Filter out installed apps from recommendations list (bug 1109126)

The recommendation engine should do this but may not in some cases.

Author: Rob Hudson

mkt/recommendations/tests/test_views.py

@@ -152,3 +152,12 @@ def test_no_filter_if_no_dev(self):
         eq_(len(objects), 2)
         self.assertSetEqual([a['id'] for a in objects],
                             [a.pk for a in self.apps])
+
+    def test_no_installed_apps(self):
+        self.profile.installed_set.create(addon=self.apps[0])
+
+        res = self.client.get(self.url)
+        eq_(res.status_code, 200)
+        objects = res.json['objects']
+        eq_(len(objects), 1)
+        self.assertSetEqual([a['id'] for a in objects], [self.apps[1].pk])

mkt/recommendations/views.py

@@ -57,6 +57,11 @@ def list(self, request, *args, **kwargs):
                 # Fall back to a popularity search.
                 return self._popular()
 
+            # Get list of installed apps and remove from app_ids.
+            installed = list(
+                request.user.installed_set.values_list('addon_id', flat=True))
+            app_ids = filter(lambda a: a not in installed, app_ids)
+
             device = get_device_id(request)
             filters = {'device': device} if device else None