Add tests for keyword arguments in Ruby 2.0

src/about_methods.rb

@@ -77,6 +77,36 @@ 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
 
   # ------------------------------------------------------------------