RSpec/Capybara tests
Some comments:


Rspec expects the concatenation of feature and `scenario to form a human readable text.
AFAIK, the orthodoox structure for specs is to perform the actions in the before block and only assertions in it blocks.
Use before blocks to keep your code DRY.
Personal opinion: in a feature spec, the less app internals you use, the better. So I'd write "/" instead of root_path. 
The user/password info a in the factory, I'd prefer explicit attributes on the creation.


That's how I'd write the Login feature, the same ideas apply for Signup:

feature 'Login' do
  before do
    FactoryGirl.create(:user, :email =&gt; "test@example.com", :password =&gt; "password")
    visit root_path
    click_link 'Login'
  end

  scenario "with valid user/password", js: true do
    before do
      fill_in 'email', :with =&gt; 'test@example.com'
      fill_in 'password', :with =&gt; 'password'
      click_button 'Login'
    end

    it "shows the logged in message" do
      expect(page).to have_content('Logged in successfully')
    end
  end

  scenario "with wrong user/password", js: true do
    before do
      fill_in 'email', :with =&gt; 'failed@login.com'
      fill_in 'password', :with =&gt; 'something failed'
      click_button 'Login'
    end

    it "shows an error message" do
      expect(page).to have_content('Invalid login/password combination')
    end
  end
end