bpo-27200: fix pathlib, ssl, turtle and weakref doctests

[marco-buttu]

This PR is the last but one in the series bpo-27200. The first one was #240, the second one #401, and the third #604. To run the doctests (from the Doc directory):

$ sphinx-build -b doctest . build/doctest \
library/pathlib.rst \
library/ssl.rst \
library/turtle.rst \
library/weakref.rst

[mention-bot]

@marco-buttu, thanks for your PR! By analyzing the history of the files in this pull request, we identified @eliben, @birkenfeld, @vsajip, @tiran and @loewis to be potential reviewers.

[marco-buttu]

The setcontext(Context()) in testsetup does not guarantee that the tests outside this file get a fresh context. We need to clean the context at the end of the tests.

[berkerpeksag]

Please leave decimal.rst changes out of this PR and open a separate PR and then ping Stefan Krah.

[berkerpeksag]

I think we also need to following change to ssl examples:

diff --git a/Doc/library/ssl.rst b/Doc/library/ssl.rst
index 01dbecd..02a0c79 100644
--- a/Doc/library/ssl.rst
+++ b/Doc/library/ssl.rst
@@ -2262,7 +2262,7 @@ SSL versions 2 and 3 are considered insecure and are therefore dangerous to
 use.  If you want maximum compatibility between clients and servers, it is
 recommended to use :const:`PROTOCOL_TLS_CLIENT` or
 :const:`PROTOCOL_TLS_SERVER` as the protocol version. SSLv2 and SSLv3 are
-disabled by default.
+disabled by default. ::
 
    >>> client_context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
    >>> client_context.options |= ssl.OP_NO_TLSv1

And there are the other failures:

**********************************************************************
File "library/ssl.rst", line 421, in newcontext
Failed example:
    timestamp
Expected:
    1515144883
Got:
    1515134083.0
**********************************************************************
File "library/ssl.rst", line 424, in newcontext
Failed example:
    print(datetime.utcfromtimestamp(timestamp))
Expected:
    2018-01-05 09:34:43
Got:
    2018-01-05 06:34:43

[berkerpeksag]

Please leave decimal.rst changes out of this PR and open a separate PR and then ping Stefan Krah.

[berkerpeksag]

You have already modified this file in #604.

[berkerpeksag]

Please revert this change. The current version looks correct to me and the tests passed when I revert it to use ::.

[marco-buttu]

Thank you very much for your time @berkerpeksag! I made all changes you requested me. Just one question: you got a float from ssl.cert_time_to_seconds(). Is it not a bug in the code? Is it supposed to return both floats and ints?

[berkerpeksag]

I don't know, it's probably worth doing some VCS archaeology :) I built and ran tests in Python 3.4 with an ancient OpenSSL so this might be the culprit.

[berkerpeksag]

I know I suggested this style in my earlier comment, but could you move :: to a new line so we don't lose git blame information? This also applies to the changes in Doc/library/pathlib.rst.

[marco-buttu]

Ok, done :-) Thanks againt @berkerpeksag

[berkerpeksag]

Thanks!