1 files changed, 7 insertions, 1 deletions
diff --git a/railties/lib/rails/generators/testing/assertions.rb b/railties/lib/rails/generators/testing/assertions.rb
index 1cabf4e28c..c4cff9090b 100644
--- a/railties/lib/rails/generators/testing/assertions.rb
+++ b/railties/lib/rails/generators/testing/assertions.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Rails
   module Generators
     module Testing
@@ -113,7 +115,11 @@ module Rails
         #
         #   assert_field_default_value :string, "MyString"
         def assert_field_default_value(attribute_type, value)
-          assert_equal(value, create_generated_attribute(attribute_type).default)
+          if value.nil?
+            assert_nil(create_generated_attribute(attribute_type).default)
+          else
+            assert_equal(value, create_generated_attribute(attribute_type).default)
+          end
         end
       end
     end