diff --git a/test/gtest/helpers.cpp b/test/gtest/helpers.cpp
index 199e3a374a3..5270d04e02a 100644
--- a/test/gtest/helpers.cpp
+++ b/test/gtest/helpers.cpp
@@ -154,7 +154,7 @@ namespace Test {
     const std::string &source,
     CompilerOptions::FrontendVersion langVersion
     /* = CompilerOptions::FrontendVersion::P4_16 */,
-    P4::ParseAnnotations parseAnnotations
+    const P4::ParseAnnotations &parseAnnotations
     /* = P4::ParseAnnotations() */) {
     auto *program = P4::parseP4String(source, langVersion);
     if (program == nullptr) {
diff --git a/test/gtest/helpers.h b/test/gtest/helpers.h
index debf2193936..a3efa4b0a0c 100644
--- a/test/gtest/helpers.h
+++ b/test/gtest/helpers.h
@@ -116,10 +116,10 @@ struct FrontendTestCase {
     /// Create a test case that only requires the frontend to run.
     static std::optional<FrontendTestCase> create(
         const std::string &source, CompilerOptions::FrontendVersion langVersion = defaultVersion,
-        P4::ParseAnnotations parseAnnotations = P4::ParseAnnotations());
+        const P4::ParseAnnotations &parseAnnotations = P4::ParseAnnotations());
 
     static std::optional<FrontendTestCase> create(const std::string &source,
-                                                  P4::ParseAnnotations parseAnnotations) {
+                                                  const P4::ParseAnnotations &parseAnnotations) {
         return create(source, defaultVersion, parseAnnotations);
     }