--
-- I'm checking the precise state of the screen in this file, an inherently
-- brittle approach that depends on details of the font and text shaping
-- algorithms used by a particular release of LÖVE.
--
-- (This brittleness is one reason lines2 and its forks have no tests.)
--
-- To manage the brittleness, there'll be one version of this file for each
-- distinct LÖVE version that introduces font changes.
Version, Major_version = App.love_version()
if Major_version == 11 then
  load_file_from_source_or_save_directory('source_text_tests_love11.lua')
elseif Major_version == 12 then
  -- not released/stable yet
  load_file_from_source_or_save_directory('source_text_tests_love12.lua')
end

--?       -- render screen line
--?       App.color(Text_color)
--?       App.screen.print(screen_line, State.left,y)
  for pos,char in utf8chars(line.data) do
    local w = State.font:getWidth(char)
    if Text.should_word_wrap(State, line.data, pos, char, x)
        or x+w > State.width  -- truncate within a word
    then
      x = 0
    x = x + w
  end
end
-- Check whether to word-wrap line at pos which will be positioned at x.
--
-- We wrap at the start of a word (non-space just after space) if the word
-- (non-spaces followed by spaces) wouldn't fit in the rest of the line.
--
-- x lies between 0 and editor.width.
--
-- Postcondition:
--  Current line is not wider than editor.width
--
-- Desired properties in priority order:
--  Next line doesn't start with whitespace
--  Current line ends with whitespace (a.k.a. word wrap)
--  Current line is close to full
-- None of these is guaranteed. But we should never satisfy a lower priority
-- before a higher one.
function Text.should_word_wrap(editor, line, pos, char, x)
  if char:match('%s') then return false end
  if pos == 1 then return false end
  if Text.match(line, pos-1, '%S') then return false end
  local offset = Text.offset(line, pos)
  -- most of the time a word is printable chars + whitespace
  local s = line:match('%S+%s*', offset)
  assert(s)
  local w = editor.font:getWidth(s)
  if x+w < editor.width then return false end
  if w > editor.width then return false end  -- we're going to need to truncate the next word anyway
  if x < 0.8*editor.width then
    local s2 = line:match('%S+', offset)
    local w2 = editor.font:getWidth(s2)
    if x+w2 > editor.width then
      -- there'll be some non-whitespace left over for the next line
      return false
    end
  return true
  --== shortcuts that mutate text (must schedule_save)
end
-- create a new iterator for s which provides the index and UTF-8 bytes corresponding to each codepoint
function utf8chars(s, startpos)
  local next_pos = startpos or 1  -- in code points
  local next_offset = utf8.offset(s, next_pos)  -- in bytes
  return function()
    assert(next_offset)  -- never call the iterator after it returns nil
    local curr_pos = next_pos
    next_pos = next_pos+1
    local curr_offset = next_offset
    next_offset = utf8.offset(s, 2, next_offset)
    if next_offset == nil then return end
    local curr_char = s:sub(curr_offset, next_offset-1)
    return curr_pos, curr_char
  end
end
  if chord == 'return' then
    local before_line = State.cursor1.line
    local before = snapshot(State, before_line)
    Text.insert_return(State)
end
  end
    end
      table.insert(line_cache.screen_line_starting_pos, pos)
      -- render colorized text
      local x = State.left
      for frag in screen_line:gmatch('%S*%s*') do
        select_color(frag)
        App.screen.print(frag, x,y)

function edit.update_font_settings(State, font_height, font)
  State.font = font or love.graphics.newFont(State.font_height)
  State.line_height = math.floor(font_height*1.3)
  State.font_height = font_height

end
function test_click_to_create_drawing()
  App.screen.init{width=800, height=600}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{}
  Text.redraw_all(Editor_state)
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, 8,Editor_state.top+8, 1)
  -- cursor skips drawing to always remain on text
  check_eq(#Editor_state.lines, 2, '#lines')
  check_eq(Editor_state.cursor1.line, 2, 'cursor')

