Add to_enum to the list of defined explicit conversions

.rspec

@@ -0,0 +1,2 @@
+--color
+--order random

.travis.yml

@@ -1,6 +1,7 @@
 bundler_args: --without development
 language: ruby
 rvm:
+  - 1.9.3
   - 2.0.0
   - 2.1.0
   - ruby-head

Changelog.md

@@ -3,4 +3,4 @@
 Features:
 
   - New "pebble" mode (Guilherme Carvalho)
-      
+

Gemfile

@@ -7,12 +7,14 @@ gem 'rake'
 
 group :development do
   gem 'guard'
-  gem 'guard-rspec'
   gem 'guard-bundler'
+  gem 'guard-rspec'
+  gem 'pry'
+  gem 'pry-rescue'
 end
 
 group :test do
-  gem "libnotify"
   gem 'coveralls', require: false
+  gem 'libnotify'
   gem 'rspec', '~> 2.14'
 end

README.markdown

@@ -133,6 +133,7 @@ null.to_a                          # => []
 null.to_h                          # => {}
 null.to_c                          # => (0+0i)
 null.to_r                          # => (0/1)
+null.to_enum                       # => #<Enumerator: nil:each>
 ```
 
 #### Ah, but what about implicit conversions such as `#to_str`? Like what if I want a null object that implicitly splats the same way as an empty array?
@@ -176,8 +177,8 @@ null_io = NullIO.new
 
 null_io << "foo"                # => nil
 null_io.readline                # => nil
-null_io.foobar                  # => 
-# ~> -:11:in `<main>': undefined method `foobar' for 
+null_io.foobar                  # =>
+# ~> -:11:in `<main>': undefined method `foobar' for
 #  <null:IO>:NullIO (NoMethodError)
 ```
 
@@ -245,8 +246,8 @@ null = NullObject.instance
 
 null.__id__                     # => 17844080
 NullObject.instance.__id__      # => 17844080
-NullObject.new                  # => 
-# ~> -:11:in `<main>': private method `new' called for 
+NullObject.new                  # =>
+# ~> -:11:in `<main>': private method `new' called for
 #  NullObject:Class (NoMethodError)
 ```
 
@@ -280,7 +281,7 @@ NullObject = Naught.build do |config|
   else
     config.singleton
   end
-end  
+end
 ```
 
 The only caveat is that when swapping between singleton and

lib/naught/null_class_builder/commands/define_explicit_conversions.rb

@@ -7,7 +7,7 @@ def call
       defer do |subject|
         subject.module_eval do
           extend Forwardable
-          def_delegators :nil, :to_a, :to_c, :to_f, :to_h, :to_i, :to_r, :to_s
+          def_delegators :nil, :to_a, :to_c, :to_enum, :to_f, :to_h, :to_i, :to_r, :to_s
         end
       end
     end

spec/basic_null_object_spec.rb

@@ -32,4 +32,4 @@
     expect(null_class.get.class).to be(null_class)
   end
 
-end
+end

spec/blackhole_spec.rb

@@ -13,4 +13,4 @@
     expect(null.foobaz).to be(null)
     expect(null << "bar").to be(null)
   end
-end
+end

spec/explicit_conversions_spec.rb

@@ -0,0 +1,17 @@
+require 'spec_helper.rb'
+
+describe 'explicitly convertable null object' do
+  let(:null_class) {
+    Naught.build do |b|
+      b.define_explicit_conversions
+    end
+  }
+  subject(:null) { null_class.new }
+
+  NIL_CONVERSION_METHODS.each do |conversion_method|
+    it "##{conversion_method} responds like nil" do
+      # We need to call inspect to compare Enumerators
+      expect(null.__send__(conversion_method).inspect).to eq(nil.send(conversion_method).inspect)
+    end
+  end
+end

spec/functions/actual_spec.rb

@@ -19,4 +19,4 @@
     expect(Actual{ConvertableNull.new}).to be_nil
     expect(Actual{"foo"}).to eq("foo")
   end
-end
+end

spec/functions/just_spec.rb

@@ -19,4 +19,4 @@
     expect{Just{nil}.class}.to raise_error(ArgumentError)
     expect(Just{"foo"}).to eq("foo")
   end
-end
+end

spec/functions/maybe_spec.rb

@@ -32,4 +32,4 @@
     expect(Maybe{nil}.class).to eq(ConvertableNull)
     expect(Maybe{"foo"}).to eq("foo")
   end
-end
+end

spec/functions/null_spec.rb

@@ -31,4 +31,4 @@
     expect(null.__file__).to eq(__FILE__)
   end
 
-end
+end

spec/implicit_conversions_spec.rb

@@ -22,4 +22,4 @@
     expect(null.to_str).to eq("")
   end
 
-end
+end

spec/naught/null_object_builder_spec.rb

@@ -16,10 +16,10 @@ class TestCommand
 
     it 'translates method calls into command invocations including arguments' do
       test_command = double
-      NullClassBuilder::Commands::TestCommand.should_receive(:new).
+      expect(NullClassBuilder::Commands::TestCommand).to receive(:new).
         with(builder, "foo", 42).
         and_return(test_command)
-      test_command.should_receive(:call).and_return("COMMAND RESULT")
+      expect(test_command).to receive(:call).and_return("COMMAND RESULT")
       expect(builder.test_command("foo", 42)).to eq("COMMAND RESULT")
     end
 

spec/spec_helper.rb

@@ -1,4 +1,5 @@
 GEM_ROOT = File.expand_path("../../", __FILE__)
+NIL_CONVERSION_METHODS = nil.methods.select{|method| method.to_s =~ /^to_\w+$/}
 $:.unshift File.join(GEM_ROOT, "lib")
 
 if ENV["TRAVIS"]
@@ -10,4 +11,4 @@
 end
 
 require 'naught'
-Dir[File.join(GEM_ROOT, "spec", "support", "**/*.rb")].each { |f| require f }
+Dir[File.join(GEM_ROOT, "spec", "support", "**/*.rb")].each { |f| require f }

spec/support/convertable_null.rb

@@ -1,4 +1,4 @@
 ConvertableNull = Naught.build do |b|
   b.null_equivalents << ""
   b.traceable
-end
+end