py3: miscellaneous test fixes in sage.structure

[embray]

Along with a little bit of PEP-8 cleanup as well.

I don't believe the substance of any of these tests are changed (there was one case where an old-style class was updated to be a new-style class, but all that matters for the test is that it be an arbitrary object that can be weak-referenced).

[git]

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

​7be6459

py3: miscellaneous minor test fixes for Python 3

[sbrandhorst]

Dear Erik, I can review this ticket. But it is my first py3 review. What do I need to do? Best, Simon

[vklein]

@sbrandhorst. If your question is how to build/run sage with python3 see ​Python3-compatible code

[sbrandhorst]

ah thank you. I will build with python3 and continue the review tomorrow.

[embray]

It looks like there were a few test failures. They're trivial but should be fixed.

[embray]

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

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​04af88a	py3: miscellaneous minor test fixes for Python 3
​4b41a9f	These should be spelled '<type ...>' for Python 2 compatibility; the Python 3 spelling is handled automatically by the test framework

[embray]

Rebased and fixed the failing tests.

[vklein]

Almost a positive review, the very last modification i checked failed in py3 :

File "src/sage/structure/unique_representation.py", line 1244, in sage.structure.unique_representation.UniqueRepresentation
Failed example:
    isinstance(GF(7), GF)  # py3
Expected:
    Traceback (most recent call last):
    ...
    TypeError: isinstance() arg 2 must be a class, type, or tuple of
    classes and types
Got:
    <BLANKLINE>
    Traceback (most recent call last):
      File "/home/vklein/odk/sage/local/lib/python3.6/site-packages/sage/doctest/forker.py", line 650, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/home/vklein/odk/sage/local/lib/python3.6/site-packages/sage/doctest/forker.py", line 1061, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.structure.unique_representation.UniqueRepresentation[7]>", line 1, in <module>
        isinstance(GF(Integer(7)), GF)  # py3
    TypeError: isinstance() arg 2 must be a type or tuple of types

Note that your #py2 and #py3 cases expected the same results right now :

+        sage: isinstance(GF(7), GF)  # py2
         Traceback (most recent call last):
         ...
         TypeError: isinstance() arg 2 must be a class, type, or tuple of classes and types
+        sage: isinstance(GF(7), GF)  # py3
+        Traceback (most recent call last):
+        ...
+        TypeError: isinstance() arg 2 must be a class, type, or tuple of
+        classes and types

[embray]

Oh, that's silly. Thanks for checking!

[chapoton]

I made the correction

---

New commits:

​17afe48	Merge branch 'u/embray/python3/sage-structure/misc-test-fixes' in 8.4.b5
​986be9a	trac 25694 fixing py3 doctest

[embray]

Thank you!

[vklein]

Ok then.