app/controllers/signup_controller.rb

@@ -104,7 +104,5 @@ class SignupController < ApplicationController
       password: @user.password,
       invitation: @invitation
     )
-
-    @invitation.update! invited_user_id: @user.id, used_at: DateTime.now
   end
 end

app/services/create_account.rb

@@ -8,8 +8,9 @@ class CreateAccount < ApplicationService
   end
 
   def call
-    create_user_in_database
+    user = create_user_in_database
     add_ldap_document
+    update_invitation(user.id) if @invitation.present?
   end
 
   private
@@ -24,6 +25,10 @@ class CreateAccount < ApplicationService
     )
   end
 
+  def update_invitation(user_id)
+    @invitation.update! invited_user_id: user_id, used_at: DateTime.now
+  end
+
   def add_ldap_document
     dn = "cn=#{@username},ou=kosmos.org,cn=users,dc=kosmos,dc=org"
     attr = {

spec/services/create_account_spec.rb

@@ -23,6 +23,28 @@ RSpec.describe CreateAccount, type: :model do
     end
   end
 
+  describe "#update_invitation" do
+    let(:invitation) { create :invitation }
+    let(:service) { CreateAccount.new(
+      username: 'isaacnewton',
+      email: 'isaacnewton@example.com',
+      password: 'bright-ideas-in-autumn',
+      invitation: invitation
+    )}
+
+    before(:each) do
+      service.send(:update_invitation, 23)
+    end
+
+    it "marks the invitation as used" do
+      expect(invitation.used_at).not_to be_nil
+    end
+
+    it "saves the invited user's ID" do
+      expect(invitation.invited_user_id).to eq(23)
+    end
+  end
+
   describe "#add_ldap_document" do
     let(:service) { CreateAccount.new(
       username: 'halfinney',