diff --git a/bin/generate-spec b/bin/generate-spec
index 04068cf..c0dc900 100755
--- a/bin/generate-spec
+++ b/bin/generate-spec
@@ -150,10 +150,10 @@ if spec_generator.bonus
 
 
   -- The next tests are optional.
-  -- Set the environment variable ENABLE_OPTIONAL_TESTS to run them:
-  -- For example, in bash run:  ENABLE_OPTIONAL_TESTS=true busted
+  -- Set the environment variable BONUS_TESTS to run them:
+  -- For example, in bash run:  BONUS_TESTS=true busted
 
-  if os.getenv('ENABLE_OPTIONAL_TESTS') == 'true'
+  if os.getenv('BONUS_TESTS') == 'true'
     describe 'Bonus tests', ->
 ]]
   spec ..= spec_generator.bonus
diff --git a/exercises/practice/custom-set/custom_set_spec.moon b/exercises/practice/custom-set/custom_set_spec.moon
index c288f1f..568db24 100644
--- a/exercises/practice/custom-set/custom_set_spec.moon
+++ b/exercises/practice/custom-set/custom_set_spec.moon
@@ -237,10 +237,10 @@ describe 'custom-set', ->
       assert.is.true result\is_equal expected
 
   -- The next tests are optional.
-  -- Set the environment variable ENABLE_OPTIONAL_TESTS to run them:
-  -- For example, in bash run:  ENABLE_OPTIONAL_TESTS=true busted
+  -- Set the environment variable BONUS_TESTS to run them:
+  -- For example, in bash run:  BONUS_TESTS=true busted
 
-  if os.getenv('ENABLE_OPTIONAL_TESTS') == 'true'
+  if os.getenv('BONUS_TESTS') == 'true'
     describe 'Bonus tests', ->
       pending 'use the equal operator, are equal', ->
         set1 = CustomSet {1, 2, 3, 4}
diff --git a/exercises/practice/robot-name/robot_name_spec.moon b/exercises/practice/robot-name/robot_name_spec.moon
index 4f0126a..df686f2 100644
--- a/exercises/practice/robot-name/robot_name_spec.moon
+++ b/exercises/practice/robot-name/robot_name_spec.moon
@@ -56,12 +56,12 @@ describe 'robot-name', ->
       assert.is.equal sample_size, table_size seen
 
 
-    -- The next test is optional.
-    -- Set the environment variable ENABLE_OPTIONAL_TESTS to run it:
-    -- For example, in bash run:  ENABLE_OPTIONAL_TESTS=true busted
+    -- The next tests are optional.
+    -- Set the environment variable BONUS_TESTS to run it:
+    -- For example, in bash run:  BONUS_TESTS=true busted
     -- Check the performance tip in the hints.
 
-    if os.getenv('ENABLE_OPTIONAL_TESTS') == 'true'
+    if os.getenv('BONUS_TESTS') == 'true'
       pending 'all the robots and more', ->
         Robot\reset_names!
         sample_size = 26 * 26 * 1000