Add acceptance test to check if the user password persists after form redisplays.

- While signing up.

spec/features/signup_spec.rb

+require 'spec_helper'
+
+feature 'Signup', feature: true do
+  describe 'signup with no errors' do
+    it 'creates the user account and sends a confirmation email' do
+      user = build(:user)
+
+      visit root_path
+
+      fill_in 'user_name',                with: user.name
+      fill_in 'user_username',            with: user.username
+      fill_in 'user_email',               with: user.email
+      fill_in 'user_password_sign_up',    with: user.password
+      click_button "Sign up"
+
+      expect(current_path).to eq user_session_path
+      expect(page).to have_content("A message with a confirmation link has been sent to your email address.")
+    end
+  end
+
+  describe 'signup with errors' do
+    it "displays the errors" do
+      existing_user = create(:user)
+      user = build(:user)
+
+      visit root_path
+
+      fill_in 'user_name',                with: user.name
+      fill_in 'user_username',            with: user.username
+      fill_in 'user_email',               with: existing_user.email
+      fill_in 'user_password_sign_up',    with: user.password
+      click_button "Sign up"
+
+      expect(current_path).to eq user_registration_path
+      expect(page).to have_content("error prohibited this user from being saved")
+      expect(page).to have_content("Email has already been taken")
+    end
+
+    it 'does not redisplay the password' do
+      existing_user = create(:user)
+      user = build(:user)
+
+      visit root_path
+
+      fill_in 'user_name',                with: user.name
+      fill_in 'user_username',            with: user.username
+      fill_in 'user_email',               with: existing_user.email
+      fill_in 'user_password_sign_up',    with: user.password
+      click_button "Sign up"
+
+      expect(current_path).to eq user_registration_path
+      expect(page.body).not_to match(/#{user.password}/)
+    end
+  end
+end