diff --git a/src/test-array.cc b/src/test-array.cc
index 6c888138e..0acf73b61 100644
--- a/src/test-array.cc
+++ b/src/test-array.cc
@@ -70,6 +70,8 @@ test_reverse_invalid ()
 int
 main (int argc, char **argv)
 {
+  assert (sizeof (hb_array_t<int>) == sizeof (hb_sorted_array_t<int>));
+
   test_reverse ();
   test_reverse_range ();
   test_reverse_invalid ();
diff --git a/src/test-vector.cc b/src/test-vector.cc
index 37bec309d..0a0ce40a2 100644
--- a/src/test-vector.cc
+++ b/src/test-vector.cc
@@ -32,6 +32,7 @@
 int
 main (int argc, char **argv)
 {
+  assert (sizeof (hb_vector_t<int>) == sizeof (hb_sorted_vector_t<int>));
 
   /* Test copy constructor. */
   {