, quiet) as environment:
+            start_time = time.time()
+            the_module = importlib.import_module(abstest)
+            # If the test has a test_main, that will run the appropriate
+            # tests.  If not, use normal unittest test loading.
+            test_runner = getattr(the_module, "test_main", None)
+            if test_runner is None:
+                def test_runner():
+                    loader = unittest.TestLoader()
+                    tests = loader.loadTestsFromModule(the_module)
+                    for error in loader.errors:
+                        print(error, file=sys.stderr)
+                    if loader.errors:
+                        raise Exception("errors while loading tests")
+                    support.run_unittest(tests)
+            test_runner()
+            if huntrleaks:
+                refleak = dash_R(the_module, test, test_runner, huntrleaks)
+            test_time = time.time() - start_time
+    except support.ResourceDenied as msg:
+        if not quiet:
+            print(test, "skipped --", msg)
+            sys.stdout.flush()
+        return RESOURCE_DENIED, test_time
+    except unittest.SkipTest as msg:
+        if not quiet:
+            print(test, "skipped --", msg)
+            sys.stdout.flush()
+        return SKIPPED, test_time
+    except KeyboardInterrupt:
+        raise
+    except support.TestFailed as msg:
+        if display_failure:
+            print("test", test, "failed --", msg, file=sys.stderr)
+        else:
+            print("test", test, "failed", file=sys.stderr)
+        sys.stderr.flush()
+        return FAILED, test_time
+    except:
+        msg = traceback.format_exc()
+        print("test", test, "crashed --", msg, file=sys.stderr)
+        sys.stderr.flush()
+        return FAILED, test_time
+    else:
+        if refleak:
+            return FAILED, test_time
+        if environment.changed:
+            return ENV_CHANGED, test_time
+        return PASSED, test_time
+
+
+def cleanup_test_droppings(testname, verbose):
+    import shutil
+    import stat
+    import gc
+
+    # First kill any dangling references to open files etc.
+    # This can also issue some ResourceWarnings which would otherwise get
+    # triggered during the following test run, and possibly produce failures.
+    gc.collect()
+
+    # Try to clean up junk commonly left behind.  While tests shouldn't leave
+    # any files or directories behind, when a test fails that can be tedious
+    # for it to arrange.  The consequences can be especially nasty on Windows,
+    # since if a test leaves a file open, it cannot be deleted by name (while
+    # there's nothing we can do about that here either, we can display the
+    # name of the offending test, which is a real help).
+    for name in (support.TESTFN,
+                 "db_home",
+                ):
+        if not os.path.exists(name):
+            continue
+
+        if os.path.isdir(name):
+            kind, nuker = "directory", shutil.rmtree
+        elif os.path.isfile(name):
+            kind, nuker = "file", os.unlink
+        else:
+            raise SystemError("os.path says %r exists but is neither "
+                              "directory nor file" % name)
+
+        if verbose:
+            print("%r left behind %s %r" % (testname, kind, name))
+        try:
+            # if we have chmod, fix possible permissions problems
+            # that might prevent cleanup
+            if (hasattr(os, 'chmod')):
+                os.chmod(name, stat.S_IRWXU | stat.S_IRWXG | stat.S_IRWXO)
+            nuker(name)
+        except Exception as msg:
+            print(("%r left behind %s %r and it couldn't be "
+                "removed: %s" % (testname, kind, name, msg)), file=sys.stderr)
+
+
+def findtestdir(path=None):
+    return path or os.path.dirname(os.path.dirname(__file__)) or os.curdir

