Deduplicate filter results

when both a card and that card's comments match the search term, we
don't want to show it multiple times.

ref: https://app.fizzy.do/5986089/cards/3030

app/models/filter.rb

@@ -36,7 +36,7 @@ class Filter < ApplicationRecord
         result.mentioning(term, user: creator)
       end
 
-      result
+      result.distinct
     end
   end
 

test/models/filter/search_test.rb

@@ -0,0 +1,19 @@
+require "test_helper"
+
+class Filter::SearchTest < ActiveSupport::TestCase
+  include SearchTestHelper
+
+  test "deduplicate multiple results" do
+    user = users(:david)
+
+    board = boards(:writebook)
+    card = board.cards.create!(title: "Duplicate results test", description: "Have you had any haggis today?", creator: user)
+    card.published!
+    card.comments.create(body: "I hate haggis.", creator: user)
+    card.comments.create(body: "I love haggis.", creator: user)
+
+    filter = user.filters.new(terms: [ "haggis" ], indexed_by: "all", sorted_by: "latest")
+
+    assert_equal [ card ], filter.cards.to_a
+  end
+end