use limit & offset for pagination of group members

app/controllers/groups_controller.rb

@@ -18,8 +18,11 @@ class GroupsController < ApplicationController
 
   def members
     group = find_group(:group_id)
-    members = group.users.order('username_lower asc')
-    members = members.limit(200) if group.automatic
+
+    limit = (params[:limit] || 200).to_i
+    offset = (params[:offset] || 0).to_i
+    members = group.users.order('username_lower asc').limit(limit).offset(offset)
+
     render_serialized(members.to_a, GroupUserSerializer)
   end
 

spec/controllers/groups_controller_spec.rb

@@ -67,5 +67,19 @@ describe GroupsController do
       xhr :get, :posts, group_id: group.name
       response.should be_success
     end
+
+    it "ensures that membership can be paginated" do
+      5.times { group.add(Fabricate(:user)) }
+      xhr :get, :members, group_id: group.name, limit: 3
+      response.should be_success
+      members = JSON.parse(response.body)
+      members.count.should eq(3)
+
+      xhr :get, :members, group_id: group.name, limit: 250, offset: 250
+      xhr :get, :members, group_id: group.name, limit: 3, offset: 3
+      response.should be_success
+      members = JSON.parse(response.body)
+      members.count.should eq(2)
+    end
   end
 end