Lib/test/libregrtest/save_env.py

@@ -0,0 +1,284 @@
+import builtins
+import locale
+import logging
+import os
+import shutil
+import sys
+import sysconfig
+import warnings
+from test import support
+try:
+    import threading
+except ImportError:
+    threading = None
+try:
+    import _multiprocessing, multiprocessing.process
+except ImportError:
+    multiprocessing = None
+
+
+# Unit tests are supposed to leave the execution environment unchanged
+# once they complete.  But sometimes tests have bugs, especially when
+# tests fail, and the changes to environment go on to mess up other
+# tests.  This can cause issues with buildbot stability, since tests
+# are run in random order and so problems may appear to come and go.
+# There are a few things we can save and restore to mitigate this, and
+# the following context manager handles this task.
+
+class saved_test_environment:
+    """Save bits of the test environment and restore them at block exit.
+
+        with saved_test_environment(testname, verbose, quiet):
+            #stuff
+
+    Unless quiet is True, a warning is printed to stderr if any of
+    the saved items was changed by the test.  The attribute 'changed'
+    is initially False, but is set to True if a change is detected.
+
+    If verbose is more than 1, the before and after state of changed
+    items is also printed.
+    """
+
+    changed = False
+
+    def __init__(self, testname, verbose=0, quiet=False):
+        self.testname = testname
+        self.verbose = verbose
+        self.quiet = quiet
+
+    # To add things to save and restore, add a name XXX to the resources list
+    # and add corresponding get_XXX/restore_XXX functions.  get_XXX should
+    # return the value to be saved and compared against a second call to the
+    # get function when test execution completes.  restore_XXX should accept
+    # the saved value and restore the resource using it.  It will be called if
+    # and only if a change in the value is detected.
+    #
+    # Note: XXX will have any '.' replaced with '_' characters when determining
+    # the corresponding method names.
+
+    resources = ('sys.argv', 'cwd', 'sys.stdin', 'sys.stdout', 'sys.stderr',
+                 'os.environ', 'sys.path', 'sys.path_hooks', '__import__',
+                 'warnings.filters', 'asyncore.socket_map',
+                 'logging._handlers', 'logging._handlerList', 'sys.gettrace',
+                 'sys.warnoptions',
+                 # multiprocessing.process._cleanup() may release ref
+                 # to a thread, so check processes first.
+                 'multiprocessing.process._dangling', 'threading._dangling',
+                 'sysconfig._CONFIG_VARS', 'sysconfig._INSTALL_SCHEMES',
+                 'files', 'locale', 'warnings.showwarning',
+                )
+
+    def get_sys_argv(self):
+        return id(sys.argv), sys.argv, sys.argv[:]
+    def restore_sys_argv(self, saved_argv):
+        sys.argv = saved_argv[1]
+        sys.argv[:] = saved_argv[2]
+
+    def get_cwd(self):
+        return os.getcwd()
+    def restore_cwd(self, saved_cwd):
+        os.chdir(saved_cwd)
+
+    def get_sys_stdout(self):
+        return sys.stdout
+    def restore_sys_stdout(self, saved_stdout):
+        sys.stdout = saved_stdout
+
+    def get_sys_stderr(self):
+        return sys.stderr
+    def restore_sys_stderr(self, saved_stderr):
+        sys.stderr = saved_stderr
+
+    def get_sys_stdin(self):
+        return sys.stdin
+    def restore_sys_stdin(self, saved_stdin):
+        sys.stdin = saved_stdin
+
+    def get_os_environ(self):
+        return id(os.environ), os.environ, dict(os.environ)
+    def restore_os_environ(self, saved_environ):
+        os.environ = saved_environ[1]
+        os.environ.clear()
+        os.environ.update(saved_environ[2])
+
+    def get_sys_path(self):
+        return id(sys.path), sys.path, sys.path[:]
+    def restore_sys_path(self, saved_path):
+        sys.path = saved_path[1]
+        sys.path[:] = saved_path[2]
+
+    def get_sys_path_hooks(self):
+        return id(sys.path_hooks), sys.path_hooks, sys.path_hooks[:]
+    def restore_sys_path_hooks(self, saved_hooks):
+        sys.path_hooks = saved_hooks[1]
+        sys.path_hooks[:] = saved_hooks[2]
+
+    def get_sys_gettrace(self):
+        return sys.gettrace()
+    def restore_sys_gettrace(self, trace_fxn):
+        sys.settrace(trace_fxn)
+
+    def get___import__(self):
+        return builtins.__import__
+    def restore___import__(self, import_):
+        builtins.__import__ = import_
+
+    def get_warnings_filters(self):
+        return id(warnings.filters), warnings.filters, warnings.filters[:]
+    def restore_warnings_filters(self, saved_filters):
+        warnings.filters = saved_filters[1]
+        warnings.filters[:] = saved_filters[2]
+
+    def get_asyncore_socket_map(self):
+        asyncore = sys.modules.get('asyncore')
+        # XXX Making a copy keeps objects alive until __exit__ gets called.
+        return asyncore and asyncore.socket_map.copy() or {}
+    def restore_asyncore_socket_map(self, saved_map):
+        asyncore = sys.modules.get('asyncore')
+        if asyncore is not None:
+            asyncore.close_all(ignore_all=True)
+            asyncore.socket_map.update(saved_map)
+
+    def get_shutil_archive_formats(self):
+        # we could call get_archives_formats() but that only returns the
+        # registry keys; we want to check the values too (the functions that
+        # are registered)
+        return shutil._ARCHIVE_FORMATS, shutil._ARCHIVE_FORMATS.copy()
+    def restore_shutil_archive_formats(self, saved):
+        shutil._ARCHIVE_FORMATS = saved[0]
