DurationConstraint Item¶

class DurationConstraint¶: Checks the time between two signal occurrences.

Inherits:	`Component`
Properties:	`beginOn`, `duration`, `enabled` `endOn`, `evaluateOnFinished`, `evaluateOnValidation`, `maxDuration`, `minDuration`. `timedOut`, `valid`
Methods:	`begin()`, `end()`

Detailed Description¶

DurationConstraint measures the time between two signals beginOn and endOn. The methods begin() or end() may be used as an alternative if no signals are available. The expected duration is configured with minDuration and maxDuration.

The constraint has two stages: validation and evaluation. Validation happens immediately after the endOn signal has fired. In the same moment, the duration property is updated and shows the measured duration. Whether the duration is within the expected range, can be seen at the property valid.

During the evaluation stage, it is decided whether the test case is aborted. Evaluation can either happen immediately after validation (evaluateOnValidation is true) or just before the Testcase::finished() event (evaluateOnFinished is true). The enabled property switches measurement completely on and off.

Example for measuring the duration between two signals:

import qst 1.0

Testcase {

    ProcessProbe {
        id: process
        command: "sleep"
        arguments: [ 3 ]
    }

    DurationConstraint {
        id: constraint
        minDuration: 2.9
        maxDuration: 3.1

        beginOn: process.started
        endOn: process.finished
    }

    function run() {
        process.start()
        Qst.wait(4000)
    }

Example for monitoring a sequence of actions:

import qst 1.0

Testcase {

    DurationConstraint {
        id: constraint
        minDuration: 5
        maxDuration: 10
    }

    function run() {
        constraint.begin()

        // Now do something very time consuming...
        Qst.wait(20); // will be aborted because constraint
                      // is violated after 10 ms.
    }

Properties¶

signal beginOn¶

Default:	undefined

Starts a measurement action. This property must either be QML signal or an object that defines a connect() method with a signal handler as parameter. When updating this property, the old signal will be disconnected.

Methods¶

void begin()¶

Equivalent to beginOn. Can be used to start a measurement manually or when no signal is available to attach to.