Add endpoint to show artwork

app/controllers/api/using_nothing/artworks_controller.rb

@@ -5,6 +5,11 @@ def index
         artworks = Artwork.all
         render json: artworks
       end
+
+      def show
+        artwork = Artwork.find(params[:id])
+        render json: artwork
+      end
     end
   end
 end

spec/requests/using_nothing/show_artwork_spec.rb

@@ -0,0 +1,20 @@
+require "rails_helper"
+
+describe "/api/using_nothing/artworks/:id" do
+  let!(:artwork) { FactoryBot.create(:artwork) }
+
+  context "with invalid id" do
+    it "returns a 404" do
+      get "/api/using_nothing/artworks/invalid"
+      expect(response.status).to eq 404
+    end
+  end
+
+  context "with valid id" do
+    it "returns that artwork" do
+      get "/api/using_nothing/artworks/#{artwork.id}"
+      expect(response.status).to eq 200
+      expect(response.parsed_body).to eq artwork.as_json
+    end
+  end
+end