automated embedded testing using python

SETUP ON UBUNTU

sudo apt install python3-venv git
python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

Add your user to the dialout group to access the serial port (sudo usermod -aG dialout $USER, then log out and back in).

ST-Link (Nucleo) udev rules

Without these, pyOCD can't open the ST-Link unless run as root.

git clone --depth 1 https://github.com/pyocd/pyOCD.git /tmp/pyocd-src
sudo cp /tmp/pyocd-src/udev/*.rules /etc/udev/rules.d/
sudo udevadm control --reload-rules && sudo udevadm trigger

Then unplug and replug the board.

J-Link

Install the SEGGER J-Link Software Pack (.deb) from https://www.segger.com/downloads/jlink/ :

sudo apt install ./JLink_Linux_*_x86_64.deb

It provides libjlinkarm.so and its own udev rules. The Python side (pylink-square) is installed with pyocd.

Check the probe is seen

pyocd list                       # shows probes and their unique IDs
pyocd list --targets             # built-in target names
pyocd pack install stm32f4       # only if your chip isn't built in

Running test

pytest or pytest --port=/dev/ttyACM0

//lets you see the test case you passed and failed pytest -v -s or pytest --port=/dev/ttyACM0 -v -s

The code currently in test_device.py need to be implemented and uploaded to your microcontroller for it to work.

Basic implementation in main.cpp

#include <Arduino.h>

void setup() { Serial.begin(115200); Serial.println("Ready"); }

void loop() { if (!Serial.available()) return;

String line = Serial.readStringUntil('\n'); line.trim();

if (line.startsWith("ADD1 ")) { Serial.println(line.substring(5).toInt() + 1); } else if (line.startsWith("Double ")) { Serial.println(line.substring(7).toInt() * 2); } else { Serial.println("ERR unknown command"); } }