Issue #23799: Added test.support.start_threads() for running and cleaning up

multiple threads.

1 files changed, 38 insertions, 1 deletions

diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index 1919082..82321af 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -6,6 +6,7 @@ if __name__ != 'test.support':
 import collections.abc
 import contextlib
 import errno
+import faulthandler
 import fnmatch
 import functools
 import gc
@@ -96,7 +97,7 @@ __all__ = [
     # logging
     "TestHandler",
     # threads
-    "threading_setup", "threading_cleanup",
+    "threading_setup", "threading_cleanup", "reap_threads", "start_threads",
     # miscellaneous
     "check_warnings", "EnvironmentVarGuard", "run_with_locale", "swap_item",
     "swap_attr", "Matcher", "set_memlimit", "SuppressCrashReport", "sortdict",
@@ -1942,6 +1943,42 @@ def reap_children():
                 break
 
 @contextlib.contextmanager
+def start_threads(threads, unlock=None):
+    threads = list(threads)
+    started = []
+    try:
+        try:
+            for t in threads:
+                t.start()
+                started.append(t)
+        except:
+            if verbose:
+                print("Can't start %d threads, only %d threads started" %
+                      (len(threads), len(started)))
+            raise
+        yield
+    finally:
+        try:
+            if unlock:
+                unlock()
+            endtime = starttime = time.time()
+            for timeout in range(1, 16):
+                endtime += 60
+                for t in started:
+                    t.join(max(endtime - time.time(), 0.01))
+                started = [t for t in started if t.isAlive()]
+                if not started:
+                    break
+                if verbose:
+                    print('Unable to join %d threads during a period of '
+                          '%d minutes' % (len(started), timeout))
+        finally:
+            started = [t for t in started if t.isAlive()]
+            if started:
+                faulthandler.dump_traceback(sys.stdout)
+                raise AssertionError('Unable to join %d threads' % len(started))
+
+@contextlib.contextmanager
 def swap_attr(obj, attr, new_val):
     """Temporary swap out an attribute with a new object.