Add keyword arguments (with correct answers).

src/about_keyword_arguments.rb

@@ -0,0 +1,31 @@
+require File.expand_path(File.dirname(__FILE__) + '/edgecase')
+
+class AboutMethods < EdgeCase::Koan
+
+  def method_with_keyword_arguments(one: 1, two: 'two')
+    [one, two]
+  end
+
+  def test_keyword_arguments
+    assert_equal __(Array), method_with_keyword_arguments.class
+    assert_equal __([1, 'two']), method_with_keyword_arguments
+    assert_equal __(['one', 'two']), method_with_keyword_arguments(one: 'one')
+    assert_equal __([1, 2]), method_with_keyword_arguments(two: 2)
+  end
+
+  def method_with_keywork_arguments_with_mandatory_argument(one, two: 2, three: 3)
+    [one, two, three]
+  end
+
+  def test_keyword_arguments_with_wrong_number_of_arguments
+    exception = assert_raise (___(ArgumentError)) do
+      method_with_keywork_arguments_with_mandatory_argument
+    end
+    assert_match(/#{__("wrong number of arguments")}/, exception.message)
+  end
+
+  # THINK ABOUT IT:
+  #
+  # Keyword arguments always have a default value, making them optional to the caller
+
+end

src/about_message_passing.rb

@@ -93,11 +93,11 @@ class AboutMessagePassing < EdgeCase::Koan
     # NOTE:
     #
     # In Ruby 1.8 the method_missing method is public and can be
-    # called as shown above.  However, in Ruby 1.9 the method_missing
+    # called as shown above. However, in Ruby 1.9 (and later versions)
-    # method is private.  We explicitly made it public in the testing
+    # the method_missing method is private. We explicitly made it
-    # framework so this example works in both versions of Ruby.  Just
+    # public in the testing framework so this example works in both
-    # keep in mind you can't call method_missing like that in Ruby
+    # versions of Ruby. Just keep in mind you can't call
-    # 1.9. normally.
+    # method_missing like that after Ruby 1.9 normally.
     #
     # Thanks.  We now return you to your regularly scheduled Ruby
     # Koans.

src/about_methods.rb

@@ -77,36 +77,6 @@ class AboutMethods < EdgeCase::Koan
     assert_equal __([:one]), method_with_var_args(:one)
     assert_equal __([:one, :two]), method_with_var_args(:one, :two)
   end
- # ------------------------------------------------------------------
-
-  if ruby_version?('2.0')
-    def method_with_keyword_arguments(one: 1, two: 'two')
-      [one, two]
-    end
-
-    def test_keyword_arguments
-      assert_equal __, method_with_keyword_arguments.class
-      assert_equal __, method_with_keyword_arguments
-      assert_equal __, method_with_keyword_arguments(one: 'one')
-      assert_equal __, method_with_keyword_arguments(two: 2)
-    end
-
-    def method_with_keywork_arguments_with_mandatory_argument(one, two: 2, three: 3)
-      [one, two, three]
-    end
-
-    def test_keyword_arguments_with_wrong_number_of_arguments
-      exception = assert_raise (__) do
-        method_with_keywork_arguments_with_mandatory_argument
-      end
-      assert_match(/__/, exception.message)
-    end
-
-    # THINK ABOUT IT:
-    #
-    # Keyword arguments always have a default value, making them optional to the caller
-
-  end
 
   # ------------------------------------------------------------------
 

src/edgecase.rb

@@ -65,7 +65,7 @@ class Object
     end
   end
 
-  in_ruby_version("1.9") do
+  in_ruby_version("1.9", "2") do
     public :method_missing
   end
 end

src/path_to_enlightenment.rb

@@ -12,6 +12,9 @@ require 'about_strings'
 require 'about_symbols'
 require 'about_regular_expressions'
 require 'about_methods'
+in_ruby_version("2") do
+  require 'about_keyword_arguments'
+end
 require 'about_constants'
 require 'about_control_statements'
 require 'about_true_and_false'