delegate_method_matcher_spec.rb

require 'unit_spec_helper'

describe Shoulda::Matchers::Independent::DelegateMethodMatcher do
  describe '#description' do
    context 'when the subject is an instance' do
      subject { Object.new }

      context 'without any qualifiers' do
        it 'states that it should delegate method to the right object' do
          matcher = delegate_method(:method_name).to(:delegate)
          message = 'delegate #method_name to the #delegate object'

          expect(matcher.description).to eq message
        end
      end

      context 'qualified with #as' do
        it 'states that it should delegate method to the right object and method' do
          matcher = delegate_method(:method_name).to(:delegate).as(:alternate)
          message = 'delegate #method_name to the #delegate object as #alternate'

          expect(matcher.description).to eq message
        end
      end

      context 'qualified with #with_arguments' do
        it 'states that it should delegate method to the right object with right argument' do
          matcher = delegate_method(:method_name).to(:delegate).
            with_arguments(:foo, bar: [1, 2])
          message = 'delegate #method_name to the #delegate object passing arguments [:foo, {:bar=>[1, 2]}]'

          expect(matcher.description).to eq message
        end
      end

      context 'qualified with #with_prefix' do
        context 'without arguments' do
          before do
            define_model('Country') do
              def hello; 'hello' end
            end
          end

          context "when the subject's delegating method also has a prefix" do
            it 'produces the correct description' do
              define_class('Person') do
                delegate :hello, to: :country, prefix: true

                def country
                  Country.new
                end
              end

              matcher = delegate_method(:hello).to(:country).with_prefix
              expect(matcher.description).
                to eq('delegate #country_hello to the #country object as #hello')
            end
          end
        end

        context 'as true' do
          before do
            define_model('Country') do
              def hello; 'hello' end
            end
          end

          context "when the subject's delegating method also has a prefix" do
            it 'produces the correct description' do
              define_class('Person') do
                delegate :hello, to: :country, prefix: true

                def country
                  Country.new
                end
              end

              matcher = delegate_method(:hello).to(:country).with_prefix(true)
              expect(matcher.description).
                to eq('delegate #country_hello to the #country object as #hello')
            end
          end
        end

        context 'as a symbol/string' do
          it 'should delegate as (prefix_supplied)_(method_on_target)' do
            define_model('Country') do
              def hello; 'hello' end
            end

            define_class('Person') do
              delegate :hello, to: :country, prefix: 'county'

              def country
                Country.new
              end
            end

            matcher = delegate_method(:hello).to(:country).with_prefix('county')
            expect(matcher.description).
              to eq('delegate #county_hello to the #country object as #hello')
          end
        end
      end
    end

    context 'when the subject is a class' do
      subject { Object }

      context 'without any qualifiers' do
        it 'states that it should delegate method to the right object' do
          matcher = delegate_method(:method_name).to(:delegate)

          expect(matcher.description).
            to eq 'delegate .method_name to the .delegate object'
        end
      end

      context 'qualified with #as' do
        it 'states that it should delegate method to the right object and method' do
          matcher = delegate_method(:method_name).to(:delegate).as(:alternate)
          message = 'delegate .method_name to the .delegate object as .alternate'

          expect(matcher.description).to eq message
        end
      end

      context 'qualified with #with_arguments' do
        it 'states that it should delegate method to the right object with right argument' do
          matcher = delegate_method(:method_name).to(:delegate).
            with_arguments(:foo, bar: [1, 2])
          message = 'delegate .method_name to the .delegate object passing arguments [:foo, {:bar=>[1, 2]}]'

          expect(matcher.description).to eq message
        end
      end
    end
  end

  it 'raises an error if the delegate object was never specified before matching' do
    expect {
      expect(Object.new).to delegate_method(:name)
    }.to raise_error described_class::DelegateObjectNotSpecified
  end

  context 'stubbing a delegating method on an instance' do
    it 'only happens temporarily and is removed after the match' do
      define_class('Company') do
        def name
          'Acme Company'
        end
      end

      define_class('Person') do
        def company_name
          company.name
        end

        def company
          Company.new
        end
      end

      person = Person.new
      matcher = delegate_method(:company_name).to(:company).as(:name)
      matcher.matches?(person)

      expect(person.company.name).to eq 'Acme Company'
    end
  end

  context 'when the subject does not delegate anything' do
    before do
      define_class('PostOffice')
    end

    context 'when the subject is an instance' do
      it 'rejects with the correct failure message' do
        post_office = PostOffice.new
        message = [
          'Expected PostOffice to delegate #deliver_mail to the #mailman object.',
          '',
          'Method calls sent to PostOffice#mailman: (none)'
        ].join("\n")

        expect {
          expect(post_office).to delegate_method(:deliver_mail).to(:mailman)
        }.to fail_with_message(message)
      end
    end

    context 'when the subject is a class' do
      it 'uses the proper syntax for class methods in errors' do
        message = [
          'Expected PostOffice to delegate .deliver_mail to the .mailman object.',
          '',
          'Method calls sent to PostOffice.mailman: (none)'
        ].join("\n")

