https://github.com/akkartik/mu/blob/master/083scenario_screen_test.mu

     1 # To check our support for screens in scenarios, rewrite tests from print.mu
     2
     3 scenario print-character-at-top-left-2 [
     4   local-scope
     5   assume-screen 3/width, 2/height
     6   run [
     7     a:char <- copy 97/a
     8     screen <- print screen, a
     9   ]
    10   screen-should-contain [
    11     .a  .
    12     .   .
    13   ]
    14 ]
    15
    16 scenario clear-line-erases-printed-characters-2 [
    17   local-scope
    18   assume-screen 5/width, 3/height
    19   # print a character
    20   a:char <- copy 97/a
    21   screen <- print screen, a
    22   # move cursor to start of line
    23   screen <- move-cursor screen, 0/row, 0/column
    24   run [
    25     screen <- clear-line screen
    26   ]
    27   screen-should-contain [
    28     .     .
    29     .     .
    30     .     .
    31   ]
    32 ]
    33
    34 scenario scroll-screen [
    35   local-scope
    36   assume-screen 3/width, 2/height
    37   run [
    38     a:char <- copy 97/a
    39     move-cursor screen, 1/row, 2/column
    40     screen <- print screen, a
    41     screen <- print screen, a
    42   ]
    43   screen-should-contain [
    44     .  a.
    45     .a  .
    46   ]
    47 ]