embeddedci 0.1.0

BenchPod pytest client for EmbeddedCI hardware-in-the-loop testing

embeddedci (BenchPod pytest library)

A pytest-friendly Python client for an EmbeddedCI BenchPod — the same device operations you do today with benchpod-cli, available straight from your tests:

• connect to a BenchPod over wifi/network or serial
• power the target on/off
• flash firmware to the target and assert ok / not ok
• emulate an I2C sensor (BMP280) and decode the bus traffic

from embeddedci import benchpod

with benchpod.BenchPod("192.168.1.213") as bp:   # or "/dev/ttyACM0", or "serial"
    bp.ping()
    bp.power_on(benchpod.INTERNAL)
    result = bp.flash(
        file="firmware.elf", target="target/stm32f1x.cfg",
        swclk=benchpod.PIN1, swdio=benchpod.PIN2, nreset=benchpod.PIN3,
        target_power=benchpod.INTERNAL,
    )
    assert result.ok
    bp.power_off(benchpod.INTERNAL)

Install

pip install embeddedci

Flashing shells out to OpenOCD, which must be on your PATH (brew install open-ocd / apt install openocd).

Named constants (no magic numbers)

Concept	Constants	Wire value
Target-power eFuse	benchpod.INTERNAL, benchpod.EXTERNAL	1, 2
LA pins (SWCLK/SWDIO/NRESET)	benchpod.PIN1 … benchpod.PIN12	1 … 12

Plain ints still work (efuse=1, swclk=1); they're validated and coerced.

Using it in pytest

Installing the package registers a pytest plugin. Point it at a pod and use the fixtures:

pytest --benchpod-connection=192.168.1.213
# or: export BENCHPOD_CONNECTION=serial

def test_firmware_flashes(benchpod):
    benchpod.power_on(benchpod.INTERNAL)
    assert benchpod.flash(
        file="firmware.elf", target="target/stm32f1x.cfg",
        swclk=benchpod.PIN1, swdio=benchpod.PIN2,
    ).ok

# benchpod_target powers the target on for the test and off at teardown:
def test_with_powered_target(benchpod_target):
    ...

Without a connection configured the fixtures skip rather than fail, so the suite stays green in CI runners without hardware.

Connection strings

Form	Transport
192.168.1.213 or host:8080	wifi/network (JSON over TCP, port 8080 default)
/dev/ttyACM0, COM3	serial (USB CDC-ACM console)
serial / usb	serial, auto-detected by USB VID 0x2E8A

Resolution order: explicit argument / --benchpod-connection → benchpod_connection ini option → BENCHPOD_CONNECTION env var.

Status of features

Feature	State
Connect (wifi + serial)	✅
Power on/off (+ scheduled delay)	✅
Flash + assert ok/not ok	✅ (pure-Python OpenOCD remote_bitbang bridge)
Emulated I2C sensor (BMP280)	✅ wifi + serial (serial via json console mode)
I2C bus decode (benchpod.i2c)	✅ START/STOP, R/W, ACK, register reads
UART capture (capture_uart)	✅ wifi + serial
Signal helpers (capture, gpio_set)	✅ minimal, TCP transport only

Emulated I2C sensor + UART capture (HIL)

The pod can pretend to be an I2C sensor (a BMP280) on two LA channels while you capture the DUT's UART — so you can flash an app, power-cycle it, and assert on its boot output with and without the sensor present:

from embeddedci import benchpod

with benchpod.BenchPod("192.168.1.213") as bp:
    bp.flash(file="app.elf", target="target/stm32f4x.cfg",
             swclk=benchpod.PIN13, swdio=benchpod.PIN14, target_power=benchpod.INTERNAL)

    # I2C is open-drain — enable the pod's pull-ups on SDA/SCL (LA1-8 only),
    # then have the pod become a BMP280 on those lines.
    bp.enable_pullup(benchpod.PIN1, benchpod.PIN2)
    bp.enable_i2c_sensor(benchpod.Sensor.BMP280, sda=benchpod.PIN1, scl=benchpod.PIN2,
                         temperature_c=22.5, pressure_pa=101000)

