Coverage QThread Test

test.py

import time

from PyQt5.QtCore import QThread


class Worker(QThread):

    def __init__(self):
        QThread.__init__(self)
        self.counter = 0

    def run(self):
        import threading, sys
        sys.settrace(threading._trace_hook)
        while not self.isInterruptionRequested():
            self.calculate()
            self.msleep(33) # 30Hz

    def calculate(self):
        self.counter += 1


def main():
    w = Worker()
    w.start()
    assert w.isRunning()
    time.sleep(2)    
    w.requestInterruption()
    w.wait()
    assert w.isFinished()
    assert w.counter > 0
    print("Counter: ", w.counter)


if __name__ == "__main__":
    main()

Change main to "test_main" and then run under pytest.... notice you get coverage for the counter? but you won't get coverage for run.