diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c
index 9d72ea1111..7b4eda3fa7 100644
--- a/src/or/circuitlist.c
+++ b/src/or/circuitlist.c
@@ -302,8 +302,8 @@ channel_note_destroy_pending(channel_t *chan, circid_t id)
 
 /** Called to indicate that a DESTROY is no longer pending on <b>chan</b> with
  * circuit ID <b>id</b> -- typically, because it has been sent. */
-void
-channel_note_destroy_not_pending(channel_t *chan, circid_t id)
+MOCK_IMPL(void, channel_note_destroy_not_pending,
+          (channel_t *chan, circid_t id))
 {
   circuit_t *circ = circuit_get_by_circid_channel_even_if_marked(id,chan);
   if (circ) {
diff --git a/src/or/circuitlist.h b/src/or/circuitlist.h
index 03934f971e..a8d746be53 100644
--- a/src/or/circuitlist.h
+++ b/src/or/circuitlist.h
@@ -72,7 +72,8 @@ void circuit_free_all(void);
 void circuits_handle_oom(size_t current_allocation);
 
 void channel_note_destroy_pending(channel_t *chan, circid_t id);
-void channel_note_destroy_not_pending(channel_t *chan, circid_t id);
+MOCK_DECL(void, channel_note_destroy_not_pending,
+          (channel_t *chan, circid_t id));
 
 #ifdef CIRCUITLIST_PRIVATE
 STATIC void circuit_free(circuit_t *circ);