diff --git a/test/ringbuffer-test-utils.c b/test/ringbuffer-test-utils.c
index 9172648..56e37ee 100644
--- a/test/ringbuffer-test-utils.c
+++ b/test/ringbuffer-test-utils.c
@@ -5,7 +5,7 @@
 	bool force_only;
 	int count;
 	uint8_t *data;
-	int len;
+	size_t len;
 };
 
 void ringbuffer_test_context_init(struct rb_test_ctx *ctx)