diff --git a/tests/read_interface.h b/tests/read_interface.h
index 2cd826ab0..278e03742 100644
--- a/tests/read_interface.h
+++ b/tests/read_interface.h
@@ -1,3 +1,6 @@
+#ifndef PODIO_TESTS_READ_INTERFACE_H // NOLINT(llvm-header-guard): folder structure not suitable
+#define PODIO_TESTS_READ_INTERFACE_H // NOLINT(llvm-header-guard): folder structure not suitable
+
 #include "read_frame.h"
 
 #include "podio/Reader.h"
@@ -80,3 +83,5 @@ int read_frames(podio::Reader& reader) {
 
   return 0;
 }
+
+#endif // PODIO_TESTS_READ_INTERFACE_H
diff --git a/tests/write_interface.h b/tests/write_interface.h
index b6baf21ea..1acaa2383 100644
--- a/tests/write_interface.h
+++ b/tests/write_interface.h
@@ -1,3 +1,6 @@
+#ifndef PODIO_TESTS_WRITE_INTERFACE_H // NOLINT(llvm-header-guard): folder structure not suitable
+#define PODIO_TESTS_WRITE_INTERFACE_H // NOLINT(llvm-header-guard): folder structure not suitable
+
 #include "write_frame.h"
 
 #include "podio/Writer.h"
@@ -14,3 +17,5 @@ void write_frames(podio::Writer& frameWriter) {
     frameWriter.writeFrame(frame, "other_events");
   }
 }
+
+#endif // PODIO_TESTS_WRITE_INTERFACE_H