test/usbus_cdc_acm_stdio: USB CDC ACM STDIO test

tests/usbus_cdc_acm_stdio/Makefile

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+BOARD ?= samr21-xpro
+include ../Makefile.tests_common
+
+USEMODULE += auto_init_usbus
+USEMODULE += stdio_cdc_acm
+USEMODULE += shell
+USEMODULE += shell_commands
+USEMODULE += ps
+
+# USB device vendor and product ID
+DEFAULT_VID = 1209
+DEFAULT_PID = 0001
+USB_VID ?= $(DEFAULT_VID)
+USB_PID ?= $(DEFAULT_PID)
+
+CFLAGS += -DUSB_CONFIG_VID=0x$(USB_VID) -DUSB_CONFIG_PID=0x$(USB_PID)
+
+include $(RIOTBASE)/Makefile.include
+
+.PHONY: usb_id_check
+usb_id_check:
+	@if [ $(USB_VID) = $(DEFAULT_VID) ] || [ $(USB_PID) = $(DEFAULT_PID) ] ; then \
+		$(COLOR_ECHO) "$(COLOR_RED)Private testing pid.codes USB VID/PID used!, do not use it outside of test environments!$(COLOR_RESET)" 1>&2 ; \
+		$(COLOR_ECHO) "$(COLOR_RED)MUST NOT be used on any device redistributed, sold or manufactured, VID/PID is not unique!$(COLOR_RESET)" 1>&2 ; \
+	fi
+
+all: | usb_id_check

tests/usbus_cdc_acm_stdio/README.md

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+Expected result
+===============
+
+A second USB serial console (ttyACMx) appears when plugging the USB peripheral
+into a host computer. When opening the serial device it should show the RIOT
+shell. Basic command interaction must work.
+
+The test should work on Linux, MacOS and Windows. Putty is known to work on
+Windows.
+
+Changing the baud rate, bit mode and parity mode is accepted by the device and
+reflected back. However, changing these should not affect shell operation.
+
+Note that when testing with this firmware, the regular USB serial console from
+the attached debugger is not functional.
+
+Background
+==========
+
+This test application can be used to verify the USBUS CDC ACM implementation.
+Assuming drivers available, the board under test should show up on the host
+computer as an USB CDC Abstract Control Management device (ttyACMx on Linux).
+Drivers are available for Linux, macOS and Windows.

tests/usbus_cdc_acm_stdio/main.c

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+/*
+ * Copyright (C) 2019 Koen Zandberg <koen@bergzand.net>
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @file
+ * @brief       Basic test for USB CDC ACM functionality. When plugged into a
+ *              USB port, the peripheral should show up as a serial modem USB
+ *              peripheral (/dev/ttyACMx on Linux) and should present the RIOT
+ *              shell over this serial device.
+ *
+ * @author      Koen Zandberg <koen@bergzand.net>
+ *
+ */
+
+#include <stdio.h>
+
+#include "shell.h"
+#include "shell_commands.h"
+
+int main(void)
+{
+    (void) puts("RIOT USB CDC ACM shell test");
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
+
+    return 0;
+}