diff --git a/activesupport/test/core_ext/range_ext_test.rb b/activesupport/test/core_ext/range_ext_test.rb
index 7a620305f3..e50b6c132a 100644
--- a/activesupport/test/core_ext/range_ext_test.rb
+++ b/activesupport/test/core_ext/range_ext_test.rb
@@ -54,7 +54,7 @@ class RangeTest < Test::Unit::TestCase
   end
 
   def test_should_include_identical_exclusive_with_floats
-    assert (1.0...10.0).include?(1.0...10.0)
+    assert((1.0...10.0).include?(1.0...10.0))
   end
 
   def test_blockless_step