Do not exchange XMPP contacts when turned off by inviter

spec/models/user_spec.rb

@@ -139,6 +139,8 @@ RSpec.describe User, type: :model do
       let(:guest) { create :user, id: 2, cn: "isaacnewton", ou: "kosmos.org", email: "newt@example.com" }
 
       before do
+        # TODO remove when defaults are implemented
+        user.update! preferences: {"xmpp" => { "exchange_contacts_with_invitees" => true }}
         Invitation.create! user: user, invited_user_id: guest.id, used_at: DateTime.now
         allow_any_instance_of(User).to receive(:enable_service).and_return(true)
       end
@@ -147,6 +149,17 @@ RSpec.describe User, type: :model do
         expect(guest).to receive(:exchange_xmpp_contact_with_inviter)
         guest.send(:devise_after_confirmation)
       end
+
+      context "automatic contact exchange disabled" do
+        before do
+          user.update! preferences: {"xmpp" => { "exchange_contacts_with_invitees" => false }}
+        end
+
+        it "does not exchange XMPP contacts with the inviter" do
+          expect(guest).to_not receive(:exchange_xmpp_contact_with_inviter)
+          guest.send(:devise_after_confirmation)
+        end
+      end
     end
   end