function test_backspace_to_delete_drawing()
  -- display a drawing followed by a line of text (you shouldn't ever have a drawing right at the end)
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'```lines', '```', ''}
  Text.redraw_all(Editor_state)
  -- cursor is on text as always (outside tests this will get initialized correctly)
  Editor_state.cursor1.line = 2
  -- backspacing deletes the drawing
  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
  check_eq(#Editor_state.lines, 1, '#lines')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
end

end
function test_pagedown_skips_drawings()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'def',               -- height 15
                                  'ghi'}               -- height 15
  Text.redraw_all(Editor_state)
  check_eq(Editor_state.lines[2].mode, 'drawing', 'baseline/lines')
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  -- initially the screen displays the first line and the drawing
  -- 15px margin + 15px line1 + 10px margin + 25px drawing + 10px margin = 75px < screen height 80px
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  -- after pagedown the screen draws the drawing up top
  -- 15px margin + 10px margin + 25px drawing + 10px margin + 15px line3 = 75px < screen height 80px
  edit.run_after_keychord(Editor_state, 'pagedown', 'pagedown')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'cursor')
  y = Editor_state.top + drawing_height
  App.screen.check(y, 'def', 'screen:1')

function test_down_arrow_skips_drawing()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=100}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  y = y + drawing_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  check(Editor_state.cursor_x, 'baseline/cursor_x')
  -- after hitting the down arrow the cursor moves down by 2 lines, skipping the drawing
  edit.run_after_keychord(Editor_state, 'down', 'down')
  check_eq(Editor_state.cursor1.line, 3, 'cursor')
end

function test_up_arrow_skips_drawing()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=100}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  y = y + drawing_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  check(Editor_state.cursor_x, 'baseline/cursor_x')
  -- after hitting the up arrow the cursor moves up by 2 lines, skipping the drawing
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
end

end
function test_up_arrow_scrolls_up_by_one_line_skipping_drawing()
  -- display lines 3/4/5 with a drawing just off screen at line 2
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', '```lines', '```', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=3, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'def', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up to previous text line
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')

end
function test_click_to_create_drawing()
  App.screen.init{width=800, height=600}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{}
  Text.redraw_all(Editor_state)
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, 8,Editor_state.top+8, 1)
  -- cursor skips drawing to always remain on text
  check_eq(#Editor_state.lines, 2, '#lines')
  check_eq(Editor_state.cursor1.line, 2, 'cursor')
end
function test_backspace_to_delete_drawing()
  -- display a drawing followed by a line of text (you shouldn't ever have a drawing right at the end)
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'```lines', '```', ''}
  Text.redraw_all(Editor_state)
  -- cursor is on text as always (outside tests this will get initialized correctly)
  Editor_state.cursor1.line = 2
  -- backspacing deletes the drawing
  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
  check_eq(#Editor_state.lines, 1, '#lines')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')

function test_pagedown_skips_drawings()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'def',               -- height 15
                                  'ghi'}               -- height 15
  Text.redraw_all(Editor_state)
  check_eq(Editor_state.lines[2].mode, 'drawing', 'baseline/lines')
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  -- initially the screen displays the first line and the drawing
  -- 15px margin + 15px line1 + 10px margin + 25px drawing + 10px margin = 75px < screen height 80px
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  -- after pagedown the screen draws the drawing up top
  -- 15px margin + 10px margin + 25px drawing + 10px margin + 15px line3 = 75px < screen height 80px
  edit.run_after_keychord(Editor_state, 'pagedown', 'pagedown')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'cursor')
  y = Editor_state.top + drawing_height
  App.screen.check(y, 'def', 'screen:1')
end

function test_down_arrow_skips_drawing()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=100}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  y = y + drawing_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  check(Editor_state.cursor_x, 'baseline/cursor_x')
  -- after hitting the down arrow the cursor moves down by 2 lines, skipping the drawing
  edit.run_after_keychord(Editor_state, 'down', 'down')
  check_eq(Editor_state.cursor1.line, 3, 'cursor')
end

end
function test_up_arrow_skips_drawing()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=100}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  y = y + drawing_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  check(Editor_state.cursor_x, 'baseline/cursor_x')
  -- after hitting the up arrow the cursor moves up by 2 lines, skipping the drawing
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')

function test_up_arrow_scrolls_up_by_one_line_skipping_drawing()
  -- display lines 3/4/5 with a drawing just off screen at line 2
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', '```lines', '```', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=3, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'def', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up to previous text line
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
end

