diff --git a/BUILD.gn b/BUILD.gn
index e416913..cb7e1ac 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -520,6 +520,8 @@
 }
 
 executable("asio_unittests") {
+  testonly = true
+
   sources = [
     "asio/src/tests/unit/archetypes/async_ops.hpp",
     "asio/src/tests/unit/archetypes/async_result.hpp",