+        shutil._ARCHIVE_FORMATS.clear()
+        shutil._ARCHIVE_FORMATS.update(saved[1])
+
+    def get_shutil_unpack_formats(self):
+        return shutil._UNPACK_FORMATS, shutil._UNPACK_FORMATS.copy()
+    def restore_shutil_unpack_formats(self, saved):
+        shutil._UNPACK_FORMATS = saved[0]
+        shutil._UNPACK_FORMATS.clear()
+        shutil._UNPACK_FORMATS.update(saved[1])
+
+    def get_logging__handlers(self):
+        # _handlers is a WeakValueDictionary
+        return id(logging._handlers), logging._handlers, logging._handlers.copy()
+    def restore_logging__handlers(self, saved_handlers):
+        # Can't easily revert the logging state
+        pass
+
+    def get_logging__handlerList(self):
+        # _handlerList is a list of weakrefs to handlers
+        return id(logging._handlerList), logging._handlerList, logging._handlerList[:]
+    def restore_logging__handlerList(self, saved_handlerList):
+        # Can't easily revert the logging state
+        pass
+
+    def get_sys_warnoptions(self):
+        return id(sys.warnoptions), sys.warnoptions, sys.warnoptions[:]
+    def restore_sys_warnoptions(self, saved_options):
+        sys.warnoptions = saved_options[1]
+        sys.warnoptions[:] = saved_options[2]
+
+    # Controlling dangling references to Thread objects can make it easier
+    # to track reference leaks.
+    def get_threading__dangling(self):
+        if not threading:
+            return None
+        # This copies the weakrefs without making any strong reference
+        return threading._dangling.copy()
+    def restore_threading__dangling(self, saved):
+        if not threading:
+            return
+        threading._dangling.clear()
+        threading._dangling.update(saved)
+
+    # Same for Process objects
+    def get_multiprocessing_process__dangling(self):
+        if not multiprocessing:
+            return None
+        # Unjoined process objects can survive after process exits
+        multiprocessing.process._cleanup()
+        # This copies the weakrefs without making any strong reference
+        return multiprocessing.process._dangling.copy()
+    def restore_multiprocessing_process__dangling(self, saved):
+        if not multiprocessing:
+            return
+        multiprocessing.process._dangling.clear()
+        multiprocessing.process._dangling.update(saved)
+
+    def get_sysconfig__CONFIG_VARS(self):
+        # make sure the dict is initialized
+        sysconfig.get_config_var('prefix')
+        return (id(sysconfig._CONFIG_VARS), sysconfig._CONFIG_VARS,
+                dict(sysconfig._CONFIG_VARS))
+    def restore_sysconfig__CONFIG_VARS(self, saved):
+        sysconfig._CONFIG_VARS = saved[1]
+        sysconfig._CONFIG_VARS.clear()
+        sysconfig._CONFIG_VARS.update(saved[2])
+
+    def get_sysconfig__INSTALL_SCHEMES(self):
+        return (id(sysconfig._INSTALL_SCHEMES), sysconfig._INSTALL_SCHEMES,
+                sysconfig._INSTALL_SCHEMES.copy())
+    def restore_sysconfig__INSTALL_SCHEMES(self, saved):
+        sysconfig._INSTALL_SCHEMES = saved[1]
+        sysconfig._INSTALL_SCHEMES.clear()
+        sysconfig._INSTALL_SCHEMES.update(saved[2])
+
+    def get_files(self):
+        return sorted(fn + ('/' if os.path.isdir(fn) else '')
+                      for fn in os.listdir())
+    def restore_files(self, saved_value):
+        fn = support.TESTFN
+        if fn not in saved_value and (fn + '/') not in saved_value:
+            if os.path.isfile(fn):
+                support.unlink(fn)
+            elif os.path.isdir(fn):
+                support.rmtree(fn)
+
+    _lc = [getattr(locale, lc) for lc in dir(locale)
+           if lc.startswith('LC_')]
+    def get_locale(self):
+        pairings = []
+        for lc in self._lc:
+            try:
+                pairings.append((lc, locale.setlocale(lc, None)))
+            except (TypeError, ValueError):
+                continue
+        return pairings
+    def restore_locale(self, saved):
+        for lc, setting in saved:
+            locale.setlocale(lc, setting)
+
+    def get_warnings_showwarning(self):
+        return warnings.showwarning
+    def restore_warnings_showwarning(self, fxn):
+        warnings.showwarning = fxn
+
+    def resource_info(self):
+        for name in self.resources:
+            method_suffix = name.replace('.', '_')
+            get_name = 'get_' + method_suffix
+            restore_name = 'restore_' + method_suffix
+            yield name, getattr(self, get_name), getattr(self, restore_name)
+
+    def __enter__(self):
+        self.saved_values = dict((name, get()) for name, get, restore
+                                                   in self.resource_info())
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        saved_values = self.saved_values
+        del self.saved_values
+        for name, get, restore in self.resource_info():
+            current = get()
+            original = saved_values.pop(name)
+            # Check for changes to the resource's value
+            if current != original:
+                self.changed = True
+                restore(original)
+                if not self.quiet:
+                    print("Warning -- {} was modified by {}".format(
+                                                 name, self.testname),
+                                                 file=sys.stderr)
+                    if self.verbose > 1:
+                        print("  Before: {}\n  After:  {} ".format(
+                                                  original, current),
+                                                  file=sys.stderr)
+        return False

