fix(modem): Examples: use local configs for MQTT topic/data

To avoid issues in CI, as we're using public server
and could receive data by people playing with the example

Author: david-cermak

components/esp_modem/examples/simple_cmux_client/main/Kconfig.projbuild

@@ -129,4 +129,16 @@ menu "Example Configuration"
         help
             URL of an mqtt broker which this example connects to.
 
+    config EXAMPLE_MQTT_TEST_TOPIC
+        string "MQTT topic to publish/subscribe"
+        default "/topic/esp-pppos"
+        help
+            MQTT topic, which we subscribe on and publish to.
+
+    config EXAMPLE_MQTT_TEST_DATA
+        string "MQTT data to publish/receive"
+        default "esp32-pppos"
+        help
+            MQTT data message, which we publish and expect to receive.
+
 endmenu

components/esp_modem/examples/simple_cmux_client/main/simple_cmux_client_main.cpp

@@ -234,8 +234,8 @@ extern "C" void app_main(void)
         }
         std::cout << "Connected" << std::endl;
 
-        mqtt.subscribe("/topic/esp-modem");
-        mqtt.publish("/topic/esp-modem", "Hello modem");
+        mqtt.subscribe(CONFIG_EXAMPLE_MQTT_TEST_TOPIC);
+        mqtt.publish(CONFIG_EXAMPLE_MQTT_TEST_TOPIC, CONFIG_EXAMPLE_MQTT_TEST_DATA);
         if (!handler.wait_for(StatusHandler::MQTT_Data, 60000)) {
             ESP_LOGE(TAG, "Didn't receive published data within specified timeout... exiting");
             return;

components/esp_modem/examples/simple_cmux_client/pytest_cmux.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2023 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2023-2024 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Unlicense OR CC0-1.0
 from __future__ import print_function, unicode_literals
 
@@ -10,8 +10,17 @@ def test_cmux_connection(dut):
       2. checks we get an IP
       3. checks for the MQTT events
     """
+    # Get topic and data from Kconfig
+    topic = ''
+    data = ''
+    try:
+        topic = dut.app.sdkconfig.get('EXAMPLE_MQTT_TEST_TOPIC')
+        data = dut.app.sdkconfig.get('EXAMPLE_MQTT_TEST_DATA')
+    except Exception:
+        print('ENV_TEST_FAILURE: Cannot find broker url in sdkconfig')
+        raise
     # Check the sequence of connecting, publishing, disconnecting
     dut.expect('Modem has correctly entered multiplexed')
     # Check for MQTT connection and the data event
-    dut.expect('TOPIC: /topic/esp-modem')
-    dut.expect('DATA: Hello modem')
+    dut.expect(f'TOPIC: {topic}')
+    dut.expect(f'DATA: {data}')

components/esp_modem/examples/simple_cmux_client/sdkconfig.ci.sim800_cmux

@@ -15,3 +15,4 @@ CONFIG_ESP32_PANIC_PRINT_HALT=y
 CONFIG_COMPILER_CXX_EXCEPTIONS=y
 CONFIG_ESP_MAIN_TASK_STACK_SIZE=8192
 CONFIG_EXAMPLE_CLOSE_CMUX_AT_END=y
+CONFIG_EXAMPLE_MQTT_TEST_TOPIC="/ci/esp-modem/pppos-client"