actually use them

ca/certificate-authority_test.go

@@ -356,7 +356,7 @@ func TestRevoke(t *testing.T) {
 	}
 	cert, err := x509.ParseCertificate(certObj.DER)
 	test.AssertNotError(t, err, "Certificate failed to parse")
-	serialString := fmt.Sprintf("%032x", cert.SerialNumber)
+	serialString := core.SerialToString(cert.SerialNumber)
 	err = ca.RevokeCertificate(serialString)
 	test.AssertNotError(t, err, "Revocation failed")
 
@@ -415,7 +415,7 @@ func TestIssueCertificate(t *testing.T) {
 		}
 
 		// Verify that the cert got stored in the DB
-		serialString := fmt.Sprintf("%032x", cert.SerialNumber)
+		serialString := core.SerialToString(cert.SerialNumber)
 		certBytes, err := storageAuthority.GetCertificate(serialString)
 		test.AssertNotError(t, err,
 			fmt.Sprintf("Certificate %s not found in database", serialString))

ra/registration-authority_test.go

@@ -240,7 +240,7 @@ func TestNewCertificate(t *testing.T) {
 	test.AssertNotError(t, err, "Failed to parse certificate")
 
 	// Verify that cert shows up and is as expected
-	dbCert, err := sa.GetCertificate(fmt.Sprintf("%032x", parsedCert.SerialNumber))
+	dbCert, err := sa.GetCertificate(core.SerialToString(parsedCert.SerialNumber))
 	test.AssertNotError(t, err, fmt.Sprintf("Could not fetch certificate %032x from database",
 		parsedCert.SerialNumber))
 	test.Assert(t, bytes.Compare(cert.DER, dbCert) == 0, "Certificates differ")

sa/storage-authority.go

@@ -520,7 +520,7 @@ func (ssa *SQLStorageAuthority) AddCertificate(certDER []byte) (digest string, e
 	if err != nil {
 		return
 	}
-	serial := fmt.Sprintf("%032x", parsedCertificate.SerialNumber)
+	serial := core.SerialToString(parsedCertificate.SerialNumber)
 
 	tx, err := ssa.db.Begin()
 	if err != nil {