Embedded firmware test using pytest

conftest.py

import pytest
import re
import serial
from time import time

# Used to flash binary to nrf52840dk
from pynrfjprog import LowLevel

@pytest.fixture(scope='session')
def anyio_backend():
    return 'trio'

def pytest_addoption(parser):
    parser.addoption("--port",
            help="The port to which the device is attached (eg: /dev/ttyACM0)")
    parser.addoption("--baud", type=int, default=115200,
            help="Serial port baud rate (default: 115200)")
    parser.addoption("--fw-image", type=str,
            help="Firmware binary to program to device")
    parser.addoption("--serial-number", type=str,
            help="Serial number to identify on-board debugger")

@pytest.fixture(scope="session")
def port(request):
    return request.config.getoption("--port")

@pytest.fixture(scope="session")
def baud(request):
    return request.config.getoption("--baud")

@pytest.fixture(scope="session")
def fw_image(request):
    return request.config.getoption("--fw-image")

@pytest.fixture(scope="session")
def serial_number(request):
    return request.config.getoption("--serial-number")

class Board():
    def __init__(self, port, baud, fw_image, serial_number):
        self.port = port
        self.baud = baud
        self.fw_image = fw_image
        self.serial_number = serial_number

        #program firmware
        self.program(fw_image)

        self.serial_device = serial.Serial(port, self.baud, timeout=1, write_timeout=1)

    def program(self, fw_image):
        with LowLevel.API() as api:
            api.connect_to_emu_with_snr(int(self.serial_number))
            api.erase_all()
            api.program_file(self.fw_image)
            api.sys_reset()
            api.go()
            api.close()

    def wait_for_regex_in_line(self, regex, timeout_s=20, log=True):
        start_time = time()
        while True:
            self.serial_device.timeout=timeout_s
            line = self.serial_device.read_until().decode('utf-8', errors='replace').replace("\r\n", "")
            if line != "" and log:
                print(line)
            if time() - start_time > timeout_s:
                raise RuntimeError('Timeout')
            regex_search = re.search(regex, line)
            if regex_search:
                return regex_search

@pytest.fixture(scope="session")
def board(port, baud, fw_image, serial_number):
    return Board(port, baud, fw_image, serial_number)

test_hello_world.py

import pytest

pytestmark = pytest.mark.anyio

async def test_hello(board):
    assert None != board.wait_for_regex_in_line("Hello World");