Read and write X25519 and X448 private keys

Signed-off-by: Jethro Beekman <jethro@fortanix.com>
Co-authored-by: Gijs Kwakkel <gijs.kwakkel@fortanix.com>
Signed-off-by: Gijs Kwakkel <gijs.kwakkel@fortanix.com>
diff --git a/tests/suites/test_suite_pkwrite.data b/tests/suites/test_suite_pkwrite.data
index 34bf0da..33f1b06 100644
--- a/tests/suites/test_suite_pkwrite.data
+++ b/tests/suites/test_suite_pkwrite.data
@@ -38,6 +38,14 @@
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_ECP_DP_BP512R1_ENABLED
 pk_write_pubkey_check:"data_files/ec_bp512_pub.der":TEST_DER
 
+Public key write check EC X25519
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+pk_write_pubkey_check:"data_files/ec_x25519_pub.pem":TEST_PEM
+
+Public key write check EC X448
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_CURVE448_ENABLED
+pk_write_pubkey_check:"data_files/ec_x448_pub.pem":TEST_PEM
+
 Private key write check RSA
 depends_on:MBEDTLS_RSA_C:MBEDTLS_PEM_PARSE_C:MBEDTLS_PEM_WRITE_C
 pk_write_key_check:"data_files/server1.key":TEST_PEM
@@ -113,3 +121,11 @@
 Derive public key EC Brainpool 512 bits
 depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_ECP_DP_BP512R1_ENABLED
 pk_write_public_from_private:"data_files/ec_bp512_prv.der":"data_files/ec_bp512_pub.der"
+
+Private key write check EC X25519
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_CURVE25519_ENABLED
+pk_write_key_check:"data_files/ec_x25519_prv.pem":TEST_PEM
+
+Private key write check EC X448
+depends_on:MBEDTLS_ECP_LIGHT:MBEDTLS_BASE64_C:MBEDTLS_ECP_DP_CURVE448_ENABLED
+pk_write_key_check:"data_files/ec_x448_prv.pem":TEST_PEM