Fix typo with instance variable

lib/rabl-rails/renderers/base.rb

@@ -96,7 +96,7 @@ module RablRails
       # missing method.
       #
       def method_missing(name, *args, &block)
-        @context.respond_to?(name) ? @context.send(name, *args, &block) : super
+        @_context.respond_to?(name) ? @_context.send(name, *args, &block) : super
       end
 
       #

test/renderers/json_renderer_test.rb

@@ -76,6 +76,14 @@ class TestJsonRenderer < ActiveSupport::TestCase
     @template.source = { :name => [condition, proc] }
     assert_equal %q({}), render_json_output
   end
+  
+  test "node with context method call" do
+    @context.stub(:respond_to?).with(:context_method).and_return(true)
+    @context.stub(:context_method).and_return('marty')
+    proc = lambda { |object| context_method }
+    @template.source = { :name => proc }
+    assert_equal %q({"name":"marty"}), render_json_output
+  end
 
   test "partial should be evaluated at rendering time" do
     # Set assigns