diff --git a/test-bn.scm b/test-bn.scm
index c32c1fc9..f1945117 100644
--- a/test-bn.scm
+++ b/test-bn.scm
@@ -7,6 +7,16 @@
      bignum2string(data, k, bn, obj_obj2int(radix));
      ")
 
+ (define-c test-larger-bn
+   "(void *data, int argc, closure _, object k, object fx, object fx2, object radix)"
+   " bignum2_type *bn = gc_alloc_bignum2(data, 2);
+     C_bignum_digits(bn)[0] = obj_obj2int(fx2);
+     C_bignum_digits(bn)[1] = obj_obj2int(fx);
+     bn->num_digits = 2;
+     bn->sign = 0;
+     bignum2string(data, k, bn, obj_obj2int(radix));
+     ")
+
 (write
   (list
     (test-bn -10 10)
@@ -16,6 +26,9 @@
     (test-bn #x0FFFffff 10)
     (test-bn #x0FFFffff 16)
     (test-bn #x3FFFffff 10)
+    (test-bn #x0FFF0001 10)
+    (test-larger-bn 0 #x0FFF0001 10)
+    (test-larger-bn #x3FFF0000 #x0FFF0001 10)
   ))
 (newline)
  ;(repl)