Avoid code duplication in Rspec + Capybara - ruby-on-rails

Question

Let's say I have test on new input and test on new input when input is invalid (first test is on case input is valid).
For example (from my code):
scenario "valid input saving" do
visit program_stream_path(#program, #stream)
click_link "#link"
fill_in "#fill_in", :with=>"1"
click_button "Next"
expect(page).to have_current_path new_students_list_stream_path(#stream)
within("#student_0") do
fill_in "Имя", :with => "Name"
fill_in "Фамилия", :with => "Surname"
fill_in "Электронная почта", :with => "randommail#mail.com"
end
print page.html
click_button "Save"
expect(page).to have_current_path program_stream_path(#program, #stream)
#...other code
end
Obviously, test that checks behavior on invalid input repeats this part:
scenario "invalid input leads to correct input page" do
visit program_stream_path(#program, #stream)
click_link "#link"
fill_in "#fill_in", :with=>"1"
click_button "Next"
expect(page).to have_current_path new_students_list_stream_path(#stream)
#other code
How to avoid this copy-paste way?

Answer 1

You can use before blocks for this kind of thing
feature "..." do
before :each do
visit program_stream_path(#program, #stream)
click_link "#link"
fill_in "#fill_in", :with=>"1"
click_button "Next"
expect(page).to have_current_path new_students_list_stream_path(#stream)
end
scenario "valid input saving"
#unique code for this scenario
end
scenario "invalid input leads to correct input page"
# unique code for this scenario
end
end
The outer feature block could be a describe or a scenario block if wanted/needed since you can nest multiple levels. If you need to use the code across multiple feature files then it makes sense to move it to a method in one of your spec helper files.

Answer 2

You can place it in a method in your spec file like this and reuse it.
scenario "valid input saving" do
your_named_method
...
end
scenario "invalid input leads to correct input page" do
your_named_method
...
end
def your_named_method
visit program_stream_path(#program, #stream)
click_link "#link"
fill_in "#fill_in", :with=>"1"
click_button "Next"
expect(page).to have_current_path new_students_list_stream_path(#stream)
end

Answer 3

A great way to avoid duplication when testing with Capybara is to use Capybara Test Helpers.
RSpec.feature 'Program Stream', test_helpers: [:programs] do
before { visit program_stream_path(#program, #stream) }
scenario 'valid input saving' do
programs.click_to_add_student
programs.should.be_adding_a_student(#stream)
programs.add_student(name: 'Имя', surname: 'Фамилия', email: 'randommail#mail.com')
programs.should.have_new_student('Имя')
end
scenario 'invalid input leads to correct input page' do
programs.click_to_add_student
programs.should.be_adding_a_student(#stream)
programs.add_student(name: nil, surname: nil, email: nil)
programs.should.have_invalid_form("Name can't be blank")
end
end
Besides reducing code duplication, it has the benefit of being a lot more descriptive, which can help to make tests a lot easier to maintain in the long term.
class ProgramsTestHelper < Capybara::TestHelper
# Actions: Encapsulate complex actions to provide a cleaner interface.
def click_to_add_student
click_link '#link'
fill_in '#fill_in', with: '1')
click_button "Next"
end
def add_student(name:, surname:, email:)
fill_in 'Имя', with: name
fill_in 'Фамилия', with: surname
fill_in 'Электронная почта', with: email
click_button 'Save'
end
# Assertions: Allow to check on element properties while keeping it DRY.
def be_adding_a_student(stream)
have_current_path urls.new_students_list_stream_path(stream)
end
def have_new_student(name)
have_content(name)
end
def have_invalid_form(message)
have('form', text: message)
end
end
Have in mind that you could choose to combine click_to_add_student with add_student, running assertions inside the helper methods. It all boils down to how much granularity you need in tests.
Passing blocks to methods is also a nice way to customize interactions or outcomes.