diff --git a/compiler/cpp/test/plugin/conversion_test.cc b/compiler/cpp/test/plugin/conversion_test.cc
index 5159ba4..e73aa16 100644
--- a/compiler/cpp/test/plugin/conversion_test.cc
+++ b/compiler/cpp/test/plugin/conversion_test.cc
@@ -234,6 +234,8 @@
 template <typename T>
 T* round_trip(T* t) {
   typename plugin::ToType<T>::type p;
+  plugin::clear_global_cache();
+  plugin_output::clear_global_cache();
   plugin_output::convert(t, p);
   migrate_global_cache();
   return plugin::convert(p);