Adding support to allow_nil option for delegate_method matcher

Appraisals

@@ -1,7 +1,7 @@
 ruby_version = Gem::Version.new(RUBY_VERSION + '')
 
 shared_dependencies = proc do
-  gem 'rspec-rails', '>= 3.2.0', '< 4'
+  gem 'rspec-rails', '>= 3.3.0', '< 4'
   gem 'shoulda-context', '~> 1.2.0'
   gem 'sqlite3', platform: :ruby
   gem 'pg', platform: :ruby

Gemfile

@@ -5,8 +5,8 @@ gem 'bundler', '~> 1.1'
 gem 'pry', github: 'pry/pry'
 gem 'pry-byebug'
 gem 'rake', '~> 10.0'
-gem 'rspec-core', '>= 3.2.0', '< 4'
-gem 'rspec-expectations', '>= 3.2.0', '< 4'
+gem 'rspec-core', '>= 3.3.0', '< 4'
+gem 'rspec-expectations', '>= 3.3.0', '< 4'
 
 # YARD
 gem 'yard'

Gemfile.lock

@@ -53,9 +53,6 @@ DEPENDENCIES
   pygments.rb
   rake (~> 10.0)
   redcarpet
-  rspec-core (>= 3.2.0, < 4)
-  rspec-expectations (>= 3.2.0, < 4)
+  rspec-core (>= 3.3.0, < 4)
+  rspec-expectations (>= 3.3.0, < 4)
   yard
-
-BUNDLED WITH
-   1.10.6

gemfiles/4.0.0.gemfile

@@ -7,13 +7,13 @@ gem "bundler", "~> 1.1"
 gem "pry", :github => "pry/pry"
 gem "pry-byebug"
 gem "rake", "~> 10.0"
-gem "rspec-core", ">= 3.2.0", "< 4"
-gem "rspec-expectations", ">= 3.2.0", "< 4"
+gem "rspec-core", ">= 3.3.0", "< 4"
+gem "rspec-expectations", ">= 3.3.0", "< 4"
 gem "yard"
 gem "redcarpet"
 gem "pygments.rb"
 gem "fssm"
-gem "rspec-rails", ">= 3.2.0", "< 4"
+gem "rspec-rails", ">= 3.3.0", "< 4"
 gem "shoulda-context", "~> 1.2.0"
 gem "sqlite3", :platform => :ruby
 gem "pg", :platform => :ruby

gemfiles/4.0.0.gemfile.lock

@@ -199,9 +199,9 @@ DEPENDENCIES
   rails (= 4.0.0)
   rake (~> 10.0)
   redcarpet
-  rspec-core (>= 3.2.0, < 4)
-  rspec-expectations (>= 3.2.0, < 4)
-  rspec-rails (>= 3.2.0, < 4)
+  rspec-core (>= 3.3.0, < 4)
+  rspec-expectations (>= 3.3.0, < 4)
+  rspec-rails (>= 3.3.0, < 4)
   sass-rails (~> 4.0.0)
   sdoc
   shoulda-context (~> 1.2.0)
@@ -212,6 +212,3 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   yard
-
-BUNDLED WITH
-   1.10.6

gemfiles/4.0.1.gemfile

@@ -7,13 +7,13 @@ gem "bundler", "~> 1.1"
 gem "pry", :github => "pry/pry"
 gem "pry-byebug"
 gem "rake", "~> 10.0"
-gem "rspec-core", ">= 3.2.0", "< 4"
-gem "rspec-expectations", ">= 3.2.0", "< 4"
+gem "rspec-core", ">= 3.3.0", "< 4"
+gem "rspec-expectations", ">= 3.3.0", "< 4"
 gem "yard"
 gem "redcarpet"
 gem "pygments.rb"
 gem "fssm"
-gem "rspec-rails", ">= 3.2.0", "< 4"
+gem "rspec-rails", ">= 3.3.0", "< 4"
 gem "shoulda-context", "~> 1.2.0"
 gem "sqlite3", :platform => :ruby
 gem "pg", :platform => :ruby

