Evaluate expression for assert_difference in the scope of the block

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6701 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

2 files changed, 8 insertions, 1 deletions

diff --git a/activesupport/lib/active_support/core_ext/test/difference.rb b/activesupport/lib/active_support/core_ext/test/difference.rb
index 7b22b32d26..17cac8919d 100644
--- a/activesupport/lib/active_support/core_ext/test/difference.rb
+++ b/activesupport/lib/active_support/core_ext/test/difference.rb
@@ -20,7 +20,7 @@ module Test #:nodoc:
       #     post :delete, :id => ...
       #   end
       def assert_difference(expression, difference = 1, &block)
-        expression_evaluation = lambda { eval(expression) }
+        expression_evaluation = lambda { eval(expression, block.binding) }
         original_value        = expression_evaluation.call
         yield
         assert_equal original_value + difference, expression_evaluation.call
diff --git a/activesupport/test/test_test.rb b/activesupport/test/test_test.rb
index d8a02b5497..e29534ccaf 100644
--- a/activesupport/test/test_test.rb
+++ b/activesupport/test/test_test.rb
@@ -46,4 +46,11 @@ class AssertDifferenceTest < Test::Unit::TestCase
       @object.decrement
     end
   end
+
+  def test_expression_is_evaluated_in_the_appropriate_scope
+    local_scope = 'foo'
+    assert_difference 'local_scope; @object.num' do
+      @object.increment
+    end
+  end
 end