diff --git a/exercises/phone-number/.meta/generator/phone_number_case.rb b/exercises/phone-number/.meta/generator/phone_number_case.rb
index c42599349d..5edbe99a2d 100644
--- a/exercises/phone-number/.meta/generator/phone_number_case.rb
+++ b/exercises/phone-number/.meta/generator/phone_number_case.rb
@@ -2,6 +2,16 @@
 
 class PhoneNumberCase < Generator::ExerciseCase
   def workload
-     assert_equal(expected, "PhoneNumber.clean(#{phrase.inspect})")
+    if error_expected?
+      assert_equal(nil, subject_of_test)
+    else
+      assert_equal(expected, subject_of_test)
+    end
+  end
+
+  private
+
+  def subject_of_test
+    "PhoneNumber.clean(#{phrase.inspect})"
   end
 end
diff --git a/exercises/phone-number/phone_number_test.rb b/exercises/phone-number/phone_number_test.rb
index 3167daa11b..4716d75756 100644
--- a/exercises/phone-number/phone_number_test.rb
+++ b/exercises/phone-number/phone_number_test.rb
@@ -1,7 +1,7 @@
 require 'minitest/autorun'
 require_relative 'phone_number'
 
-# Common test data version: 1.5.0 e8a5119
+# Common test data version: 1.6.0 a317aa4
 class PhoneNumberTest < Minitest::Test
   def test_cleans_the_number
     # skip