per_get_undo()
diff --git a/skeletons/per_decoder.c b/skeletons/per_decoder.c
index 2e460da..4e120a4 100644
--- a/skeletons/per_decoder.c
+++ b/skeletons/per_decoder.c
@@ -47,6 +47,7 @@
 		/* Return the number of consumed bits */
 		rval.consumed = ((pd.buffer - (const uint8_t *)buffer) << 3)
 					+ pd.nboff - skip_bits;
+		assert(rval.consumed == pd.moved);
 	} else {
 		/* PER codec is not a restartable */
 		rval.consumed = 0;