diff --git a/library/pk_internal.h b/library/pk_internal.h
index 416ef23..9892de6 100644
--- a/library/pk_internal.h
+++ b/library/pk_internal.h
@@ -117,5 +117,14 @@
 #endif /* MBEDTLS_ECP_DP_CURVE25519_ENABLED || MBEDTLS_ECP_DP_CURVE448_ENABLED */
 #endif /* MBEDTLS_PK_HAVE_ECC_KEYS */
 
+#if defined(MBEDTLS_TEST_HOOKS)
+
+MBEDTLS_STATIC_TESTABLE int mbedtls_pk_parse_key_pkcs8_encrypted_der(
+    mbedtls_pk_context *pk,
+    unsigned char *key, size_t keylen,
+    const unsigned char *pwd, size_t pwdlen,
+    int (*f_rng)(void *, unsigned char *, size_t), void *p_rng);
+
+#endif
 
 #endif /* MBEDTLS_PK_INTERNAL_H */