SignalSpy QML Type▲
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Import Statement: import QtTest
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Inherits:: Item
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Group: SignalSpy is part of qtquicktest
Detailed Description▲
In the following example, a SignalSpy is installed to watch the "clicked" signal on a user-defined Button type. When the signal is emitted, the count property on the spy will be increased.
Button {
id: button
SignalSpy {
id: spy
target: button
signalName: "clicked"
}
TestCase {
name: "ButtonClick"
function test_click() {
compare(spy.count, 0)
button.clicked();
compare(spy.count, 1)
}
}
}The above style of test is suitable for signals that are emitted synchronously. For asynchronous signals, the wait() method can be used to block the test until the signal occurs (or a timeout expires).
See Also▲
See also TestCase, Qt Quick Test
Property Documentation▲
[read-only] count : int▲
This property defines the number of times that signalName has been emitted from target since the last call to clear().
See Also▲
See also target, signalName, clear()
[read-only] signalArguments : list▲
This property holds a list of emitted signal arguments. Each emission of the signal will append one item to the list, containing the arguments of the signal. When connecting to a new target or new signalName or calling the clear() method, the signalArguments will be reset to empty.
See Also▲
See also signalName, clear()
signalName : string▲
target : var▲
This property defines the target object that will be used to listen for emissions of the signalName signal.
See Also▲
See also signalName, count
[read-only] valid : bool▲
This property defines the current signal connection status. It will be true when the signalName of the target is connected successfully, otherwise it will be false.
See Also▲
See also count, target, signalName, clear()
Method Documentation▲
clear()▲
Clears count to 0, resets valid to false and clears the signalArguments to empty.
See Also▲
wait(timeout = 5000)▲
Waits for the signal signalName on target to be emitted, for up to timeout milliseconds. The test case will fail if the signal is not emitted.
SignalSpy {
id: spy
target: button
signalName: "clicked"
}
function test_async_click() {
...
// do something that will cause clicked() to be emitted
...
spy.wait()
compare(spy.count, 1)
}There are two possible scenarios: the signal has already been emitted when wait() is called, or the signal has not yet been emitted. The wait() function handles the first scenario by immediately returning if the signal has already occurred.
The clear() method can be used to discard information about signals that have already occurred to synchronize wait() with future signal emissions.
See Also▲
See also clear(), TestCase::tryCompare()