    # Power-cycle while capturing UART so the boot banner lands in the window.
    cap = bp.power_cycle_and_capture(rx=benchpod.PIN5, tx=benchpod.PIN6,
                                     delay=1.5, duration=6.0, until=r"APP_OK")
    assert cap.match("APP_OK")
    assert cap.match(r"chip id match=0x58|bmp280_detected=yes")

How the power-cycle works: power_cycle_and_capture powers the eFuse off, then schedules a power-on delay seconds out (a pod-side timer via target_power's delay_ms), then enters UART capture — so the scheduled power-on, and the DUT's boot output, land inside the capture window. This sidesteps the firmware's one-connection-at-a-time limit (you can't send a power-on while the UART proxy owns the link).

rx is the LA channel the pod samples (wire the DUT's TX here); tx is the channel the pod drives (DUT's RX).

Serial gets the full JSON API too. The pod's TCP API is JSON; the serial console is normally text-only. The firmware exposes a json console command that switches the console into the same JSON dispatcher (exit with {"cmd":"json_exit"}). The serial transport enters/leaves this mode automatically, so enable_i2c_sensor(...), i2c_sensor_la_decoded(...), etc. work over serial as well as wifi — no code change in your test.

Decode the I2C bus

While the pod serves the emulated sensor it also samples the SDA/SCL lines. The benchpod.i2c module turns that raw capture into decoded transactions, so you can assert what the DUT actually did on the wire — not just that it booted:

from embeddedci import benchpod
from embeddedci.benchpod import i2c

with benchpod.BenchPod("192.168.1.213") as bp:
    bp.enable_i2c_sensor(benchpod.Sensor.BMP280, sda=benchpod.PIN7, scl=benchpod.PIN8)
    bp.power_off(benchpod.INTERNAL); bp.power_on(benchpod.INTERNAL)  # DUT boots & probes

    txns = bp.i2c_sensor_la_decoded(samples=4096, sample_rate_mhz=0.5)
    print(i2c.format_transactions(txns))
    # -> S 0x76W+ 0xD0+ Sr 0x76R+ 0x58- P   (write reg 0xD0, read chip id 0x58)
    assert i2c.read_register(txns, 0x76, 0xD0) == [0x58]

The decoder handles START/repeated-START/STOP, the R/W bit, per-byte ACK/NACK, and the common "write register pointer, then read" pattern (read_register). It works on a (scl, sda) stream too (i2c.decode_samples) and ships a waveform synthesizer (i2c.synthesize) so you can build and decode traces with no hardware — see tests/test_i2c_decode.py.

Getting started: one clean HIL test

The "hello world" of EmbeddedCI HIL — flash → emulate a BMP280 → power-cycle → assert on UART — is in examples/test_bmp280.py, with a wiring table and run command at the top:

pytest examples/test_bmp280.py \
    --benchpod-connection=/dev/tty.usbserial-0001 \   # or an IP for wifi
    --benchpod-firmware=path/to/your_app.elf

It uses the plugin's benchpod, pins and firmware fixtures and the @pytest.mark.hardware marker, and skips automatically without a connection. The pin map comes from --benchpod-swclk/-swdio/-nreset/-uart-rx/-uart-tx/-i2c-sda/-i2c-scl/-efuse options (sensible defaults) so tests aren't hardcoded to your wiring. See examples/README.md for the full wiring table.

A more thorough multi-case version (present/absent + I2C-bus decode) lives in tests/examples/test_bmp280_hil.py.

Releasing (maintainers)

Releases publish to PyPI automatically via .github/workflows/publish.yml using PyPI Trusted Publishing (OIDC) — no API token or secret is stored in GitHub.

One-time setup on PyPI (or first via TestPyPI): project → Settings → Publishing → Add a pending publisher with owner embeddedci-com, repo embeddedci-python, workflow publish.yml, environment pypi.

To cut a release:

# 1. bump the version in pyproject.toml (e.g. 0.1.0 -> 0.1.1), commit it
# 2. tag and push — the tag must match the version
git tag v0.1.1
git push origin v0.1.1

The tag push builds the sdist + wheel, runs twine check, and publishes. The git tag is the source of truth for what shipped; keep it equal to the version in pyproject.toml.

Build and verify locally before tagging:

python -m pip install build twine
python -m build           # -> dist/embeddedci-*.tar.gz and *.whl
twine check dist/*