py3: Automatically alias OSError subclasses in exception doctests

[embray]

There are at least a handful of doctests that expect OSError to be raised. However, Python 3 added many OSError subclasses that are raised in many common cases instead (e.g. FileNotFoundError).

This patches doctest results to paper over this difference in doctests written against Python 2.

CC: @slel @vinklein

Component: python3

Author: Erik Bray

Branch/Commit: 4fff9a0

Reviewer: Frédéric Chapoton, Vincent Klein

Issue created by migration from https://trac.sagemath.org/ticket/25676

[fchapoton]

comment:3

pyflakes plugin is not happy..

[embray]

comment:4

Replying to @fchapoton:

pyflakes plugin is not happy..

Not due to anything related to these changes. If someone will otherwise give a conditional positive review to this ticket I'll make sure the pyflakes warnings get taken care of as a rider to this before it's merged.

[vinklein]

comment:6

Edit remove old comment as it matters only with twisted ways of building error messages.

[vinklein]

comment:7

Why two line break ?

                                    exc_msg = exc_msg.replace(subcls, 'OSError',

                                                              1)

[embray]

comment:8

Huh?

[vinklein]

comment:9

i mean why writing :

exc_msg = exc_msg.replace(subcls, 'OSError',

                          1)

rather than

exc_msg = exc_msg.replace(subcls, 'OSError',
                          1)

I am not saying it's an important issue (it's not). I just wonder why.

[embray]

comment:10

I don't know. My editor is configured to enforce a 79 character line and knows Python syntax (most of the time) so it will bump things onto the next line when it can.

[slel]

comment:11

Name the subclass "sc" instead of "subcls"
in the for loop to get a shorter line?

[embray]

comment:12

It's....really okay.

[fchapoton]

comment:13

let it be

[fchapoton]

Reviewer: Frédéric Chapoton, Vincent Klein

[embray]

comment:14

I believe this issue can reasonably be addressed for Sage 8.4.

[vbraun]

Changed branch from u/embray/python3/doctest/oserror-subclasses to 4fff9a0