--- a/gtests/pk11_gtest/pk11_curve25519_unittest.cc
+++ b/gtests/pk11_gtest/pk11_curve25519_unittest.cc
@@ -35,16 +35,19 @@ class Pkcs11Curve25519Test
     ScopedSECKEYPrivateKey privKey(key);
     ASSERT_TRUE(privKey);
 
     SECItem spkiItem = {siBuffer, toUcharPtr(spki),
                         static_cast<unsigned int>(spki_len)};
 
     ScopedCERTSubjectPublicKeyInfo certSpki(
         SECKEY_DecodeDERSubjectPublicKeyInfo(&spkiItem));
+    if (!expect_success && !certSpki) {
+      return;
+    }
     ASSERT_TRUE(certSpki);
 
     ScopedSECKEYPublicKey pubKey(SECKEY_ExtractPublicKey(certSpki.get()));
     ASSERT_TRUE(pubKey);
 
     ScopedPK11SymKey symKey(PK11_PubDeriveWithKDF(
         privKey.get(), pubKey.get(), false, nullptr, nullptr, CKM_ECDH1_DERIVE,
         CKM_SHA512_HMAC, CKA_DERIVE, 0, CKD_NULL, nullptr, nullptr));