gemfiles/4.0.1.gemfile.lock

@@ -201,9 +201,9 @@ DEPENDENCIES
   rails (= 4.0.1)
   rake (~> 10.0)
   redcarpet
-  rspec-core (>= 3.2.0, < 4)
-  rspec-expectations (>= 3.2.0, < 4)
-  rspec-rails (>= 3.2.0, < 4)
+  rspec-core (>= 3.3.0, < 4)
+  rspec-expectations (>= 3.3.0, < 4)
+  rspec-rails (>= 3.3.0, < 4)
   sass-rails (~> 4.0.0)
   sdoc
   shoulda-context (~> 1.2.0)
@@ -214,6 +214,3 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   yard
-
-BUNDLED WITH
-   1.10.6

gemfiles/4.1.gemfile

@@ -7,13 +7,13 @@ gem "bundler", "~> 1.1"
 gem "pry", :github => "pry/pry"
 gem "pry-byebug"
 gem "rake", "~> 10.0"
-gem "rspec-core", ">= 3.2.0", "< 4"
-gem "rspec-expectations", ">= 3.2.0", "< 4"
+gem "rspec-core", ">= 3.3.0", "< 4"
+gem "rspec-expectations", ">= 3.3.0", "< 4"
 gem "yard"
 gem "redcarpet"
 gem "pygments.rb"
 gem "fssm"
-gem "rspec-rails", ">= 3.2.0", "< 4"
+gem "rspec-rails", ">= 3.3.0", "< 4"
 gem "shoulda-context", "~> 1.2.0"
 gem "sqlite3", :platform => :ruby
 gem "pg", :platform => :ruby

gemfiles/4.1.gemfile.lock

@@ -196,9 +196,9 @@ DEPENDENCIES
   rails (~> 4.1.0)
   rake (~> 10.0)
   redcarpet
-  rspec-core (>= 3.2.0, < 4)
-  rspec-expectations (>= 3.2.0, < 4)
-  rspec-rails (>= 3.2.0, < 4)
+  rspec-core (>= 3.3.0, < 4)
+  rspec-expectations (>= 3.3.0, < 4)
+  rspec-rails (>= 3.3.0, < 4)
   sass-rails (~> 4.0.3)
   sdoc (~> 0.4.0)
   shoulda-context (~> 1.2.0)
@@ -209,6 +209,3 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   yard
-
-BUNDLED WITH
-   1.10.6

gemfiles/4.2.gemfile

@@ -7,13 +7,13 @@ gem "bundler", "~> 1.1"
 gem "pry", :github => "pry/pry"
 gem "pry-byebug"
 gem "rake", "~> 10.0"
-gem "rspec-core", ">= 3.2.0", "< 4"
-gem "rspec-expectations", ">= 3.2.0", "< 4"
+gem "rspec-core", ">= 3.3.0", "< 4"
+gem "rspec-expectations", ">= 3.3.0", "< 4"
 gem "yard"
 gem "redcarpet"
 gem "pygments.rb"
 gem "fssm"
-gem "rspec-rails", ">= 3.2.0", "< 4"
+gem "rspec-rails", ">= 3.3.0", "< 4"
 gem "shoulda-context", "~> 1.2.0"
 gem "sqlite3", :platform => :ruby
 gem "pg", :platform => :ruby

gemfiles/4.2.gemfile.lock

@@ -219,9 +219,9 @@ DEPENDENCIES
   rails (~> 4.2.0)
   rake (~> 10.0)
   redcarpet
-  rspec-core (>= 3.2.0, < 4)
-  rspec-expectations (>= 3.2.0, < 4)
-  rspec-rails (>= 3.2.0, < 4)
+  rspec-core (>= 3.3.0, < 4)
+  rspec-expectations (>= 3.3.0, < 4)
+  rspec-rails (>= 3.3.0, < 4)
   sass-rails (~> 5.0)
   sdoc (~> 0.4.0)
   shoulda-context (~> 1.2.0)
@@ -232,6 +232,3 @@ DEPENDENCIES
   turbolinks
   uglifier (>= 1.3.0)
   yard
-
-BUNDLED WITH
-   1.10.6

lib/shoulda/matchers/independent/delegate_method_matcher.rb

@@ -180,7 +180,8 @@ def matches?(subject)
 
           subject_has_delegating_method? &&
             subject_has_delegate_object_reader_method? &&
-            subject_delegates_to_delegate_object_correctly?
+            subject_delegates_to_delegate_object_correctly? &&
+            subject_delegates_to_nil_delegate_object_correctly?
         end
 
         def description
@@ -191,6 +192,10 @@ def description
             string << " passing arguments #{delegated_arguments.inspect}"
           end
 
