tests: ssl: Add write early data unit test

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/tests/suites/test_suite_ssl.data b/tests/suites/test_suite_ssl.data
index 69ccf26..0592a5f 100644
--- a/tests/suites/test_suite_ssl.data
+++ b/tests/suites/test_suite_ssl.data
@@ -3294,3 +3294,6 @@
 
 TLS 1.3 cli, early data status, hello retry request
 tls13_cli_early_data_status:TEST_EARLY_DATA_HRR
+
+TLS 1.3 write early data, early data accepted
+tls13_write_early_data:TEST_EARLY_DATA_ACCEPTED
diff --git a/tests/suites/test_suite_ssl.function b/tests/suites/test_suite_ssl.function
index 2751e58..840a201 100644
--- a/tests/suites/test_suite_ssl.function
+++ b/tests/suites/test_suite_ssl.function
@@ -4101,3 +4101,203 @@
     PSA_DONE();
 }
 /* END_CASE */
+
+/* BEGIN_CASE depends_on:MBEDTLS_SSL_EARLY_DATA:MBEDTLS_SSL_CLI_C:MBEDTLS_SSL_SRV_C:MBEDTLS_TEST_AT_LEAST_ONE_TLS1_3_CIPHERSUITE:MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED:MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED:MBEDTLS_MD_CAN_SHA256:MBEDTLS_ECP_HAVE_SECP256R1:MBEDTLS_ECP_HAVE_SECP384R1:MBEDTLS_PK_CAN_ECDSA_VERIFY:MBEDTLS_SSL_SESSION_TICKETS */
+void tls13_write_early_data(int scenario)
+{
+    int ret = -1;
+    mbedtls_test_ssl_endpoint client_ep, server_ep;
+    mbedtls_test_handshake_test_options client_options;
+    mbedtls_test_handshake_test_options server_options;
+    mbedtls_ssl_session saved_session;
+
+    int client_state, previous_client_state;
+    const char *early_data_string = "This is early data.";
+    const unsigned char *early_data = (const unsigned char *) early_data_string;
+    size_t early_data_len = strlen(early_data_string);
+    int write_early_data_ret;
+
+    mbedtls_platform_zeroize(&client_ep, sizeof(client_ep));
+    mbedtls_platform_zeroize(&server_ep, sizeof(server_ep));
+    mbedtls_test_init_handshake_options(&client_options);
+    mbedtls_test_init_handshake_options(&server_options);
+    mbedtls_ssl_session_init(&saved_session);
+
+    PSA_INIT();
+
+    /*
+     * Run first handshake to get a ticket from the server.
+     */
+    client_options.pk_alg = MBEDTLS_PK_ECDSA;
+    client_options.early_data = MBEDTLS_SSL_EARLY_DATA_ENABLED;
+    server_options.pk_alg = MBEDTLS_PK_ECDSA;
+    server_options.early_data = MBEDTLS_SSL_EARLY_DATA_ENABLED;
+
+    ret = mbedtls_test_get_tls13_ticket(&client_options, &server_options,
+                                        &saved_session);
+    TEST_EQUAL(ret, 0);
+
+
+    /*
+     * Prepare for handshake with the ticket.
+     */
+    switch (scenario) {
+        case TEST_EARLY_DATA_ACCEPTED:
+            break;
+
+        default:
+            TEST_FAIL("Unknown scenario.");
+    }
+
+    ret = mbedtls_test_ssl_endpoint_init(&client_ep, MBEDTLS_SSL_IS_CLIENT,
+                                         &client_options, NULL, NULL, NULL);
+    TEST_EQUAL(ret, 0);
+
+    ret = mbedtls_test_ssl_endpoint_init(&server_ep, MBEDTLS_SSL_IS_SERVER,
+                                         &server_options, NULL, NULL, NULL);
+    TEST_EQUAL(ret, 0);
+
+    mbedtls_ssl_conf_session_tickets_cb(&server_ep.conf,
+                                        mbedtls_test_ticket_write,
+                                        mbedtls_test_ticket_parse,
+                                        NULL);
+
+    ret = mbedtls_test_mock_socket_connect(&(client_ep.socket),
+                                           &(server_ep.socket), 1024);
+    TEST_EQUAL(ret, 0);
+
+    ret = mbedtls_ssl_set_session(&(client_ep.ssl), &saved_session);
+    TEST_EQUAL(ret, 0);
+
+    /*
+     * Run handshakes and test the writing of early data in each possible
+     * state.
