add e2e spec

spec/system/users/change_email_spec.rb

@@ -29,3 +29,36 @@ describe 'Changing an email' do
     expect(user.reload.email).to eq(new_email)
   end
 end
+
+describe 'Merging account' do
+  let(:old_user) { create(:user) }
+  let(:new_user) { create(:user) }
+
+  before do
+    login_as old_user, scope: :user
+  end
+
+  scenario 'is easy' do
+    visit '/profil'
+
+    fill_in :user_email, with: new_user.email
+
+    perform_enqueued_jobs do
+      click_button 'Changer mon adresse'
+    end
+
+    expect(page).to have_content(I18n.t('devise.registrations.update_needs_confirmation'))
+    expect(page).to have_content(old_user.email)
+    expect(page).to have_content(new_user.email)
+
+    login_as new_user, scope: :user
+    visit '/profil'
+
+    expect(page).to have_content("Acceptez-vous d’absorber le compte de #{old_user.email}")
+    click_on 'Accepter la fusion'
+
+    expect(page).not_to have_content(old_user.email)
+    expect(page).to have_content(new_user.email)
+    expect { old_user.reload }.to raise_error(ActiveRecord::RecordNotFound)
+  end
+end