diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index e58a483..0f2a8d2 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -23,4 +23,4 @@ jobs:
     - run: SERIALIZER=marshal bundle exec rake
     - run: SERIALIZER=json bundle exec rake
     - run: SERIALIZER=yaml bundle exec rake
-    - run: SERIALIZER=plain bundle exec rake
+    - run: SERIALIZER=pure bundle exec rake
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8d239b6..437bbd8 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -9,4 +9,4 @@ test-ruby32:
     - SERIALIZER=marshal bundle exec rake
     - SERIALIZER=json bundle exec rake
     - SERIALIZER=yaml bundle exec rake
-    - SERIALIZER=plain bundle exec rake
+    - SERIALIZER=pure bundle exec rake