+     */
+    previous_client_state = MBEDTLS_SSL_HELLO_REQUEST;
+    client_state = MBEDTLS_SSL_HELLO_REQUEST;
+
+    while (client_state != MBEDTLS_SSL_HANDSHAKE_OVER) {
+        TEST_EQUAL(mbedtls_test_move_handshake_to_state(
+                       &(client_ep.ssl), &(server_ep.ssl),
+                       previous_client_state), 0);
+
+        /* Progress the handshake from at least one state */
+        while (client_ep.ssl.state == previous_client_state) {
+            ret = mbedtls_ssl_handshake_step(&(client_ep.ssl));
+            TEST_ASSERT((ret == 0) ||
+                        (ret == MBEDTLS_ERR_SSL_WANT_READ) ||
+                        (ret == MBEDTLS_ERR_SSL_WANT_WRITE));
+            if (client_ep.ssl.state != previous_client_state) {
+                break;
+            }
+            ret = mbedtls_ssl_handshake_step(&(server_ep.ssl));
+            TEST_ASSERT((ret == 0) ||
+                        (ret == MBEDTLS_ERR_SSL_WANT_READ) ||
+                        (ret == MBEDTLS_ERR_SSL_WANT_WRITE));
+        }
+
+        client_state = client_ep.ssl.state;
+        write_early_data_ret = mbedtls_ssl_write_early_data(&(client_ep.ssl),
+                                                            early_data,
+                                                            early_data_len);
+
+        switch (client_state) {
+            case MBEDTLS_SSL_CLIENT_HELLO:
+                switch (scenario) {
+                    case TEST_EARLY_DATA_ACCEPTED:
+                        TEST_EQUAL(write_early_data_ret, early_data_len);
+                        TEST_EQUAL(client_ep.ssl.state, MBEDTLS_SSL_SERVER_HELLO);
+                        break;
+                }
+                break;
+
+            case MBEDTLS_SSL_SERVER_HELLO:
+                switch (scenario) {
+                    case TEST_EARLY_DATA_ACCEPTED:
+                        TEST_EQUAL(write_early_data_ret, early_data_len);
+                        TEST_EQUAL(client_ep.ssl.state, MBEDTLS_SSL_SERVER_HELLO);
+                        break;
+                }
+                break;
+
+            case MBEDTLS_SSL_ENCRYPTED_EXTENSIONS:
+                switch (scenario) {
+                    case TEST_EARLY_DATA_ACCEPTED:
+                        TEST_EQUAL(write_early_data_ret, early_data_len);
+                        TEST_EQUAL(client_ep.ssl.state, MBEDTLS_SSL_ENCRYPTED_EXTENSIONS);
+                        break;
+                }
+                break;
+
+            case MBEDTLS_SSL_SERVER_FINISHED:
+                switch (scenario) {
+                    case TEST_EARLY_DATA_ACCEPTED:
+                        TEST_EQUAL(write_early_data_ret, early_data_len);
+                        TEST_EQUAL(client_ep.ssl.state, MBEDTLS_SSL_SERVER_FINISHED);
+                        break;
+                }
+                break;
+
+            case MBEDTLS_SSL_END_OF_EARLY_DATA:
+                TEST_EQUAL(scenario, TEST_EARLY_DATA_ACCEPTED);
+                TEST_EQUAL(write_early_data_ret, MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA);
+                TEST_EQUAL(client_ep.ssl.state, MBEDTLS_SSL_END_OF_EARLY_DATA);
+                break;
+
+#if defined(MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE)
+            case MBEDTLS_SSL_CLIENT_CCS_AFTER_CLIENT_HELLO:
+                switch (scenario) {
+                    case TEST_EARLY_DATA_ACCEPTED:
+                        TEST_EQUAL(write_early_data_ret, early_data_len);
+                        TEST_EQUAL(client_ep.ssl.state, MBEDTLS_SSL_SERVER_HELLO);
+                        break;
+                }
+                break;
+
+#endif /* MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE */
+
+            case MBEDTLS_SSL_CLIENT_CERTIFICATE: /* Intentional fallthrough */
+            case MBEDTLS_SSL_CLIENT_FINISHED: /* Intentional fallthrough */
+            case MBEDTLS_SSL_FLUSH_BUFFERS: /* Intentional fallthrough */
+            case MBEDTLS_SSL_HANDSHAKE_WRAPUP: /* Intentional fallthrough */
+            case MBEDTLS_SSL_HANDSHAKE_OVER:
+                switch (scenario) {
+                    case TEST_EARLY_DATA_ACCEPTED:
+                        TEST_EQUAL(write_early_data_ret, MBEDTLS_ERR_SSL_CANNOT_WRITE_EARLY_DATA);
+                        TEST_EQUAL(client_ep.ssl.state, client_state);
+                        break;
+                }
+                break;
+
+            default:
+                TEST_FAIL("Unexpected state.");
+        }
+
+        mbedtls_test_mock_socket_close(&(client_ep.socket));
+        mbedtls_test_mock_socket_close(&(server_ep.socket));
+
+        ret = mbedtls_ssl_session_reset(&(client_ep.ssl));
+        TEST_EQUAL(ret, 0);
+
+        ret = mbedtls_ssl_set_session(&(client_ep.ssl), &saved_session);
+        TEST_EQUAL(ret, 0);
+
+        ret = mbedtls_ssl_session_reset(&(server_ep.ssl));
+        TEST_EQUAL(ret, 0);
+
+        ret = mbedtls_test_mock_socket_connect(&(client_ep.socket),
+                                               &(server_ep.socket), 1024);
+        TEST_EQUAL(ret, 0);
+
+        previous_client_state = client_state;
+    }
+
+exit:
+    mbedtls_test_ssl_endpoint_free(&client_ep, NULL);
+    mbedtls_test_ssl_endpoint_free(&server_ep, NULL);
+    mbedtls_test_free_handshake_options(&client_options);
+    mbedtls_test_free_handshake_options(&server_options);
+    mbedtls_ssl_session_free(&saved_session);
+    PSA_DONE();
+}
+/* END_CASE */