Status bar messages to indicate rendering and viewing progress

[mbway]

since the application doesn't look visually different when it is rendering/drawing and when you can interact with it, I think it would be useful if there was some way to determine if CQ-Editor is currently busy at a glance. The status bar isn't currently being used for anything so I used that to display messages:

time.sleep(1.5)  # to simulate a long running script
sphere = cq.Workplane('XY').move(6, 6).sphere(3)
loft = cq.Workplane('XY').ellipse(5, 7).workplane(5).circle(4).workplane(5).ellipse(7, 5).loft()
box = cq.Workplane('XY').move(-8, -2).box(3, 4, 2)

show_object(loft, 'my_loft')
show_object(sphere, 'my_sphere')
show_object(box, 'my_box')

https://user-images.githubusercontent.com/4923501/108626297-4c81b100-7447-11eb-806c-0af038f160d2.mp4

[mbway]

It seems to be because I'm calling QApplication.processEvents() inside set_status_message() some unit tests are failing. This is currently required for the status messages to be visible as rendering blocks the main thread.

In the test_console() unit test from master (which passes) if I insert these two lines:

    # test print_text
    pos_orig = console._prompt_pos
    console.print_text('a')
    
+    from PyQt5.QtWidgets import QApplication
+    QApplication.processEvents()
    
    assert(console._prompt_pos == pos_orig + len('a'))

then the test fails because the prompt is printed

print(repr(console._control.document().toPlainText()))
'a\n\nIn [1]: \n\nIn [2]: '

and with processEvents called inside set_status_message the content is: '\nIn [1]: a'

Any advice on how best to handle this? should I update the unit tests or find another workaround (not that I can think of any)