chumicro-pytest-device

Pytest plugin that runs your tests in a CircuitPython or MicroPython runtime, on a real board or in a unix-port subprocess.

--target picks where a test runs. The default, device, intercepts collection under any functional_tests/ directory: it stages your library and test source onto the connected board via chumicro-deploy, executes the test in the device runtime, parses the result back, and passes or fails host-side pytest with the on-device outcome. device-unit puts a library's ordinary tests/ suite on the board instead, so the cross-runtime unit tests run against real firmware. unix-port runs that same suite in a MicroPython or CircuitPython unix-port subprocess, which gives you runtime-accurate results with no board plugged in. Device targets read devices.yml and follow the same workspace conventions as the rest of the ChuMicro tooling.

Part of the ChuMicro family: small, focused Python libraries for microcontrollers and laptops. Browse all workbench tools. This is a workbench tool: it runs on your laptop and drives the boards over serial.

Install

pip install chumicro-pytest-device

That brings both ChuMicro dependencies with it: chumicro-deploy (plus its pyserial / mpremote deps) and chumicro-workspace, along with msgpack and cryptography. The plugin auto-registers via the pytest11 entry point, so you don't need a pytest_plugins = [...] line in conftest.py. Native Windows isn't currently supported (the underlying chumicro-deploy raises WindowsNotSupportedError); WSL2 works.

Quick example

A functional test reads like a normal unit test. It just runs on the board:

# libraries/mylib/functional_tests/test_heartbeat.py
import time
from chumicro_timing import Heartbeat
from chumicro_timing.ticks import ticks_ms


def test_heartbeat_fires_on_real_clock() -> None:
    heartbeat = Heartbeat(period_ms=10)
    deadline = time.monotonic() + 1.0
    fires = 0
    while time.monotonic() < deadline:
        if heartbeat.poll(ticks_ms()):
            fires += 1
    assert fires > 50

The libraries/<name>/functional_tests/ layout is what triggers the routing, so put the file there and the plugin takes over from pytest. Run it on every device your devices.yml defaults name:

pytest libraries/mylib/functional_tests --runtime both

The plugin discovers the board, stages libraries/mylib/src/ plus the test, executes on-device, parses the on-device pytest result back, and reports PASS or FAIL through host-side pytest.

With no board attached, the same library's ordinary unit tests run in a unix-port interpreter instead:

pytest libraries/mylib/tests --target unix-port --runtime micropython

What's included

Plugin modules

Pytest options

Where this fits

Two ChuMicro dependencies, both installed for you. chumicro-deploy is the transport that stages tests on a board. chumicro-workspace supplies the device-orchestration primitives the collection layer dispatches to (transport build, bootstrap runner, library-source walking) and is also what writes the devices.yml this plugin reads. Auto-registers via pytest11.

Companions

Contributing

Issues, bug reports, and pull requests are welcome, and so is "I ran it on this board and here's what happened", some of the most useful feedback a hardware project can get. Development happens in the ChuMicro repository, whose contributing guide covers setup and the test workflow.

Find this library

• PyPI: chumicro-pytest-device
• Source: workbench/pytest-device

License

MIT