usb_host: Add Mock device to CDC tests

examples/peripherals/usb/host/cdc/common/cdc_acm_host/test/CMakeLists.txt

@@ -1,3 +1,3 @@
-idf_component_register(SRCS "test_cdc_acm_host.c"
+idf_component_register(SRCS "test_cdc_acm_host.c" "usb_device.c"
                        INCLUDE_DIRS "."
-                       REQUIRES cdc_acm_host unity)
+                       REQUIRES cdc_acm_host tinyusb unity)

examples/peripherals/usb/host/cdc/common/cdc_acm_host/test/test_cdc_acm_host.c

@@ -373,4 +373,11 @@ TEST_CASE("USB Host CDC-ACM driver: Error handling", "[cdc_acm][ignore]")
     vTaskDelay(20);
 }
 
+/* Following test case implements dual CDC-ACM USB device that can be used as mock device for CDC-ACM Host tests */
+void run_usb_dual_cdc_device(void);
+TEST_CASE("USB_CDC_Mock_Device_App", "[cdc_acm_device][ignore]")
+{
+    run_usb_dual_cdc_device();
+}
+
 #endif

examples/peripherals/usb/host/cdc/common/cdc_acm_host/test/usb_device.c

@@ -0,0 +1,44 @@
+/*
+ * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdint.h>
+#include "sdkconfig.h"
+#include "tinyusb.h"
+#include "tusb_cdc_acm.h"
+
+static uint8_t buf[CONFIG_TINYUSB_CDC_RX_BUFSIZE + 1];
+void tinyusb_cdc_rx_callback(int itf, cdcacm_event_t *event)
+{
+    size_t rx_size = 0;
+    /* read and write back */
+    ESP_ERROR_CHECK(tinyusb_cdcacm_read(itf, buf, CONFIG_TINYUSB_CDC_RX_BUFSIZE, &rx_size));
+    tinyusb_cdcacm_write_queue(itf, buf, rx_size);
+    tinyusb_cdcacm_write_flush(itf, 0);
+}
+
+void run_usb_dual_cdc_device(void)
+{
+    const tinyusb_config_t tusb_cfg = {}; // the configuration using default values
+    ESP_ERROR_CHECK(tinyusb_driver_install(&tusb_cfg));
+
+    tinyusb_config_cdcacm_t amc_cfg = {
+        .usb_dev = TINYUSB_USBDEV_0,
+        .cdc_port = TINYUSB_CDC_ACM_0,
+        .rx_unread_buf_sz = 64,
+        .callback_rx = &tinyusb_cdc_rx_callback, // the first way to register a callback
+        .callback_rx_wanted_char = NULL,
+        .callback_line_state_changed = NULL,
+        .callback_line_coding_changed = NULL
+    };
+
+    ESP_ERROR_CHECK(tusb_cdc_acm_init(&amc_cfg));
+#if (CONFIG_TINYUSB_CDC_COUNT > 1)
+    amc_cfg.cdc_port = TINYUSB_CDC_ACM_1;
+    ESP_ERROR_CHECK(tusb_cdc_acm_init(&amc_cfg));
+#endif
+
+    printf("USB initialization DONE\n");
+}