RSpec cheatsheet

 install rspec-rails gem only, it will install all the rspec related gems.

Basic setup steps

Step1:

gem 'rspec-rails'

root@f79191f58a4f:~# gem list rspec

*** LOCAL GEMS ***

rspec-core (3.9.3)

rspec-expectations (3.9.4)

rspec-mocks (3.9.1)

rspec-rails (3.9.1)

rspec-support (3.9.4)

Step2:

rails generate rspec:install

it will create 3 files,

.rspec

spec/rails_helper.rb

spec/spec_helper.rb

Step3:

put these two lines in the .rspec file,

--require spec_helper

--format documentation

Step4: 

run rspec as,

rspec

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Basic knowledge

All the spec(specification) files stay inside spec folder.
Allthe spec file ends with *_spec.rb
Example - spec/sales_spec.rb

All files in this directory(spec/**/*_spec.rb)will be run automatically when we run, 
rspec

Dry run spec as,
rspec --dry-run

Run a particular spec,
rspec spec/sales_spec.rb

Run a particular spec from a particular line,
rspec spec/coffee_spec.rb:31

Run rspec with formatted output as,
rspec --format doc 

'describe' is used to group 'it'

RSpec.describe 'An good sales' do
  it 'is not fare deal' do
    expect(sale_price).to eq(cost_price)
  end
end

This is called Assertion,
expect(sale_price).to eq(cost_price)

To share common code we use before, let, helper method.
let execute only ones.
helper_method execute on each call.
before execute just before every 'it'
context is used to group similar test.

describe -> before, let, helper method, it, context -> before,it

RSpec.describe 'A coffee' do
  let(:user_name) { User.new('Aarav Sharma') }
  it 'has name' do
    expect(user_name).to eq('Aarav Sharma')
  end

  context 'User info' do
    before { user_name.upcase }
    it 'has captial name' do
      expect(user_name).to eq('AARAV SHARMA')
    end
  end
end

Run a specific test,
rspec spec/controllers/systems_controller_spec.rb -e 'should display list of audit trails related to system'

RSpec hook - before, around etc.