# every pane open splits ONE existing pane, the rest of the column keeps its
# sizes: Alt-n splits the active pane, a looked-up file stacking top-left
# splits only the old top pane, an execute-spawned shell for a file's dir
# splits only the bottom pane of the rightmost column
dirmk sub
file sub/f.txt echo 'TTY'OK
start 30 100 -n 3
wait 8000 sub
stable 700 20000
# give pane 0 (top-left) some content so its content-height split is visible
press left 5 8
release left 5 8
stable 400 5000
key i
text echo one; echo two
key enter
key esc
settle 700
stable 400 5000
snap before
# Alt-n: new shell below pane 0 — the bottom pane's boundary must not move
key a-n
stable 700 15000
snap altn-left
# make the right column two panes (Alt-n in a fresh column, trivial split)
press left 70 8
release left 70 8
stable 400 5000
key a-n
stable 700 15000
snap altn-right
# look sub/f.txt from the bottom-left shell: the doc stacks at the top of the
# left column, splitting only the old top pane — lower boundaries must not move
press left 5 27
release left 5 27
stable 400 5000
key i
text sub/f.txt
key esc
settle 700
stable 400 5000
press right 7 27
release right 7 27
stable 700 15000
snap file-open
# execute the file's command (middle drag over line 1): no shell has cwd sub/,
# so one is forked at the bottom of the rightmost column, splitting only the
# pane above it
press middle 8 3
drag middle 19 3
release middle 19 3
wait 10000 TTYOK
motion 40 25
stable 700 10000
snap ttydir