diff --git a/tests/pthread_test.cpp b/tests/pthread_test.cpp
index f45e2e6..797468e 100644
--- a/tests/pthread_test.cpp
+++ b/tests/pthread_test.cpp
@@ -723,7 +723,7 @@
 static void AtForkChild2() { g_atfork_child_calls = (g_atfork_child_calls << 4) | 2; }
 
 TEST(pthread, pthread_atfork_smoke) {
-  test_forked([]() {
+  test_isolated([] {
     ASSERT_EQ(0, pthread_atfork(AtForkPrepare1, AtForkParent1, AtForkChild1));
     ASSERT_EQ(0, pthread_atfork(AtForkPrepare2, AtForkParent2, AtForkChild2));