        expect {
          expect(PostOffice).to delegate_method(:deliver_mail).to(:mailman)
        }.to fail_with_message(message)
      end
    end
  end

  context 'when the subject delegates correctly' do
    before do
      define_class('Mailman')

      define_class('PostOffice') do
        def deliver_mail
          mailman.deliver_mail
        end

        def mailman
          Mailman.new
        end
      end
    end

    it 'accepts' do
      post_office = PostOffice.new
      expect(post_office).to delegate_method(:deliver_mail).to(:mailman)
    end

    context 'negating the matcher' do
      it 'rejects with the correct failure message' do
        post_office = PostOffice.new
        message = 'Expected PostOffice not to delegate #deliver_mail to the #mailman object, but it did.'

        expect {
          expect(post_office).not_to delegate_method(:deliver_mail).to(:mailman)
        }.to fail_with_message(message)
      end
    end
  end

  context 'when the delegating method is private' do
    before do
      define_class('Mailman')

      define_class('PostOffice') do
        def deliver_mail
          mailman.deliver_mail
        end

        def mailman
          Mailman.new
        end

        private :mailman
      end
    end

    it 'accepts' do
      post_office = PostOffice.new
      expect(post_office).to delegate_method(:deliver_mail).to(:mailman)
    end
  end

  context 'qualified with #with_arguments' do
    before do
      define_class('Mailman')

      define_class('PostOffice') do
        def deliver_mail(*args)
          mailman.deliver_mail('221B Baker St.', hastily: true)
        end

        def mailman
          Mailman.new
        end
      end
    end

    context 'qualified with #with_arguments' do
      context 'when the subject delegates with matching arguments' do
        it 'accepts' do
          post_office = PostOffice.new
          expect(post_office).to delegate_method(:deliver_mail).
            to(:mailman).with_arguments('221B Baker St.', hastily: true)
        end

        context 'negating the matcher' do
          it 'rejects with the correct failure message' do
            post_office = PostOffice.new
            message = 'Expected PostOffice not to delegate #deliver_mail to the #mailman object passing arguments ["221B Baker St.", {:hastily=>true}], but it did.'

            expect {
              expect(post_office).
                not_to delegate_method(:deliver_mail).
                to(:mailman).
                with_arguments('221B Baker St.', hastily: true)
            }.to fail_with_message(message)
          end
        end
      end

      context 'when not given the correct arguments' do
        it 'rejects with the correct failure message' do
          post_office = PostOffice.new
          message = [
            'Expected PostOffice to delegate #deliver_mail to the #mailman object',
            'passing arguments ["123 Nowhere Ln."].',
            '',
            'Method calls sent to PostOffice#mailman:',
            '',
            '1) deliver_mail("221B Baker St.", {:hastily=>true})'
          ].join("\n")

          expect {
            expect(post_office).to delegate_method(:deliver_mail).
              to(:mailman).with_arguments('123 Nowhere Ln.')
          }.to fail_with_message(message)
        end
      end
    end
  end

  context 'qualified with #as' do
    before do
      define_class(:mailman)

      define_class(:post_office) do
        def deliver_mail
          mailman.deliver_mail_and_avoid_dogs
        end

        def mailman
          Mailman.new
        end
      end
    end

    context "when the given method is the same as the subject's delegating method" do
      it 'accepts' do
        post_office = PostOffice.new
        expect(post_office).to delegate_method(:deliver_mail).
          to(:mailman).as(:deliver_mail_and_avoid_dogs)
      end

      context 'negating the assertion' do
        it 'rejects with the correct failure message' do
          post_office = PostOffice.new
          message = 'Expected PostOffice not to delegate #deliver_mail to the #mailman object as #deliver_mail_and_avoid_dogs, but it did.'

          expect {
            expect(post_office).
              not_to delegate_method(:deliver_mail).
              to(:mailman).
              as(:deliver_mail_and_avoid_dogs)
          }.to fail_with_message(message)
        end
      end
    end

    context "when the given method is not the same as the subject's delegating method" do
      it 'rejects with the correct failure message' do
        post_office = PostOffice.new
        message = [
          'Expected PostOffice to delegate #deliver_mail to the #mailman object as',
          '#watch_tv.',
          '',
          'Method calls sent to PostOffice#mailman:',
          '',
          '1) deliver_mail_and_avoid_dogs()'
        ].join("\n")

        expect {
          expect(post_office).to delegate_method(:deliver_mail).
            to(:mailman).as(:watch_tv)
        }.to fail_with_message(message)
      end
    end
  end

  context 'qualified with #with_prefix' do
    context 'without arguments' do
      before do
        define_model('Country') do
          def hello; 'hello' end
        end
      end

      context "when the subject's delegating method also has a prefix" do
        it 'accepts' do
          define_class('Person') do
            delegate :hello, to: :country, prefix: true

            def country
              Country.new
            end
          end

          person = Person.new
          expect(person).to delegate_method(:hello). to(:country).with_prefix
        end
      end

