Measurements

Enrich each phase with one or more measurements.

Overview

A measurement is a captured value, like a voltage, temperature, or pass/fail condition. Measurements can include numeric limits, units, and outcomes. Each phase can include one or more measurements. These can be numeric, boolean, string, or multi-dimensional arrays.

Integration

With OpenHTF, you simply define the measurements using openhtf.measures and openhtf.Measurement, and TofuPilot collects the information automatically.

import openhtf as htf
from openhtf.util import units
from tofupilot.openhtf import TofuPilot


# Decorator to set measurement name, unit and limits
@htf.measures(htf.Measurement("voltage").in_range(3.1,
              3.5).with_units(units.VOLT))
# Phase returns a Pass status because measurement (3.3) is within defined
# limits [3.1, 3.5]
def phase_voltage_measure(test):
    test.measurements.voltage = 3.3


def main():
    test = htf.Test(
        phase_voltage_measure,
        procedure_id="FVT1",
        part_number="PCB1")

    with TofuPilot(test):
        test.execute(lambda: "PCB1A001")


if __name__ == "__main__":
    main()

Measurements properties

Name
measurements
Type
array (optional)
Description
List of measurements in the phase.
Name
name
Type
string
Description
Name of one measurement.
Name
outcome
Type
"PASS" | "FAIL" | "UNSET"
Description
Outcome of the measurement.
Name
measured_value
Type
number | string | boolean | dict (optional)
Description
Captured value.
Name
units
Type
string | array (optional)
Description
Units of the value. Examples: Volts, Celsius
Name
lower_limit
Type
number (optional)
Description
Minimum valid value (only for numbers).
Name
upper_limit
Type
number (optional)
Description
Maximum valid value (only for numbers).

Numerical

You can use numerical measurement to capture quantities like voltage, resistance, or temperature.

import openhtf as htf
from openhtf.util import units
from tofupilot.openhtf import TofuPilot


@htf.measures(
    htf.Measurement("temperature")  # Declares the measurement name
    .in_range(0, 100)  # Defines the lower and upper limits
    .with_units(units.DEGREE_CELSIUS)  # Specifies the unit
)
def phase_temperature(test):
    test.measurements.temperature = 25  # Set the temperature measured value to 25°C


def main():
    test = htf.Test(
        phase_temperature,
        procedure_id="FVT1",  # Create the procedure first in the Application
        part_number="PCB1",
    )

    with TofuPilot(test):
        test.execute(lambda: "PCB001")


if __name__ == "__main__":
    main()

String

Used to capture serial numbers, firmware versions, or textual responses.

import openhtf as htf
from tofupilot.openhtf import TofuPilot


@htf.measures(htf.Measurement("firmware_version").equals("1.2.4"))
def phase_firmware(test):
    test.measurements.firmware_version = "1.2.4"


def main():
    test = htf.Test(
        phase_firmware,
        procedure_id="FVT1",  # Create the procedure first in the Application
        part_number="PCB1",
    )

    with TofuPilot(test):
        test.execute(lambda: "PCB001")


if __name__ == "__main__":
    main()

Boolean

Used for pass/fail conditions, feature flags, or toggled states.

import openhtf as htf
from tofupilot.openhtf import TofuPilot


@htf.measures(htf.Measurement("is_led_switch_on").equals(True))
def phase_led(test):
    test.measurements.is_led_switch_on = True


def main():
    test = htf.Test(
        phase_led,
        procedure_id="FVT1",  # Create the procedure first in the Application
        part_number="PCB1",
    )

    with TofuPilot(test):
        test.execute(lambda: "PCB001")


if __name__ == "__main__":
    main()

Multi-dimensional

You can capture arrays or time-series data within a single measurement.

import random

import openhtf as htf
from openhtf.util import units
from tofupilot.openhtf import TofuPilot


@htf.measures(
    htf.Measurement("current_voltage_resistance_over_time")
    .with_dimensions(
        units.SECOND, units.VOLT, units.AMPERE
    )  # Input axes: time, voltage, current
    .with_units(units.OHM)  # Output unit: resistance in ohms
)
def power_phase(test):
    for t in range(100):
        timestamp = t / 100
        voltage = round(random.uniform(3.3, 3.5), 2)
        current = round(random.uniform(0.3, 0.8), 3)
        resistance = voltage / current
        test.measurements.current_voltage_resistance_over_time[
            timestamp, voltage, current
        ] = resistance


def main():
    test = htf.Test(
        power_phase,
        procedure_id="FVT1",
        part_number="PCB01",
    )

    with TofuPilot(test):
        test.execute(lambda: "PCB1A003")


if __name__ == "__main__":
    main()

You can open and explore dimension-based measurements by clicking the chart button within the Phases chart on the Run page:

Example of dimension-based measurements displayed in a chart.

Multiple measurements

You can group several related measurements—whether numerical, string, boolean, or multi-dimensional—within a single test phase.

import random

import openhtf as htf
from openhtf.util import units
from tofupilot.openhtf import TofuPilot


@htf.measures(
    htf.Measurement("is_connected").equals(True),  # Boolean measure
    htf.Measurement("firmware_version").equals("1.2.7"),  # String measure
    htf.Measurement("input_voltage").in_range(3.2, 3.4).with_units(units.VOLT),
    htf.Measurement("input_current").in_range(
        maximum=1.5).with_units(units.AMPERE),
)
def phase_multi_measurements(test):
    test.measurements.is_connected = True
    test.measurements.firmware_version = "1.2.7"

    test.measurements.input_voltage = round(random.uniform(3.29, 3.42), 2)
    test.measurements.input_current = round(random.uniform(1.0, 1.55), 3)


def main():
    test = htf.Test(
        phase_multi_measurements,
        procedure_id="FVT1",
        part_number="PCB01",
    )

    with TofuPilot(test):
        test.execute(lambda: "PCB1A004")


if __name__ == "__main__":
    main()

Multi-measurements displayed in one phase

In-app view

Run page

Each test run shows a breakdown of all phases and their associated measurements.

Phases chart showing test phase and measurements management whithin TofuPilot.

Control chart

You can view measurment trends, go to the Procedure page, click on a phase (e.g., phase_one), and select the desired measurement. The Control Chart displays limits lower_limit and upper_limit and the 6-sigma standard deviation, calculated automatically.

If measurement limits have changed over time, TofuPilot uses the most recent ones for charting.

Control Chart displaying measurements trends.

To unselect a measurement, click its name on the top bar of the page or click on Clear Filter.