move the startpoint into its own function

borg_qt/__main__.py

@@ -6,8 +6,7 @@ from PyQt5.QtWidgets import QApplication
 from borg_qt.main_window import MainWindow
 from borg_qt.helper import get_parser
 
-
-if __name__ == "__main__":
+def main():
     app = QApplication(sys.argv)
     window = MainWindow()
     parser = get_parser()
@@ -21,3 +20,6 @@ if __name__ == "__main__":
         window.start()
 
         sys.exit(app.exec_())
+
+if __name__ == "__main__":
+    main()