Refactor IssuableFinder to extract model-specific logic

By extracting a new `filter_items` method, we can override that in the
IssuesFinder and MergeRequestsFinder separately, so we don't need checks that
the model is the correct one, because we can just use the class we're in to know
that.

We can do the same for the VALID_PARAMS constant, by making it a class method.

1 files changed, 4 insertions, 0 deletions

diff --git a/spec/controllers/concerns/issuable_collections_spec.rb b/spec/controllers/concerns/issuable_collections_spec.rb
index d7825364ed5..c1f42bbb9d7 100644
--- a/spec/controllers/concerns/issuable_collections_spec.rb
+++ b/spec/controllers/concerns/issuable_collections_spec.rb
@@ -8,6 +8,10 @@ describe IssuableCollections do
       def self.helper_method(name); end
 
       include IssuableCollections
+
+      def finder_type
+        IssuesFinder
+      end
     end
 
     controller = klass.new