Lib/test/test_regrtest.py

@@ -7,7 +7,8 @@
 import getopt
 import os.path
 import unittest
-from test import regrtest, support, libregrtest
+from test import libregrtest
+from test import support
 
 class ParseArgsTestCase(unittest.TestCase):
 
@@ -15,7 +16,7 @@ class ParseArgsTestCase(unittest.TestCase):
 
     def checkError(self, args, msg):
         with support.captured_stderr() as err, self.assertRaises(SystemExit):
-            regrtest._parse_args(args)
+            libregrtest._parse_args(args)
         self.assertIn(msg, err.getvalue())
 
     def test_help(self):
@@ -23,82 +24,82 @@ def test_help(self):
             with self.subTest(opt=opt):
                 with support.captured_stdout() as out, \
                      self.assertRaises(SystemExit):
-                    regrtest._parse_args([opt])
+                    libregrtest._parse_args([opt])
                 self.assertIn('Run Python regression tests.', out.getvalue())
 
     @unittest.skipUnless(hasattr(faulthandler, 'dump_traceback_later'),
                          "faulthandler.dump_traceback_later() required")
     def test_timeout(self):
-        ns = regrtest._parse_args(['--timeout', '4.2'])
+        ns = libregrtest._parse_args(['--timeout', '4.2'])
         self.assertEqual(ns.timeout, 4.2)
         self.checkError(['--timeout'], 'expected one argument')
         self.checkError(['--timeout', 'foo'], 'invalid float value')
 
     def test_wait(self):
-        ns = regrtest._parse_args(['--wait'])
+        ns = libregrtest._parse_args(['--wait'])
         self.assertTrue(ns.wait)
 
     def test_slaveargs(self):
-        ns = regrtest._parse_args(['--slaveargs', '[[], {}]'])
+        ns = libregrtest._parse_args(['--slaveargs', '[[], {}]'])
         self.assertEqual(ns.slaveargs, '[[], {}]')
         self.checkError(['--slaveargs'], 'expected one argument')
 
     def test_start(self):
         for opt in '-S', '--start':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, 'foo'])
+                ns = libregrtest._parse_args([opt, 'foo'])
                 self.assertEqual(ns.start, 'foo')
                 self.checkError([opt], 'expected one argument')
 
     def test_verbose(self):
-        ns = regrtest._parse_args(['-v'])
+        ns = libregrtest._parse_args(['-v'])
         self.assertEqual(ns.verbose, 1)
-        ns = regrtest._parse_args(['-vvv'])
+        ns = libregrtest._parse_args(['-vvv'])
         self.assertEqual(ns.verbose, 3)
-        ns = regrtest._parse_args(['--verbose'])
+        ns = libregrtest._parse_args(['--verbose'])
         self.assertEqual(ns.verbose, 1)
-        ns = regrtest._parse_args(['--verbose'] * 3)
+        ns = libregrtest._parse_args(['--verbose'] * 3)
         self.assertEqual(ns.verbose, 3)
-        ns = regrtest._parse_args([])
+        ns = libregrtest._parse_args([])
         self.assertEqual(ns.verbose, 0)
 
