tests.

testcase failure in test_ssl.

issue10403 - Let's not use members anymore. Use 'attribute' where it denotes attribute and 'methods' where it denotes methods. Context should clarify usage.

fresh process with only one thread and to not change signal handling of the
parent process.

On FreeBSD, the SIGALRM signal is sometimes received by the reader thread.

test_tk or test_ttk_guionly under a username that is not currently logged
in to the console windowserver (as may be the case under buildbot or ssh).

shutdown, if globals()['__file__'] is None.

shutdown, if globals()['__file__'] is None.

instead of text mode using the locale encoding, to avoid encoding issues.

instead of text mode using the locale encoding, to support other encodings than
UTF-8 (scripts using the coding cookie).

of the text mode (using the locale encoding) to avoid encoding issues.

This requires some trickery to properly save the exception state if the
generator creates its own exception state.

This prevents generator exception state from leaking into the caller.

Closes #12475.

freed by the garbage collector while the Heap lock is held.

the garbage collector while the Heap lock is held.

Move also the "ready" trigger after the installation of the signal handler and
the call to siginterrupt().

Use a timeout of 5 seconds instead of 3. Two seconds are supposed to be enough,
but some of our buildbots are really slow (especially the FreeBSD 6 VM).

Backport commits 968b9ff9a059 and aff0a7b0cb12 from the default branch to 3.2
branch. Extract of the changelog messages:

"The previous tests used time.sleep() to synchronize two processes. If the host
was too slow, the test could fail.

The new tests only use one process, but they use a subprocess to:

- have only one thread
- have a timeout on the blocking read (select cannot be used in the test,
select always fail with EINTR, the kernel doesn't restart it)
- not touch signal handling of the parent process"

and

"Add a basic synchronization code between the child and the parent processes:
the child writes "ready" to stdout."

I replaced .communicate(timeout=3.0) by an explicit waiting loop using
Popen.poll().

with known OS bugs

Share the list of platforms with known OS bugs with other tests. Patch written
by Charles-François Natali.