Fixed behavior of attribute_methods_generated? [#3220 state:resolved]

Signed-off-by: Joshua Peek <josh@joshpeek.com>

activemodel/lib/active_model/attribute_methods.rb

@@ -165,6 +165,7 @@ def #{matcher.method_name(attr_name)}(*args)
             end
           end
         end
+        @attribute_methods_generated = true
       end
 
       def undefine_attribute_methods
@@ -176,7 +177,6 @@ def undefine_attribute_methods
 
       def generated_attribute_methods #:nodoc:
         @generated_attribute_methods ||= begin
-          @attribute_methods_generated = true
           mod = Module.new
           include mod
           mod

activemodel/test/cases/attribute_methods_test.rb

@@ -4,6 +4,15 @@ class ModelWithAttributes
   include ActiveModel::AttributeMethods
 
   attribute_method_suffix ''
+
+  def attributes
+    { :foo => 'value of foo' }
+  end
+
+private
+  def attribute(name)
+    attributes[name.to_sym]
+  end
 end
 
 class ModelWithAttributes2
@@ -17,4 +26,21 @@ class AttributeMethodsTest < ActiveModel::TestCase
     assert_not_equal ModelWithAttributes.send(:attribute_method_matchers),
                      ModelWithAttributes2.send(:attribute_method_matchers)
   end
+
+  test '#define_attribute_methods generates attribute methods' do
+    ModelWithAttributes.define_attribute_methods([:foo])
+
+    assert ModelWithAttributes.attribute_methods_generated?
+    assert ModelWithAttributes.new.respond_to?(:foo)
+    assert_equal "value of foo", ModelWithAttributes.new.foo
+  end
+
+  test '#undefine_attribute_methods removes attribute methods' do
+    ModelWithAttributes.define_attribute_methods([:foo])
+    ModelWithAttributes.undefine_attribute_methods
+
+    assert !ModelWithAttributes.attribute_methods_generated?
+    assert !ModelWithAttributes.new.respond_to?(:foo)
+    assert_raises(NoMethodError) { ModelWithAttributes.new.foo }
+  end
 end