diff --git a/src/systemcmds/tests/test_bson.c b/src/systemcmds/tests/test_bson.c
index 57cb016b99..fd17025670 100644
--- a/src/systemcmds/tests/test_bson.c
+++ b/src/systemcmds/tests/test_bson.c
@@ -233,7 +233,7 @@ decode_callback(bson_decoder_t decoder, void *private, bson_node_t node)
 			return 1;
 		}
 
-		if (memcmp(sample_data, dbuf, len)) {
+		if (memcmp(sample_data, dbuf, len) != 0) {
 			PX4_ERR("FAIL: decoder: data1 compare fail");
 			return 1;
 		}