Emulate reconfigure on Python 3.6 and lower

[jayvdb]

Im not sure how much effort is required, but if the streams have a .reconfigure then the context manager constructor doesnt need to have lots of arguments for possible configurations of the stream.

[jayvdb]

Maybe upstream this to six or future, if not already present there.

[bskinn]

<nod>, I hadn't realized how much less important the encodings were for mocks like this, as compared to the real streams.

Seems like classifying this for now as YAGNI is the best approach -- as you say, only worrying about implementation if a future user needs it.

[jayvdb]

We may run into problem with pytest, due to pytest-dev/pytest#4843 and pytest-dev/pytest#4389

[jayvdb]

Current code at https://github.com/python/cpython/blob/c4cacc8/Lib/_pyio.py#L2118 . It looks like most of it should be fairly easy to backport, except that write_through may not be possible / or be tricky on the C version of the objects. But the note on the __init__ indicates the .py version already differs from the C version in that regards.

I cant find an existing backport in future, and it looks way beyond scope for six.
https://github.com/kislyuk/eight/blob/fdd59842a92dc17bed5a372d64fc9e95f7285a8b/eight/__init__.py#L86 is one backport.

https://github.com/ipython/ipykernel/blob/master/ipykernel/iostream.py is a rewrite, which they apparently want to keep in sync with the wrapper class ipython/ipykernel#178 .

[jayvdb]

Created PythonCharmers/python-future#498 for adding backport there

[bskinn]

With 3.6 now firmly EOL, not going to bother with this.