Try to assert that the pudb ctrl+p interaction works as intended.

test3.py

#!/usr/bin/env python
"pudb test script"

def main():
    "The entry point"
    from pudb.debugger import Debugger
    import urwid.html_fragment

    dbg = Debugger()

    screen = urwid.html_fragment.HtmlGenerator()
    screen.sizes = [ (80, 24) ] *2
    screen.keys = [ ("ctrl p",) ]

    dbg.ui.screen = screen
    dbg.ui.setup_palette(screen)

    try:
        dbg._runscript('trivial.py')
    except urwid.main_loop.ExitMainLoop:
        pass

    # Show the equivalent html.
    #print '\n'.join(screen.fragments)

    assert dbg.ui.preferences.shown == True

main()

I'm assuming the contents of trivial.py don't matter here.