Markup fixes to use :exc:, :option: in a few places.
  (Glitch: unittest.main's -c ends up a link to the Python
  interpreter's -c option.  Should we skip using :option: for that
  switch, or disable the auto-linking somehow?)

and remove a duplicate of its specification.

Issue 8202: when using the -m command line switch, sys.argv[0] is now '-m' instead of '-c' while searching for the module to be executed

Issue 7490: make IGNORE_EXCEPTION_DETAIL also ignore details of the module containing the exception under test (original patch by Lennart Regebro)

 * Use try/except ImportError or test_support.import_module() to import thread
   and threading modules
 * Add @unittest.skipUnless(threading, ...) to testcases using threads

Use test_support.import_module() instead of import to raise a SkipTest
exception if the import fail. Import trace fails if the threading module is
missing.

See also part 3: test_doctest: import trace module in test_coverage().

Rewrite r80556: the thread test have to be executed just after the test on
libc_open() and so the test cannot be splitted in two functions (without
duplicating code, and I don't want to duplicate code).

 * Skip testcases using threads if threading module is missing
 * Use "http://" instead of URL in ServerProxyTestCase if threading is missing
   because URL is not set in this case

TestFifo can be executed without the threading module

 * Skip TestPendingCalls if threading module is missing
 * Test if threading module is present or not, instead of test the presence of
   _testcapi._test_thread_state

Move @test_support.reap_thread decorator from test_main() to test_threaded_hashing().

before the certificate footer.  Patch by Kyle VanderBeek.

 * Split Test.test_open() in 2 functions: test_open() and test_thread_open()
 * Skip test_open() and test_thread_open() if we are unable to find the C
   library
 * Skip test_thread_open() if thread support is disabled
 * Use unittest.skipUnless(os.name == "nt", ...) on test_GetLastError()

import threading after _multiprocessing to raise a more revelant error message:
"No module named _multiprocessing". _multiprocessing is not compiled without
thread support.

Import trace module fail if the threading module is missing. test_coverage() is
only used if test_doctest.py is used with the -c option. This commit allows to
execute the test suite without thread support.

Move "import trace" in test_coverage() and use
test_support.import_module('trace').

Sridhar Ratnakumar.

Remove uses of test_support.TestFailed.

+ enable test that was never run (!)
+ make tests faster by lowering polling timeout

Refactors format_string.  Includes tests for the two problems noted in
the issue, but as far as I can see there are no other tests that confirm
that format_string conforms to normal % formatting rules.

caused by the "socket not connected" condition.