     def test_verbose2(self):
         for opt in '-w', '--verbose2':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.verbose2)
 
     def test_verbose3(self):
         for opt in '-W', '--verbose3':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.verbose3)
 
     def test_quiet(self):
         for opt in '-q', '--quiet':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.quiet)
                 self.assertEqual(ns.verbose, 0)
 
     def test_slow(self):
         for opt in '-o', '--slow':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.print_slow)
 
     def test_header(self):
-        ns = regrtest._parse_args(['--header'])
+        ns = libregrtest._parse_args(['--header'])
         self.assertTrue(ns.header)
 
     def test_randomize(self):
         for opt in '-r', '--randomize':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.randomize)
 
     def test_randseed(self):
-        ns = regrtest._parse_args(['--randseed', '12345'])
+        ns = libregrtest._parse_args(['--randseed', '12345'])
         self.assertEqual(ns.random_seed, 12345)
         self.assertTrue(ns.randomize)
         self.checkError(['--randseed'], 'expected one argument')
@@ -107,7 +108,7 @@ def test_randseed(self):
     def test_fromfile(self):
         for opt in '-f', '--fromfile':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, 'foo'])
+                ns = libregrtest._parse_args([opt, 'foo'])
                 self.assertEqual(ns.fromfile, 'foo')
                 self.checkError([opt], 'expected one argument')
                 self.checkError([opt, 'foo', '-s'], "don't go together")
@@ -115,42 +116,42 @@ def test_fromfile(self):
     def test_exclude(self):
         for opt in '-x', '--exclude':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.exclude)
 
     def test_single(self):
         for opt in '-s', '--single':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.single)
                 self.checkError([opt, '-f', 'foo'], "don't go together")
 
     def test_match(self):
         for opt in '-m', '--match':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, 'pattern'])
+                ns = libregrtest._parse_args([opt, 'pattern'])
                 self.assertEqual(ns.match_tests, 'pattern')
                 self.checkError([opt], 'expected one argument')
 
     def test_failfast(self):
         for opt in '-G', '--failfast':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, '-v'])
+                ns = libregrtest._parse_args([opt, '-v'])
                 self.assertTrue(ns.failfast)
-                ns = regrtest._parse_args([opt, '-W'])
+                ns = libregrtest._parse_args([opt, '-W'])
                 self.assertTrue(ns.failfast)
                 self.checkError([opt], '-G/--failfast needs either -v or -W')
 
     def test_use(self):
         for opt in '-u', '--use':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, 'gui,network'])
+                ns = libregrtest._parse_args([opt, 'gui,network'])
                 self.assertEqual(ns.use_resources, ['gui', 'network'])
-                ns = regrtest._parse_args([opt, 'gui,none,network'])
+                ns = libregrtest._parse_args([opt, 'gui,none,network'])
                 self.assertEqual(ns.use_resources, ['network'])
                 expected = list(libregrtest.RESOURCE_NAMES)
                 expected.remove('gui')
-                ns = regrtest._parse_args([opt, 'all,-gui'])
+                ns = libregrtest._parse_args([opt, 'all,-gui'])
                 self.assertEqual(ns.use_resources, expected)
                 self.checkError([opt], 'expected one argument')
                 self.checkError([opt, 'foo'], 'invalid resource')
@@ -158,31 +159,31 @@ def test_use(self):
     def test_memlimit(self):
         for opt in '-M', '--memlimit':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, '4G'])
+                ns = libregrtest._parse_args([opt, '4G'])
                 self.assertEqual(ns.memlimit, '4G')
                 self.checkError([opt], 'expected one argument')
 
     def test_testdir(self):
-        ns = regrtest._parse_args(['--testdir', 'foo'])
+        ns = libregrtest._parse_args(['--testdir', 'foo'])
         self.assertEqual(ns.testdir, os.path.join(support.SAVEDCWD, 'foo'))
         self.checkError(['--testdir'], 'expected one argument')
 
