id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
27132	Allowed testing MemcachedCache and PyLibMCCache during the same test run	Ed Morley	Ed Morley	"Currently jenkins only tests against MemcachedCache (ie python-memcached).

In order to make changes like those in #20892 easier to test, it would be useful if PyLibMCCache were tested on jenkins too.

This will likely involve:
* Adding a PyLibMCCache config to the jenkins configs (not sure whether these are in a public repo somewhere?)
* Refactoring tests/cache/tests.py, such that:
  - `MemcachedCacheTests` is split into a base class (that isn't a subclass of `TestCase`) plus `MemcachedCacheTests` and `PyLibMCCacheTests`  
  - the vast majority of tests are kept in the base class, with just the binding-specific tests in the subclasses
  - the subclasses have appropriate `@skipUnless()` and `@override_settings()`

For example:

{{{
MemcachedCache_params = {}
PyLibMCCache_params = {}
for _cache_params in settings.CACHES.values():
    backend = _cache_params['BACKEND']
    if backend == 'django.core.cache.backends.memcached.MemcachedCache':
        MemcachedCache = _cache_params
    elif backend == 'django.core.cache.backends.memcached.PyLibMCCache':
        PyLibMCCache_params = _cache_params

# ...

class BaseMemcachedTests(BaseCacheTests):

    def test_foo(self):
        # ...

@unittest.skipUnless(MemcachedCache_params, ""MemcachedCache backend not configured"")
@override_settings(CACHES=caches_setting_for_tests(
    base=MemcachedCache_params,
    exclude=memcached_excluded_caches,
))
class MemcachedCacheTests(BaseMemcachedTests, TestCase):

    def test_python_memcached__foo(self):
        # ...

@unittest.skipUnless(PyLibMCCache_params, ""PyLibMCCache backend not configured"")
@override_settings(CACHES=caches_setting_for_tests(
    base=PyLibMCCache_params,
    exclude=memcached_excluded_caches,
))
class PyLibMCCacheTests(BaseMemcachedTests, TestCase):

    def test_pylibmc_foo(self):
        # ...

}}}

However, there are both class level uses of `@override_settings()` and also per-test uses, and the per-test uses are for tests that will be in the base class `BaseMemcachedTests`.

What's the preferred way to inherit settings from the class-level `@override_settings()` usage of the subclasses (eg `PyLibMCCacheTests`), and to then modify them further on the tests run on the base class?"	Cleanup/optimization	closed	Core (Cache system)	dev	Normal	fixed		emorley@…	Accepted	1	0	0	0	0	0