diff --git a/src/crypto/x509/x509_test.cc b/src/crypto/x509/x509_test.cc
index cd4e61d..158fd45 100644
--- a/src/crypto/x509/x509_test.cc
+++ b/src/crypto/x509/x509_test.cc
@@ -26,6 +26,7 @@
 #include <openssl/pem.h>
 #include <openssl/pool.h>
 #include <openssl/x509.h>
+#include <openssl/x509v3.h>
 
 #include "../internal.h"
 
@@ -834,7 +835,7 @@
 
   /* This ensures the X509 took a reference to |buf|, otherwise this will be a
    * reference to free memory and ASAN should notice. */
-  ASSERT_EQ(0x30, enc_pointer[0]);
+  ASSERT_EQ(CBS_ASN1_SEQUENCE, enc_pointer[0]);
 }
 
 TEST(X509Test, TestFromBufferWithTrailingData) {
@@ -996,3 +997,41 @@
               std::string(reinterpret_cast<const char *>(contents), len));
   }
 }
+
+TEST(X509Test, PrettyPrintIntegers) {
+  static const char *kTests[] = {
+      // Small numbers are pretty-printed in decimal.
+      "0",
+      "-1",
+      "1",
+      "42",
+      "-42",
+      "256",
+      "-256",
+      // Large numbers are pretty-printed in hex to avoid taking quadratic time.
+      "0x0123456789",
+      "-0x0123456789",
+  };
+  for (const char *in : kTests) {
+    SCOPED_TRACE(in);
+    BIGNUM *bn = nullptr;
+    ASSERT_TRUE(BN_asc2bn(&bn, in));
+    bssl::UniquePtr<BIGNUM> free_bn(bn);
+
+    {
+      bssl::UniquePtr<ASN1_INTEGER> asn1(BN_to_ASN1_INTEGER(bn, nullptr));
+      ASSERT_TRUE(asn1);
+      bssl::UniquePtr<char> out(i2s_ASN1_INTEGER(nullptr, asn1.get()));
+      ASSERT_TRUE(out.get());
+      EXPECT_STREQ(in, out.get());
+    }
+
+    {
+      bssl::UniquePtr<ASN1_ENUMERATED> asn1(BN_to_ASN1_ENUMERATED(bn, nullptr));
+      ASSERT_TRUE(asn1);
+      bssl::UniquePtr<char> out(i2s_ASN1_ENUMERATED(nullptr, asn1.get()));
+      ASSERT_TRUE(out.get());
+      EXPECT_STREQ(in, out.get());
+    }
+  }
+}