+          if delegate_object_is_nil_allowed
+            string << ' allowing nil'
+          end
+
           if delegate_method != delegating_method
             string << " as #{formatted_delegate_method}"
           end
@@ -220,6 +225,11 @@ def with_prefix(prefix = nil)
           self
         end
 
+        def allow_nil
+          @delegate_object_is_nil_allowed = true
+          self
+        end
+
         def build_delegating_method_prefix(prefix)
           case prefix
             when true, nil then delegate_object_reader_method
@@ -248,7 +258,8 @@ def failure_message_when_negated
           :delegate_method,
           :subject_double_collection,
           :delegate_object,
-          :delegate_object_reader_method
+          :delegate_object_reader_method,
+          :delegate_object_is_nil_allowed
 
         def subject
           @subject
@@ -328,8 +339,21 @@ def ensure_delegate_object_has_been_specified!
           end
         end
 
+        def subject_delegates_to_nil_delegate_object_correctly?
+          return true unless delegate_object_is_nil_allowed
+          register_subject_double_collection_to(nil)
+
+          Doublespeak.with_doubles_activated do
+            begin
+              subject.public_send(delegating_method, *delegated_arguments).nil?
+            rescue
+              false
+            end
+          end
+        end
+
         def subject_delegates_to_delegate_object_correctly?
-          register_subject_double_collection
+          register_subject_double_collection_to(delegate_object)
 
           Doublespeak.with_doubles_activated do
             subject.public_send(delegating_method, *delegated_arguments)
@@ -342,11 +366,11 @@ def subject_delegates_to_delegate_object_correctly?
           end
         end
 
-        def register_subject_double_collection
+        def register_subject_double_collection_to(returned_object)
           double_collection =
             Doublespeak.double_collection_for(subject.singleton_class)
           double_collection.register_stub(delegate_object_reader_method).
-            to_return(delegate_object)
+            to_return(returned_object)
 
           @subject_double_collection = double_collection
         end

spec/unit/shoulda/matchers/independent/delegate_method_matcher_spec.rb

@@ -514,4 +514,109 @@ def country
       end
     end
   end
+
+  context 'qualified with #allow_nil' do
+    context 'when using delegate from rails' do
+      context 'when delegate call allows 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 delegate call does not allow nil' do
+        it 'rejects with the correct failure message' do
+          define_class('Person') do
+            delegate :hello, to: :country
+            def country; end
+          end
+
+          message = [
+            'Expected Person to delegate #hello to #country'\
+            ' object allowing nil',
+            'Method calls sent to Person#country:',
+          ].join("\n")
+
+          person = Person.new
+
+          expect do
+            expect(person).to delegate_method(:hello).to(:country).allow_nil
+          end.to fail_including(message)
+        end
+      end
+    end
+    context 'when using Forwardable' do
+      context 'when 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
+
+          message = [
+            'Expected Person to delegate #hello to #country'\
+            ' object allowing nil',
+            'Method calls sent to Person#country:',
+            '1) hello()',
+          ].join("\n")
+
+          person = Person.new
+
+          expect do
+            expect(person).to delegate_method(:hello).to(:country).allow_nil
+          end.to fail_with_message(message)
+        end
+      end
+    end
+    context 'when using methods' do
+      context 'when supports nil delegate object' 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 does not supports nil delegate object' do
+        it 'rejects with the correct failure message' do
+          define_class('Person') do
+            def country; end
+
+            def hello
+              country.hello
+            end
+          end
+
+          message = [
+            'Expected Person to delegate #hello to #country'\
+            ' object allowing nil',
+            'Method calls sent to Person#country:',
+            '1) hello()',
+          ].join("\n")
+
+          person = Person.new
+
+          expect do
+            expect(person).to delegate_method(:hello).to(:country).allow_nil
+          end.to fail_with_message(message)
+        end
+      end
+    end
+  end
 end

spec/unit_spec_helper.rb

@@ -14,6 +14,7 @@
 ENV['RAILS_ENV'] = 'test'
 
 require 'rspec/rails'
+require 'rspec/matchers/fail_matchers'
 require 'shoulda-matchers'
 
 PROJECT_ROOT = File.expand_path('../..', __FILE__)
@@ -59,6 +60,7 @@
   UnitTests::ColumnTypeHelpers.configure_example_group(config)
 
   config.include UnitTests::Matchers
+  config.include RSpec::Matchers::FailMatchers
 end
 
 ActiveSupport::Deprecation.behavior = :stderr