Comment 0 for bug 1549256

revision 1864

System setup: Vivid + Overlay PPA (i.e. same as phones/tablets)

libqt5qml5:
  Installed: 5.4.1-1ubuntu11~overlay3
libqt5core5a:
  Installed: 5.4.1+dfsg-2ubuntu11~vivid4

UbuntuTestCase provides a flick() function whose main purpose is to produce a flick event when executed on Flickable.

I noticed that this does not always happen, causing flakiness of some of the UITK tests (in my case, it's the Scrollbar/ScrollView tests I'm working on)

Here is a test case that reproduces the issue, once every 10-200 runs, depending on the configuration (I use a simple script to run it until it fails)

Please note that uncommenting the debug lines such as onMovingChanged onFlickingChanged will make it harder to reproduce the bug.

Enabling QT_LOGGING_RULES="qt.quick.mouse.debug=true" or onContentYChanged will make it even harder.

Since I already went through the effort, I'm posting here the debug log coming from the failed and successful runs:
- Typical failed run ---> http://pastebin.ubuntu.com/15186789/ Note how "flicking" never becomes true
- Typical successful run ---> http://pastebin.ubuntu.com/15186784/

Here's the code I used to reproduce the bug:

import QtQuick 2.4
import QtTest 1.0
import Ubuntu.Test 1.0
import Ubuntu.Components 1.3
import Ubuntu.Components.Styles 1.3
import QtQml.Models 2.1

Item {
    id: main
    width: units.gu(50)
    height: units.gu(100)

    SignalSpy {
        id: signalSpy
    }
    SignalSpy {
        id: anotherSignalSpy
    }

    Item {
        anchors.fill: parent
        Item {
            width: units.gu(20)
            height: units.gu(30)
            property alias flickable: freshFlickable
            Flickable {
                id: freshFlickable
                anchors.fill: parent
                contentHeight: content.height
                contentWidth: content.width
                clip: true
                //onContentYChanged: console.log(contentY)
                //onMovingChanged: console.log("MOVING", moving)
                //onFlickingChanged: console.log("FLICKING", flicking)
                Rectangle {
                    id: content
                    width: units.gu(40)
                    height: units.gu(200)
                    color: "blue"
                }
            }
        }
    }

    UbuntuTestCase {
        name: "FlickBug"
        when: windowShown

        function setupSignalSpy(spy, target, signalName) {
            spy.clear()
            //reset signalName otherwise it will look for the old signalName in the new target
            spy.signalName = ""
            spy.target = target
            spy.signalName = signalName
        }

        function test_flickUbuntuTestCase() {
            setupSignalSpy(signalSpy, freshFlickable, "movingChanged")
            flick(freshFlickable, 50, 50, -units.gu(10), -units.gu(10))
            signalSpy.wait()
            compare(signalSpy.count, 1, "No movingChanged signal after simulating a flick.")
        }
    }
}