Make ActiveSupport::Configurable work with modules

[#6486 state:committed]

Signed-off-by: Santiago Pastorino <santiago@wyeworks.com>

activesupport/lib/active_support/configurable.rb

@@ -26,7 +26,7 @@ module ActiveSupport
 
     module ClassMethods
       def config
-        @_config ||= if superclass.respond_to?(:config)
+        @_config ||= if respond_to?(:superclass) && superclass.respond_to?(:config)
           superclass.config.inheritable_copy
         else
           # create a new "anonymous" class that will host the compiled reader methods

activesupport/test/configurable_test.rb

@@ -21,6 +21,12 @@ class ConfigurableActiveSupport < ActiveSupport::TestCase
     assert_equal({ :foo => :bar }, Parent.config)
   end
 
+  test "adds a configuration hash to a module as well" do
+    mixin = Module.new { include ActiveSupport::Configurable }
+    mixin.config.foo = :bar
+    assert_equal({ :foo => :bar }, mixin.config)
+  end
+
   test "configuration hash is inheritable" do
     assert_equal :bar, Child.config.foo
     assert_equal :bar, Parent.config.foo
@@ -57,4 +63,4 @@ class ConfigurableActiveSupport < ActiveSupport::TestCase
     assert_respond_to child.config, :bar
     assert_respond_to child.new.config, :bar
   end
-end
+end