RSpec Setup and TDD concepts from https://code.tutsplus.com/articles/rspec-testing-for-beginners-part-1--cms-26716

RSpec_TDD_Tutorial_1.md

RSpec TDD Tutorial

From this tutorial

1. Set up new Rails app. -T flag skips installation of MiniTest:

$ rails new my_app -T

2. Add RSpec to Gemfile.rb:

group :development, :test do
  gem 'rspec-rails'
end

3. Bundle install: bundle

4. Install RSpec files: rails g rspec:install

5. When you generate a model, controller, etc., a spec will also be generated. Example:

$ rails g model User name:string email:string

6. Set up the test and dev databases:

$ rails db: migrate
$ rails db:test:prepare

7. To run all tests: $ bundle exec rspec or $ rake. To run one set: $ bundle exec spec/models. To run one set of tests: $ bundle exec spec/models/user_spec.rb. To run one tests: $ bundle exec spec/model/user_spec.rb:20

Testing Syntax

1. describe : Scopes parts of the app to test, can take class name or string:

describe User do
 
end

As class grows, class name can be followed by a string to restrict scope to certain methods:

describe Agent, '#favorite_gadget' do
  ...
end
 
describe Agent, '#favorite_gun' do
  ...
end
 
describe Agent, '.gambler' do
  ...
end

2. it blocks are the individual descriptions, testing units.

describe Agent, '#favorite_gadget' do
 
  it 'returns one item, the favorite gadget of the agent ' do
    ...
  end
 
end

3. expect() Lets you verify or falsify parts of the system

describe Agent, '#favorite_gadget' do
 
  it 'returns one item, the favorite gadget of the agent ' do
    expect(agent.favorite_gadget).to eq 'Walther PPK'
  end
 
end

4. Four phases of a test:

• Setup . - Prepare the data
• Exercise - Run the method you want to test
• Verification . - Verify the assertion is met
• Teardown . - (Usually handled by RSpec itself)

Matchers

• .to eq()
• .not_to eq()
• .to be true
• .to be_truthy
• .to be false
• .to be_falsy
• .to be_nil
• .not_to be_nil  * .to match() . : Useful for REGEX

Error matchers:

• .to raise_error
• .to raise_error(ErrorClass)
• .to raise_error(ErrorClass, "Some error message")
• .to raise_error("Some error message)

Callbacks

• before(:each) do /../ end Runs a series of initializers or methods before running tests:

describe Agent, '#favorite_gadget' do
 
  before(:each) do
    @gagdet = Gadget.create(name: 'Walther PPK')
  end
 
  it 'returns one item, the favorite gadget of the agent ' do
    agent = Agent.create(name: 'James Bond')
    agent.favorite_gadgets << @gadget
 
    expect(agent.favorite_gadget).to eq 'Walther PPK'
  end
 
  ...
 
end

• before(:all) . Runs once before all of the tests in a scope.