AO3-7386 Display 404 when loading drafts with an invalid user

app/controllers/works_controller.rb

@@ -152,11 +152,7 @@ def collected
   end
 
   def drafts
-    unless params[:user_id] && (@user = User.find_by(login: params[:user_id]))
-      flash[:error] = ts('Whose drafts did you want to look at?')
-      redirect_to users_path
-      return
-    end
+    @user = User.find_by!(login: params[:user_id])
 
     unless current_user == @user || logged_in_as_admin?
       flash[:error] = ts('You can only see your own drafts, sorry!')

spec/controllers/works/drafts_spec.rb

@@ -19,13 +19,6 @@
   end
 
   describe "drafts" do
-    context "when no user_id is specified" do
-      it "redirects to the user controller and display an appropriate error message" do
-        get :drafts
-        it_redirects_to_with_error(users_path, "Whose drafts did you want to look at?")
-      end
-    end
-
     context "when logged out" do
       before { fake_logout }
 
@@ -76,6 +69,14 @@
                                    "You can only see your own drafts, sorry!")
       end
     end
+
+    context "when the requested user does not exist" do
+      it "raises a RecordNotFound error" do
+        expect do
+          get :drafts, params: { user_id: "invalid-user" }
+        end.to raise_error(ActiveRecord::RecordNotFound)
+      end
+    end
   end
 
   describe "post_draft" do