I want the topmost y coordinate for a given screen line.
I think.
373DPSGOWSKPO2MURUMKIZBCI7RRJWQLQ56PWFYTQCRIF5AJIBPQC
test_y_of_schema1 = function()
local state = edit.initialize_test_state()
state.lines = load_array{'1', '2', '3'}
Text.redraw_all(state)
check_eq(y_of_schema1(state, {line=1, pos=1}), 0, 'start of first line')
check_eq(y_of_schema1(state, {line=1, pos=2}), 0, 'middle of first line')
check_eq(y_of_schema1(state, {line=2, pos=2}), state.line_height, 'middle of second line')
end