diff --git a/exercises/collatz-conjecture/.meta/generator/collatz_conjecture_case.rb b/exercises/collatz-conjecture/.meta/generator/collatz_conjecture_case.rb
index 0d0804c271..55333f5b7a 100644
--- a/exercises/collatz-conjecture/.meta/generator/collatz_conjecture_case.rb
+++ b/exercises/collatz-conjecture/.meta/generator/collatz_conjecture_case.rb
@@ -1,7 +1,6 @@
 require 'generator/exercise_case'
 
 class CollatzConjectureCase < Generator::ExerciseCase
-  using Generator::Underscore
 
   def workload
     case expected
@@ -25,7 +24,7 @@ def subject_of_test
   end
 
   def input
-    number.underscore
+    literal(number)
   end
 end
 
diff --git a/exercises/space-age/.meta/generator/space_age_case.rb b/exercises/space-age/.meta/generator/space_age_case.rb
index 52b0fe7d4d..6a202502eb 100644
--- a/exercises/space-age/.meta/generator/space_age_case.rb
+++ b/exercises/space-age/.meta/generator/space_age_case.rb
@@ -1,10 +1,9 @@
 require 'generator/exercise_case'
 
 class SpaceAgeCase < Generator::ExerciseCase
-  using Generator::Underscore
 
   def workload
-    indent_lines(["age = SpaceAge.new(#{seconds.underscore})",
+    indent_lines(["age = SpaceAge.new(#{literal(seconds)})",
       "assert_in_delta #{expected}, age.on_#{planet.downcase}, DELTA"
     ], 4)
   end
diff --git a/exercises/sum-of-multiples/.meta/generator/sum_of_multiples_case.rb b/exercises/sum-of-multiples/.meta/generator/sum_of_multiples_case.rb
index 23ff8a838d..b4420f0532 100644
--- a/exercises/sum-of-multiples/.meta/generator/sum_of_multiples_case.rb
+++ b/exercises/sum-of-multiples/.meta/generator/sum_of_multiples_case.rb
@@ -4,7 +4,7 @@ class SumOfMultiplesCase < Generator::ExerciseCase
   using Generator::Underscore
 
   def workload
-    assert_expected = "assert_equal #{expected.underscore}"
+    assert_expected = "assert_equal #{underscore(expected)}"
     value = "SumOfMultiples.new(#{factors.join(', ')}).to(#{limit})"
     indent_lines(["#{assert_expected}, #{value}"], 4)
   end
diff --git a/lib/generator/exercise_case.rb b/lib/generator/exercise_case.rb
index 6278494adb..774ac81e4e 100644
--- a/lib/generator/exercise_case.rb
+++ b/lib/generator/exercise_case.rb
@@ -27,5 +27,20 @@ def method_missing(sym, *args, &block)
     def respond_to?(sym, include_private = false)
       canonical.respond_to?(sym) || super
     end
+
+    protected
+
+    def literal(number)
+      number.underscore
+    end
+
+    def underscore(string)
+      string.underscore
+    end
+
+    def camel_case(string)
+      string.camel_case
+    end
+
   end
 end