diff --git a/tests/subsys/logging/log_api/src/mock_backend.c b/tests/subsys/logging/log_api/src/mock_backend.c
index e9cd66978ac..ab4d901c369 100644
--- a/tests/subsys/logging/log_api/src/mock_backend.c
+++ b/tests/subsys/logging/log_api/src/mock_backend.c
@@ -140,7 +140,7 @@ static void process(const struct log_backend *const backend,
 	}
 
 	zassert_equal(msg->log.hdr.timestamp, exp->timestamp,
-#if CONFIG_LOG_TIMESTAMP_64BIT
+#ifdef CONFIG_LOG_TIMESTAMP_64BIT
 		      "Got: %llu, expected: %llu",
 #else
 		      "Got: %u, expected: %u",