     def test_runleaks(self):
         for opt in '-L', '--runleaks':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.runleaks)
 
     def test_huntrleaks(self):
         for opt in '-R', '--huntrleaks':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, ':'])
+                ns = libregrtest._parse_args([opt, ':'])
                 self.assertEqual(ns.huntrleaks, (5, 4, 'reflog.txt'))
-                ns = regrtest._parse_args([opt, '6:'])
+                ns = libregrtest._parse_args([opt, '6:'])
                 self.assertEqual(ns.huntrleaks, (6, 4, 'reflog.txt'))
-                ns = regrtest._parse_args([opt, ':3'])
+                ns = libregrtest._parse_args([opt, ':3'])
                 self.assertEqual(ns.huntrleaks, (5, 3, 'reflog.txt'))
-                ns = regrtest._parse_args([opt, '6:3:leaks.log'])
+                ns = libregrtest._parse_args([opt, '6:3:leaks.log'])
                 self.assertEqual(ns.huntrleaks, (6, 3, 'leaks.log'))
                 self.checkError([opt], 'expected one argument')
                 self.checkError([opt, '6'],
@@ -193,7 +194,7 @@ def test_huntrleaks(self):
     def test_multiprocess(self):
         for opt in '-j', '--multiprocess':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, '2'])
+                ns = libregrtest._parse_args([opt, '2'])
                 self.assertEqual(ns.use_mp, 2)
                 self.checkError([opt], 'expected one argument')
                 self.checkError([opt, 'foo'], 'invalid int value')
@@ -204,13 +205,13 @@ def test_multiprocess(self):
     def test_coverage(self):
         for opt in '-T', '--coverage':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.trace)
 
     def test_coverdir(self):
         for opt in '-D', '--coverdir':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, 'foo'])
+                ns = libregrtest._parse_args([opt, 'foo'])
                 self.assertEqual(ns.coverdir,
                                  os.path.join(support.SAVEDCWD, 'foo'))
                 self.checkError([opt], 'expected one argument')
@@ -218,13 +219,13 @@ def test_coverdir(self):
     def test_nocoverdir(self):
         for opt in '-N', '--nocoverdir':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertIsNone(ns.coverdir)
 
     def test_threshold(self):
         for opt in '-t', '--threshold':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt, '1000'])
+                ns = libregrtest._parse_args([opt, '1000'])
                 self.assertEqual(ns.threshold, 1000)
                 self.checkError([opt], 'expected one argument')
                 self.checkError([opt, 'foo'], 'invalid int value')
@@ -232,13 +233,13 @@ def test_threshold(self):
     def test_nowindows(self):
         for opt in '-n', '--nowindows':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.nowindows)
 
     def test_forever(self):
         for opt in '-F', '--forever':
             with self.subTest(opt=opt):
-                ns = regrtest._parse_args([opt])
+                ns = libregrtest._parse_args([opt])
                 self.assertTrue(ns.forever)
 
 
@@ -246,26 +247,26 @@ def test_unrecognized_argument(self):
         self.checkError(['--xxx'], 'usage:')
 
     def test_long_option__partial(self):
-        ns = regrtest._parse_args(['--qui'])
+        ns = libregrtest._parse_args(['--qui'])
         self.assertTrue(ns.quiet)
         self.assertEqual(ns.verbose, 0)
 
     def test_two_options(self):
-        ns = regrtest._parse_args(['--quiet', '--exclude'])
+        ns = libregrtest._parse_args(['--quiet', '--exclude'])
         self.assertTrue(ns.quiet)
         self.assertEqual(ns.verbose, 0)
         self.assertTrue(ns.exclude)
 
     def test_option_with_empty_string_value(self):
-        ns = regrtest._parse_args(['--start', ''])
+        ns = libregrtest._parse_args(['--start', ''])
         self.assertEqual(ns.start, '')
 
     def test_arg(self):
-        ns = regrtest._parse_args(['foo'])
+        ns = libregrtest._parse_args(['foo'])
         self.assertEqual(ns.args, ['foo'])
 
     def test_option_and_arg(self):
-        ns = regrtest._parse_args(['--quiet', 'foo'])
+        ns = libregrtest._parse_args(['--quiet', 'foo'])
         self.assertTrue(ns.quiet)
         self.assertEqual(ns.verbose, 0)
         self.assertEqual(ns.args, ['foo'])