specs: migrate from features to system specs

System specs have been available since Rails 5.1, and are better
integrated with the Rails framework.

- Rename `spec/features` to `spec/system`
- Rename `feature do` to `describe do`
- Configure Capybara for system specs

Steps mostly taken from https://medium.com/table-xi/a-quick-guide-to-rails-system-tests-in-rspec-b6e9e8a8b5f6

spec/system/users/sign_up_spec.rb

@@ -0,0 +1,147 @@
+describe 'Signing up:' do
+  let(:user_email) { generate :user_email }
+  let(:user_password) { 'my-s3cure-p4ssword' }
+  let(:procedure) { create :simple_procedure, :with_service }
+
+  scenario 'a new user can sign-up from scratch' do
+    visit new_user_registration_path
+
+    sign_up_with user_email, user_password
+    expect(page).to have_content "nous avons besoin de vérifier votre adresse #{user_email}"
+
+    click_confirmation_link_for user_email
+    expect(page).to have_content('Votre compte a bien été confirmé.')
+    expect(page).to have_current_path dossiers_path
+  end
+
+  context 'when the user makes a typo in their email address' do
+    let(:procedure) { create :simple_procedure, :with_service }
+
+    before do
+      visit commencer_path(path: procedure.path)
+      click_on "Créer un compte #{APPLICATION_NAME}"
+      expect(page).to have_selector('.suspect-email', visible: false)
+      fill_in 'Email', with: 'bidou@yahoo.rf'
+      fill_in 'Mot de passe', with: '12345'
+    end
+
+    scenario 'they can accept the suggestion', js: true do
+      expect(page).to have_selector('.suspect-email', visible: true)
+      click_on 'Oui'
+      expect(page).to have_field("Email", :with => 'bidou@yahoo.fr')
+      expect(page).to have_selector('.suspect-email', visible: false)
+    end
+
+    scenario 'they can discard the suggestion', js: true do
+      expect(page).to have_selector('.suspect-email', visible: true)
+      click_on 'Non'
+      expect(page).to have_field("Email", :with => 'bidou@yahoo.rf')
+      expect(page).to have_selector('.suspect-email', visible: false)
+    end
+
+    scenario 'they can fix the typo themselves', js: true do
+      expect(page).to have_selector('.suspect-email', visible: true)
+      fill_in 'Email', with: 'bidou@yahoo.fr'
+      blur
+      expect(page).to have_selector('.suspect-email', visible: false)
+    end
+  end
+
+  scenario 'a new user can’t sign-up with too short password when visiting a procedure' do
+    visit commencer_path(path: procedure.path)
+    click_on "Créer un compte #{APPLICATION_NAME}"
+
+    expect(page).to have_current_path new_user_registration_path
+    sign_up_with user_email, '1234567'
+    expect(page).to have_current_path user_registration_path
+    expect(page).to have_content 'Le mot de passe est trop court'
+
+    # Then with a good password
+    sign_up_with user_email, user_password
+    expect(page).to have_current_path new_user_confirmation_path user: { email: user_email }
+    expect(page).to have_content "nous avons besoin de vérifier votre adresse #{user_email}"
+  end
+
+  context 'when visiting a procedure' do
+    let(:procedure) { create :simple_procedure, :with_service }
+
+    scenario 'a new user can sign-up and fill the procedure' do
+      visit commencer_path(path: procedure.path)
+
+      click_on 'Créer un compte'
+      expect(page).to have_current_path new_user_registration_path
+      expect(page).to have_procedure_description(procedure)
+
+      sign_up_with user_email, user_password
+      expect(page).to have_content "nous avons besoin de vérifier votre adresse #{user_email}"
+
+      click_confirmation_link_for(user_email, in_another_browser: true)
+
+      # After confirmation, the user is redirected to the procedure they were initially starting
+      # (even when confirming the account in another browser).
+      expect(page).to have_current_path(commencer_path(path: procedure.path))
+      expect(page).to have_content I18n.t('devise.confirmations.confirmed')
+      click_on 'Commencer la démarche'
+
+      expect(page).to have_current_path identite_dossier_path(procedure.reload.dossiers.last)
+      expect(page).to have_procedure_description(procedure)
+    end
+  end
+
+  context 'when the user is not confirmed yet' do
+    before do
+      create(:user, :unconfirmed, email: user_email, password: user_password)
+    end
+
+    scenario 'the email confirmation page is displayed' do
+      visit commencer_path(path: procedure.path)
+      click_on 'Créer un compte'
+
+      sign_up_with user_email, user_password
+
+      # The same page than for initial sign-ups is displayed, to avoid leaking informations
+      # about the account existence.
+      expect(page).to have_content "nous avons besoin de vérifier votre adresse #{user_email}"
+
+      # The confirmation email is sent again
+      confirmation_email = open_email(user_email)
+      expect(confirmation_email.body).to have_text('Pour activer votre compte')
+
+      click_confirmation_link_for(user_email, in_another_browser: true)
+
+      # After confirmation, the user is redirected to the procedure they were initially starting
+      # (even when confirming the account in another browser).
+      expect(page).to have_current_path(commencer_path(path: procedure.path))
+      expect(page).to have_content I18n.t('devise.confirmations.confirmed')
+      expect(page).to have_content 'Commencer la démarche'
+    end
+  end
+
+  context 'when the user already has a confirmed account' do
+    before do
+      create(:user, email: user_email, password: user_password)
+    end
+
+    scenario 'they get a warning email, containing a link to the procedure' do
+      visit commencer_path(path: procedure.path)
+      click_on 'Créer un compte'
+
+      sign_up_with user_email, user_password
+
+      # The same page than for initial sign-ups is displayed, to avoid leaking informations
+      # about the accound existence.
+      expect(page).to have_content "nous avons besoin de vérifier votre adresse #{user_email}"
+
+      # A warning email is sent
+      warning_email = open_email(user_email)
+      expect(warning_email.body).to have_text('Votre compte existe déjà')
+
+      # When clicking the main button, the user is redirected directly to
+      # the sign-in page for the procedure they were initially starting.
+      click_procedure_sign_in_link_for user_email
+
+      expect(page).to have_current_path new_user_session_path
+      expect(page).to have_procedure_description(procedure)
+    end
+  end
+end