diff --git a/spec/controllers/similar_topics_controller_spec.rb b/spec/controllers/similar_topics_controller_spec.rb
deleted file mode 100644
index f7dad39562b..00000000000
--- a/spec/controllers/similar_topics_controller_spec.rb
+++ /dev/null
@@ -1,61 +0,0 @@
-require 'rails_helper'
-
-describe SimilarTopicsController do
-  context 'similar_to' do
-
-    let(:title) { 'this title is long enough to search for' }
-    let(:raw) { 'this body is long enough to search for' }
-
-    it "requires a title" do
-      expect do
-        get :index, params: { raw: raw }, format: :json
-      end.to raise_error(ActionController::ParameterMissing)
-    end
-
-    it "returns no results if the title length is below the minimum" do
-      Topic.expects(:similar_to).never
-      SiteSetting.min_title_similar_length = 100
-      get :index, params: { title: title, raw: raw }, format: :json
-      json = ::JSON.parse(response.body)
-      expect(json["similar_topics"].size).to eq(0)
-    end
-
-    describe "minimum_topics_similar" do
-
-      before do
-        SiteSetting.minimum_topics_similar = 30
-      end
-
-      after do
-        get :index, params: { title: title, raw: raw }, format: :json
-      end
-
-      describe "With enough topics" do
-        before do
-          Topic.stubs(:count).returns(50)
-        end
-
-        it "deletes to Topic.similar_to if there are more topics than `minimum_topics_similar`" do
-          Topic.expects(:similar_to).with(title, raw, nil).returns([Fabricate(:topic)])
-        end
-
-        describe "with a logged in user" do
-          let(:user) { log_in }
-
-          it "passes a user through if logged in" do
-            Topic.expects(:similar_to).with(title, raw, user).returns([Fabricate(:topic)])
-          end
-        end
-
-      end
-
-      it "does not call Topic.similar_to if there are fewer topics than `minimum_topics_similar`" do
-        Topic.stubs(:count).returns(10)
-        Topic.expects(:similar_to).never
-      end
-
-    end
-
-  end
-
-end
diff --git a/spec/requests/similar_topics_controller_spec.rb b/spec/requests/similar_topics_controller_spec.rb
new file mode 100644
index 00000000000..d6692bab3fb
--- /dev/null
+++ b/spec/requests/similar_topics_controller_spec.rb
@@ -0,0 +1,91 @@
+require 'rails_helper'
+
+describe SimilarTopicsController do
+  context 'similar_to' do
+    let(:title) { 'this title is long enough to search for' }
+    let(:raw) { 'this body is long enough to search for' }
+
+    let(:topic) { Fabricate(:topic, title: title) }
+    let(:post) { Fabricate(:post, topic: topic, raw: raw, post_number: 1) }
+
+    let(:private_post) { Fabricate(:post, raw: raw, topic: private_topic, post_number: 1) }
+    let(:private_topic) do
+      Fabricate(:topic, title: "#{title} 02", category: Fabricate(:private_category, group: Group[:staff]))
+    end
+
+    def reindex_posts
+      SearchIndexer.enable
+      Jobs::ReindexSearch.new.rebuild_problem_posts
+    end
+
+    it "requires a title param" do
+      get "/topics/similar_to.json", params: { raw: raw }
+      expect(response.status).to eq(400)
+    end
+
+    it "returns no results if the title length is below the minimum" do
+      SiteSetting.minimum_topics_similar = 0
+      SiteSetting.min_title_similar_length = 100
+      post
+      reindex_posts
+
+      get "/topics/similar_to.json", params: { title: title, raw: raw }
+      expect(response).to be_success
+      json = ::JSON.parse(response.body)
+      expect(json["similar_topics"].size).to eq(0)
+    end
+
+    describe "minimum_topics_similar" do
+      before do
+        SiteSetting.minimum_topics_similar = 30
+      end
+
+      describe "With enough topics" do
+        it "deletes to Topic.similar_to if there are more topics than `minimum_topics_similar`" do
+          Topic.stubs(:count).returns(50)
+          post
+          reindex_posts
+
+          get "/topics/similar_to.json", params: { title: title, raw: raw }
+
+          expect(response).to be_success
+          similar_topics = ::JSON.parse(response.body)["similar_topics"]
+          expect(similar_topics.size).to eq(1)
+          expect(similar_topics.first["topic_id"]).to eq(topic.id)
+        end
+
+        describe "with a logged in user" do
+          before do
+            private_post; post
+            reindex_posts
+            Topic.stubs(:count).returns(50)
+            sign_in(Fabricate(:moderator))
+            Group.refresh_automatic_groups!
+          end
+
+          it "passes a user through if logged in" do
+            get "/topics/similar_to.json", params: { title: title, raw: raw }
+
+            expect(response).to be_success
+            similar_topics = ::JSON.parse(response.body)["similar_topics"].map { |topic| topic["topic_id"] }
+            expect(similar_topics.size).to eq(2)
+            expect(similar_topics).to include(topic.id)
+            expect(similar_topics).to include(private_topic.id)
+          end
+        end
+      end
+
+      it "does not call Topic.similar_to if there are fewer topics than `minimum_topics_similar`" do
+        Topic.stubs(:count).returns(10)
+        post
+        reindex_posts
+
+        get "/topics/similar_to.json", params: { title: title, raw: raw }
+
+        expect(response).to be_success
+        json = ::JSON.parse(response.body)
+        expect(json["similar_topics"].size).to eq(0)
+      end
+    end
+  end
+end