hkeys() does not return all keys

[aschriner]

django-hstore/django_hstore/query.py

Lines 155 to 162 in 355388c

	@select_query
	def hkeys(self, query, attr):
	"""
	Enumerates the keys in the specified hstore.
	"""
	query.add_extra({'_': 'akeys("%s")' % attr}, None, None, None, None, None)
	result = query.get_compiler(self.db).execute_sql(SINGLE)
	return (result[0] if result else [])

I've verified in my own code that this is not returning all keys.

http://stackoverflow.com/questions/12015942/most-efficient-way-to-retrieve-a-unique-list-of-keys-from-all-rows-of-an-hstore

The hkeys() method probably needs a DISTINCT clause. Will follow up with a PR.

Update:

• I'm trying to use hkeys on a queryset, which isn't mentioned in the docs. So I think I'm looking at adding functionality here rather than fixing a bug.
• I'm trying to get tests running locally and I'm seeing some errors with dependencies. I've pip installed requirements.txt but still seeing stuff like django.core.exceptions.ImproperlyConfigured: GEOS is required and has not been detected. Are you sure it is installed? See also https://docs.djangoproject.com/en/1.8/ref/contrib/gis/install/geolibs/ Can you provide any info on how to get tests running locally, what needs to be installed, etc?

[nemesifier]

You can run tests for psycopg only and avoid having to install the GIS libraries:

./runtests.py --settings=settings_psycopg