Mock Implementations of RSpec components.

mock_example_group.rb

module Spec::Support
  class ExampleGroup
    class << self
      attr_reader :description

      def describe description
        example_group = Class.new(self)

        example_group.description = description

        children << example_group

        example_group
      end # class method describe

      def inspect
        return 'Spec::Support::ExampleGroup' if description.nil?

        "Spec::Support::ExampleGroup(description=\"#{description}\")"
      end # class method inspect

      def it description, &block

      end # class method it

      protected

      attr_writer :description

      def children
        @children ||= []
      end # class method children

      def examples
        @examples = []
      end # class method examples
    end # eigenclass
  end # class
end # module

shared_examples_spec.rb

# tmp/shared_examples_spec.rb

require 'sleeping_king_studios/tools/toolbox/mixin'

require 'rspec/sleeping_king_studios/concerns/wrap_examples'

module SharedExamples
  extend SleepingKingStudios::Tools::Toolbox::Mixin

  def self.included other
    super

    mixin_module = SleepingKingStudios::Tools::Toolbox::Mixin

    return if other.is_a?(Class) || other.ancestors.include?(mixin_module)

    other.extend(mixin_module)
  end # method included

  module ClassMethods
    def include_examples description, *args, &block
      shared = find_shared_examples(description)

      if shared
        instance_exec(*args, &shared)

        instance_exec(&block) if block_given?

        return
      end # if

      super
    end # class method include_examples

    def shared_examples description, &block
      shared_example_groups[description] = block
    end # class method shared_examples

    protected

    def shared_example_groups
      @shared_example_groups ||= {}
    end # class method shared_example_groups

    private

    def find_shared_examples description
      ancestors.
        select { |mod| mod < SharedExamples }.
        each do |mod|
          next unless mod.shared_example_groups.key?(description)

          return mod.shared_example_groups[description]
        end # each

      nil
    end # class method find_shared_examples
  end # module
end # module

module ObjectExamples
  include SharedExamples

  shared_examples 'should be a' do |klass|
    it { expect(instance).to be_a klass }
  end # shared_examples
end # module

module StringExamples
  include SharedExamples

  shared_examples 'should be a string' do
    it { expect(instance).to be_a String }
  end # shared_examples
end # module

module GreetingExamples
  include SharedExamples
  include StringExamples

  shared_examples 'should be a greeting' do
    it { expect(instance).to start_with('Greetings') }
  end # shared_examples
end # module

RSpec.describe 'default RSpec' do
  shared_examples 'should be a greeting' do
    it { expect(instance).to start_with('Greetings') }
  end # shared_examples

  subject(:instance) { 'Greetings, programs!' }

  include_examples 'should be a greeting'

  describe 'failing examples' do
    include_examples 'should be a greeting' do
      let(:instance) { 'Hello, world!' }
    end # include_examples
  end # describe
end # describe

RSpec.describe SharedExamples do
  include ObjectExamples
  include GreetingExamples

  subject(:instance) { 'Greetings, programs!' }

  include_examples 'should be a', String

  include_examples 'should be a string'

  include_examples 'should be a greeting'

  describe 'failing examples' do
    include_examples 'should be a greeting' do
      let(:instance) { 'Hello, world!' }
    end # include_examples
  end # describe

  describe 'wrapping examples' do
    extend RSpec::SleepingKingStudios::Concerns::WrapExamples

    wrap_examples 'should be a greeting'

    wrap_examples 'should be a greeting' do
      let(:instance) { 'Hello, world!' }
    end # wrap_examples
  end # describe
end # describe