mouseDrag positionChanged incorrect

import QtQuick 2.14
import QtTest 1.14

MouseArea {
    id: root
    width: 200
    height: 200

    signal mouseDragSignal(string signalName, int mouse_x)

    onPressed: {
        root.mouseDragSignal("pressed", mouse.x)
    }

    onPositionChanged: {
        root.mouseDragSignal("positionChanged", mouse.x)
    }

    onReleased: {
        root.mouseDragSignal("released", mouse.x)
    }


    SignalSpy {
        id: mouseDragSignalSpy
        target: root
        signalName: "mouseDragSignal"
    }

    TestCase {
        id: testCase
        name: "MouseDragTests"
        when: windowShown

        function test_affect_of_mouseDrag_on_positionChanged() {
            let start = 1
            let dragDist = 1
            mouseDrag(root, start, start, dragDist, dragDist)
            let mouseStayedBetweenStartAndEndPt = true
            for (let i = 0; i < mouseDragSignalSpy.signalArguments.length; i++) {
                let signalName = mouseDragSignalSpy.signalArguments[i][0]
                let mouse_x = mouseDragSignalSpy.signalArguments[i][1]

                print("signalName: " + signalName + " mouse_x: " + mouse_x)
                if(mouse_x < start || mouse_x > start + dragDist)
                    mouseStayedBetweenStartAndEndPt = false
            }
            verify(mouseStayedBetweenStartAndEndPt)
        }

    }
}

QDEBUG : MouseDragTests::test_affect_of_mouseDrag_on_positionChanged() qml: signalName: pressed mouse_x: 1
QDEBUG : MouseDragTests::test_affect_of_mouseDrag_on_positionChanged() qml: signalName: positionChanged mouse_x: 12
QDEBUG : MouseDragTests::test_affect_of_mouseDrag_on_positionChanged() qml: signalName: positionChanged mouse_x: 3
QDEBUG : MouseDragTests::test_affect_of_mouseDrag_on_positionChanged() qml: signalName: released mouse_x: 3
FAIL!  : MouseDragTests::test_affect_of_mouseDrag_on_positionChanged() 'verify()' returned FALSE. ()