Add rspec tests for searching by a filetype.

spec/components/search_spec.rb

@@ -703,6 +703,24 @@ describe Search do
       expect(Search.execute('green tags:eggs').posts.map(&:id)).to eq([post2.id])
       expect(Search.execute('green tags:plants').posts.size).to eq(0)
     end
+
+    it "can find posts which contains filetypes" do
+      # Must be posts with real images
+      post1 = Fabricate(:post,
+                        raw: "https://www.discourse.org/a/img/favicon.png")
+      post2 = Fabricate(:post,
+                         raw: "Discourse logo\n"\
+                              "https://www.discourse.org/a/img/favicon.png\n"\
+                              "https://www.discourse.org/a/img/trust-1x.jpg")
+      Fabricate(:post)
+
+      TopicLink.extract_from(post1)
+      TopicLink.extract_from(post2)
+
+      expect(Search.execute('filetype:jpg').posts.map(&:id)).to eq([post2.id])
+      expect(Search.execute('filetype:png').posts.map(&:id)).to contain_exactly(post1.id, post2.id)
+      expect(Search.execute('logo filetype:jpg').posts.map(&:id)).to eq([post2.id])
+    end
   end
 
   it 'can parse complex strings using ts_query helper' do