I suspect that the test hangs because of the MSCRT assertion error popup: see issue #25305.

http://buildbot.python.org/all/builders/x86%20Windows7%203.x/builds/10279/steps/test/logs/stdio

[287/400/1] test_regrtest
Timeout (1:00:00)!
Thread 0x00000d48 (most recent call first):
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\subprocess.py", line 1279 in _readerthread
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\threading.py", line 871 in run
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\threading.py", line 923 in _bootstrap_inner
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\threading.py", line 891 in _bootstrap

Thread 0x000009b8 (most recent call first):
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\threading.py", line 1079 in _wait_for_tstate_lock
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\threading.py", line 1063 in join
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\subprocess.py", line 1308 in _communicate
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\subprocess.py", line 1068 in communicate
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\subprocess.py", line 698 in run
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\test_regrtest.py", line 395 in run_command
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\test_regrtest.py", line 417 in run_python
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\test_regrtest.py", line 524 in run_tests
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\test_regrtest.py", line 663 in test_huntrleaks_fd_leak
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\case.py", line 600 in run
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\case.py", line 648 in __call__
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\suite.py", line 122 in run
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\suite.py", line 84 in __call__
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\suite.py", line 122 in run
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\suite.py", line 84 in __call__
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\suite.py", line 122 in run
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\suite.py", line 84 in __call__
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\unittest\runner.py", line 176 in run
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\support\__init__.py", line 1775 in _run_suite
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\support\__init__.py", line 1809 in run_unittest
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\libregrtest\runtest.py", line 161 in test_runner
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\libregrtest\runtest.py", line 162 in runtest_inner
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\libregrtest\runtest.py", line 115 in runtest
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\libregrtest\main.py", line 293 in run_tests_sequential
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\libregrtest\main.py", line 352 in run_tests
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\libregrtest\main.py", line 388 in main
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\libregrtest\main.py", line 429 in main
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\lib\test\libregrtest\main.py", line 451 in main_in_temp_cwd
  File "D:\cygwin\home\db3l\buildarea\3.x.bolen-windows7\build\PCbuild\..\lib\test\regrtest.py", line 39 in <module>

command timed out: 3900 seconds without output