diff --git a/koans/about_regular_expressions.rb b/koans/about_regular_expressions.rb
index 8344911..790bea3 100644
--- a/koans/about_regular_expressions.rb
+++ b/koans/about_regular_expressions.rb
@@ -84,6 +84,8 @@ class AboutRegularExpressions < EdgeCase::Koan
   def test_shortcut_character_classes_are_negated_with_capitals
     assert_equal __, "the number is 42"[/\D+/]
     assert_equal __, "space: \t\n"[/\S+/]
+    # ... a programmer would most likely do
+    assert_equal __, "variable_1 = 42"[/[^a-zA-Z0-9_]+/]
     assert_equal __, "variable_1 = 42"[/\W+/]
   end