diff --git a/test/cctest/test-bignum.cc b/test/cctest/test-bignum.cc
index 0dc9469..4f0c592 100644
--- a/test/cctest/test-bignum.cc
+++ b/test/cctest/test-bignum.cc
@@ -993,6 +993,7 @@
   other.AssignUInt16(2);
   other.ShiftLeft(500);
   CHECK_EQ(5, bignum.DivideModuloIntBignum(other));
+  CHECK(bignum.ToHexString(buffer, kBufferSize));
   CHECK_EQ("0", buffer);
 
   bignum.AssignUInt16(11);