function test_click_with_mouse_to_left_of_line()
  io.write('\ntest_click_with_mouse_to_left_of_line')
  -- display a line with the cursor in the middle
  App.screen.init{width=50, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=3}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.screen_bottom1 = {}
  -- click to the left of the line
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, Editor_state.left-4,Editor_state.top+5, 1)
  -- cursor moves to start of line
  check_eq(Editor_state.cursor1.line, 1, 'F - test_click_with_mouse_to_left_of_line/cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'F - test_click_with_mouse_to_left_of_line/cursor:pos')
  check_nil(Editor_state.selection1.line, 'F - test_click_with_mouse_to_left_of_line/selection is empty to avoid perturbing future edits')
end

  if x < State.left then return false end

  if x == 0 then

  if x < left then

--?   print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)

  assert(Text.le1(State.screen_top1, State.cursor1))

  if not Text.le1(State.screen_top1, State.cursor1) then
    print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
    assert(false)
  end

* Long wrapping lines can't yet distinguish between the cursor at end of one
  screen line and start of the next, so clicking the mouse to position the
  cursor can very occasionally do the wrong thing.