Ruby rspec

rspec is a testing framework for ruby.

It grew out of behaviour-driven-development.

rspec naming conventions deviate from the norm.

Documentation

official docs

https://rspec.info/documentation/

Install

gem install rspec

Example

cd yourproject
rspec --init     # create new testproject

# spec/lib/mymodule_spec.rb
require "rspec"

describe MyClass do                  # tests for 'MyClass'

  # it defines a test
  it "is named Foo"                  # name of test
    myclass = MyClass.new            # ...contents...
    myclass.name.should == 'Foo'
  end

  # xit defines a pending test
  # (does not show false, shows pending)
  xit "is truthy"
end

# lib/mymodule.rb

class MyClass
  attr_accessor :name

  def initialize
    @name = 'Foo'
  end
end

Syntax

subject/described_class

If an object is passed to describe, it does not need to be instantiated, and is available magically with keyword subject.

describe MyClass
  it 'returns true' do
    subject.val.should eq(true)
  end
end

Alternatively, you can refer to the described class as described_class.

describe MyClass
  it 'is over 9000' do
    instance = described_class.new(rating: 9001)
    expect(instance.rating).to > 9000
  end
end

method tests

describe MyClass

  # tests on instance methods
  describe '#instance_method'
    it 'returns true' do
      # ..
    end
  end

  # tests on class methods
  describe '.class_method'
    it 'returns true' do
      # ..
    end
  end
end

context

context is simply a way of grouping tests under a label when a particular condition is true.

describe Dog
  context 'when age > 10' do
    it 'is sleepy after two hours' do
      dog = Dog.new(age: 15)
      expect(dog).to be_sleepy
    end
  end

  context 'when age < 2'
    it 'is not sleepy before 10 hours' do
      dog = Dog.new(age: 1)
      expect(dog).not_to be_sleepy
    end
  end
end