      context "when the subject's delegating method does not have a prefix" do
        it 'rejects with the correct failure message' do
          define_class('Person') do
            delegate :hello, to: :country

            def country
              Country.new
            end
          end

          message = [
            'Expected Person to delegate #country_hello to the #country object as',
            '#hello.',
            '',
            'Method calls sent to Person#country: (none)'
          ].join("\n")

          person = Person.new

          expect {
            expect(person).to delegate_method(:hello).to(:country).with_prefix
          }.to fail_with_message(message)
        end
      end
    end

    context 'as true' do
      before do
        define_model('Country') do
          def hello; 'hello' end
        end
      end

      context "when the subject's delegating method also has a prefix" do
        it 'accepts' do
          define_class('Person') do
            delegate :hello, to: :country, prefix: true

            def country
              Country.new
            end
          end

          person = Person.new
          expect(person).
            to delegate_method(:hello).
            to(:country).with_prefix(true)
        end
      end

      context "when the subject's delegating method does not have a prefix" do
        it 'rejects with the correct failure message' do
          define_class('Person') do
            delegate :hello, to: :country

            def country
              Country.new
            end
          end

          message = [
            'Expected Person to delegate #country_hello to the #country object as',
            '#hello.',
            '',
            'Method calls sent to Person#country: (none)'
          ].join("\n")

          person = Person.new

          expect {
            expect(person).
              to delegate_method(:hello).
              to(:country).with_prefix(true)
          }.to fail_with_message(message)
        end
      end
    end

    context 'as a symbol/string' do
      before do
        define_model('Country') do
          def hello; 'hello' end
        end
      end

      context "when the subject's delegating method has the same prefix" do
        it 'accepts' do
          define_class('Person') do
            delegate :hello, to: :country, prefix: 'county'

            def country
              Country.new
            end
          end

          person = Person.new
          expect(person).
            to delegate_method(:hello).
            to(:country).with_prefix('county')
        end
      end

      context "when the subject's delegating method has a different prefix" do
        it 'rejects with the correct failure message' do
          define_class('Person') do
            delegate :hello, to: :country, prefix: 'something_else'

            def country
              Country.new
            end
          end

          message = [
            'Expected Person to delegate #county_hello to the #country object as',
            '#hello.',
            '',
            'Method calls sent to Person#country: (none)'
          ].join("\n")

          person = Person.new

          expect {
            expect(person).
              to delegate_method(:hello).
              to(:country).with_prefix('county')
          }.to fail_with_message(message)
        end
      end
    end
  end

  context 'qualified with #allow_nil' do
    context 'when using delegate from Rails' do
      context 'when delegations were defined with :allow_nil' do
        it 'accepts' do
          define_class('Person') do
            delegate :hello, to: :country, allow_nil: true
            def country; end
          end

          person = Person.new

          expect(person).to delegate_method(:hello).to(:country).allow_nil
        end
      end

      context 'when delegations were not defined with :allow_nil' do
        it 'rejects with the correct failure message' do
          define_class('Person') do
            delegate :hello, to: :country
            def country; end
          end

          person = Person.new

          message = <<-MESSAGE
Expected Person to delegate #hello to the #country object, allowing
#country to return nil.

Person#hello did delegate to #country when it was non-nil, but it failed
to account for when #country *was* nil.
          MESSAGE

          expectation = lambda do
            expect(person).to delegate_method(:hello).to(:country).allow_nil
          end

          expect(&expectation).to fail_with_message(message)
        end
      end
    end

    context 'when using Forwardable' do
      context 'when the delegate object is nil' do
        it 'rejects with the correct failure message' do
          define_class('Person') do
            extend Forwardable

            def_delegators :country, :hello

            def country; end
          end

          person = Person.new

          message = <<-MESSAGE
Expected Person to delegate #hello to the #country object, allowing
#country to return nil.

Person#hello did delegate to #country when it was non-nil, but it failed
to account for when #country *was* nil.
          MESSAGE

          expectation = lambda do
            silence_warnings do
              expect(person).to delegate_method(:hello).to(:country).allow_nil
            end
          end

          expect(&expectation).to fail_with_message(message)
        end
      end
    end

    context 'when delegating manually' do
      context 'when the delegating method accounts for the delegate object being nil' do
        it 'accepts' do
          define_class('Person') do
            def country; end

            def hello
              return unless country
              country.hello
            end
          end

          person = Person.new

          expect(person).to delegate_method(:hello).to(:country).allow_nil
        end
      end

      context 'when the delegating method does not account for the delegate object being nil' do
        it 'rejects with the correct failure message' do
          define_class('Person') do
            def country; end

            def hello
              country.hello
            end
          end

          person = Person.new

          message = <<-MESSAGE
Expected Person to delegate #hello to the #country object, allowing
#country to return nil.

Person#hello did delegate to #country when it was non-nil, but it failed
to account for when #country *was* nil.
          MESSAGE

          expectation = lambda do
            expect(person).to delegate_method(:hello).to(:country).allow_nil
          end

          expect(&expectation).to fail_with_message(message)
        end
      end
    end
  end
end