Add AS::StringInquirer#respond_to? method

Consistently with #method_missing

activesupport/lib/active_support/string_inquirer.rb

@@ -10,12 +10,18 @@ module ActiveSupport
   #   Rails.env.production?
   #
   class StringInquirer < String
-    def method_missing(method_name, *arguments)
-      if method_name[-1, 1] == "?"
-        self == method_name[0..-2]
-      else
-        super
+    private
+
+      def respond_to_missing?(method_name, include_private = false)
+        method_name[-1] == '?'
+      end
+
+      def method_missing(method_name, *arguments)
+        if method_name[-1] == '?'
+          self == method_name[0..-2]
+        else
+          super
+        end
       end
-    end
   end
 end

activesupport/test/string_inquirer_test.rb

@@ -1,15 +1,23 @@
 require 'abstract_unit'
 
 class StringInquirerTest < ActiveSupport::TestCase
+  def setup
+    @string_inquirer = ActiveSupport::StringInquirer.new('production')
+  end
+
   def test_match
-    assert ActiveSupport::StringInquirer.new("production").production?
+    assert @string_inquirer.production?
   end
 
   def test_miss
-    assert !ActiveSupport::StringInquirer.new("production").development?
+    refute @string_inquirer.development?
   end
 
   def test_missing_question_mark
-    assert_raise(NoMethodError) { ActiveSupport::StringInquirer.new("production").production }
+    assert_raise(NoMethodError) { @string_inquirer.production }
+  end
+
+  def test_respond_to
+    assert_respond_to @string_inquirer, :development?
   end
 end