This reverts commit 3d2617983b.
The change was not quite right because the method six provides needs to
have `self` be passed in as well. See the docs here:
https://six.readthedocs.io/#unittest-assertions
Reverting for now and we can fix it in smaller chunks later.
* Convert to using ExitStack instead of nested.
nested is not available in Python3.
* Use ExitStack from contextlib2.
ExitStack has not been backported to the Python 2.7 standard library and
contextlib.nested is no longer available in Python 3.5. We need to be
able to use something in both 2 and 3 as we transition so we'll pull in
contextlib2 which has backports of the full python3 contextlib.
The `DEFAULT_SHOW_RESET_BUTTON` is not actually referenced anywhere
other than in these two places where it's read. As far as I can tell,
nothing sets this value so it's always going to fallback to false.
Since this mixin is imported during startup, removing this unblocks
testing on python3 where it can fail to start up if the settings haven't
fully loaded before you try to access them.
* INCR-214: python-modernize on common/lib/xmodule/xmodule/modulestore/tests
* Running isort on common/lib/xmodule/xmodule/modulestore/tests
* Resolving issues with mangled comments and fixing int/long test
All code in this PR should be removed after REVE-52 is merged and mobile
traffic from older app versions falls to < 5% of the mobile traffic
to the course_blocks api
The course_visiblity field can have one of three values:
1. private (default): This keeps the standard access rules.
2. public_outline: Allows unenrolled and anonymous users access to the outline.
3. public: Allows unenrolled and anonymous users access to both outline and
course content.
When an unenrolled user accesses course content, instead of student_view(),
public_view() is used. A default implementation is provided for XBlocks
which do not implement this view. The public_view() must not have any
functionality which assumes the presence of a valid User and should show
a readonly only interface for the XBlock content.
