Implementation of floordiv is incorrect for polynomials over finite fields

[JohnCremona]

As reported on sage-devel, the following is incorrect:

sage: F = GF(47)
sage: x = polygen(F)
sage: u = F(1)
sage: x//u
0

since x//u should give the quotient after dividing x by u.

This is fixed by #2034, so this ticket just adds a doctest.

Depends on #2034

Component: algebra

Keywords: polynomial division

Author: Jeroen Demeyer

Branch/Commit: bca94fc

Reviewer: Vincent Delecroix

Issue created by migration from https://trac.sagemath.org/ticket/16781

[jdemeyer]

Dependencies: #2034

[jdemeyer]

Branch: u/jdemeyer/ticket/16781

[jdemeyer]

New commits:

5e8a5e3	Implement `__floordiv__` in the coercion model
227e8bb	Add doctest for floor division

[jdemeyer]

Author: Jeroen Demeyer

[jdemeyer]

Commit: 227e8bb

[videlec]

comment:6

Could you be more careful with

sage: 1 // x
0

and actually test the parent of the "0" you got?

[videlec]

Reviewer: Vincent Delecroix

[sagetrac-git]

Changed commit from 227e8bb to bca94fc

[sagetrac-git]

Branch pushed to git repo; I updated commit sha1. New commits:

bca94fc

Doctest also the parent of floor division

[vbraun]

Changed branch from u/jdemeyer/ticket/16781 to bca94fc