signalspy.py

"""
A QSignalSpy like object, which is sadly missing from PyQt4 (but is exposed in PyQt5)

No guaranties it behaves as the real thing under all circumstances.
"""

from PyQt4.QtCore import QObject, QEventLoop, QTimer

class QSignalSpy(QObject):
    """
    QSignalSpy-like object
    """
    def __init__(self, boundsig):
        self.__boundsig = boundsig  # type: pyqtBoundSignal
        self.__boundsig.connect(lambda *args: self.__record(*args))
        self.__recorded = []  # List[List[Any]]
        self.__loop = QEventLoop()
        self.__timer = QTimer(singleShot=True)
        self.__timer.timeout.connect(self.__loop.quit)

    def __record(self, *args):
        self.__recorded.append(list(args))
        if self.__loop.isRunning():
            self.__loop.quit()

    def wait(self, timeout):
        count = len(self)
        self.__timer.stop()
        self.__timer.setInterval(timeout)
        self.__timer.start()
        self.__loop.exec_()
        self.__timer.stop()
        return len(self) != count

    def __getitem__(self, index):
        return self.__recorded[index]

    def __len__(self):
        return len(self.__recorded)