  Editor_state.lines = load_array{'```lines', '```', 'def', 'ghi', '’deg'}  -- contains unicode quote in final line

  Editor_state.lines = load_array{'abc', 'def', 'ghi', '’deg'}  -- contains unicode quote in final line

  check_eq(#Editor_state.lines, 1, '#lines')
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top:line')
  check_eq(Editor_state.screen_top1.pos, 1, 'screen_top:pos')
  App.screen.check(y, 'ghi', 'screen:2')

  edit.run_after_text_input(Editor_state, 'x')
  check_eq(Editor_state.lines[1].data, 'xbc', 'baseline')
  check_nil(Editor_state.selection1.line, 'baseline:selection')
  Editor_state.lines = load_array{'abc', 'def', 'ghi', '’deg'}  -- contains unicode quote in final line

  for frag in line.data:gmatch('%S*%s*') do
    local frag_width = State.font:getWidth(frag)

-- Arguably this should be called source_edit_tests.lua,
-- but that would mess up the git blame at this point.
function test_initial_state()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{}
  Text.redraw_all(Editor_state)
  edit.draw(Editor_state)
  check_eq(#Editor_state.lines, 1, '#lines')
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top:line')
  check_eq(Editor_state.screen_top1.pos, 1, 'screen_top:pos')
end
function test_click_to_create_drawing()
  App.screen.init{width=800, height=600}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{}
  Text.redraw_all(Editor_state)
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, 8,Editor_state.top+8, 1)
  -- cursor skips drawing to always remain on text
  check_eq(#Editor_state.lines, 2, '#lines')
  check_eq(Editor_state.cursor1.line, 2, 'cursor')
end
function test_backspace_to_delete_drawing()
  -- display a drawing followed by a line of text (you shouldn't ever have a drawing right at the end)
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'```lines', '```', ''}
  Text.redraw_all(Editor_state)
  -- cursor is on text as always (outside tests this will get initialized correctly)
  Editor_state.cursor1.line = 2
  -- backspacing deletes the drawing
  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
  check_eq(#Editor_state.lines, 1, '#lines')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
end
function test_backspace_from_start_of_final_line()
  -- display final line of text with cursor at start of it
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def'}
  Editor_state.screen_top1 = {line=2, pos=1}
  Editor_state.cursor1 = {line=2, pos=1}
  Text.redraw_all(Editor_state)
  -- backspace scrolls up
  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
  check_eq(#Editor_state.lines, 1, '#lines')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
end
function test_insert_first_character()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{}
  Text.redraw_all(Editor_state)
  edit.draw(Editor_state)
  edit.run_after_text_input(Editor_state, 'a')
  local y = Editor_state.top
  App.screen.check(y, 'a', 'screen:1')
end
function test_press_ctrl()
  -- press ctrl while the cursor is on text
  App.screen.init{width=50, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{''}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.run_after_keychord(Editor_state, 'C-m', 'm')
end
function test_move_left()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'a'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=2}
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'left', 'left')
  check_eq(Editor_state.cursor1.pos, 1, 'check')
end
function test_move_right()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'a'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'right', 'right')
  check_eq(Editor_state.cursor1.pos, 2, 'check')
end
function test_move_left_to_previous_line()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'left', 'left')
  check_eq(Editor_state.cursor1.line, 1, 'line')
  check_eq(Editor_state.cursor1.pos, 4, 'pos')  -- past end of line
end
function test_move_right_to_next_line()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=4}  -- past end of line
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'right', 'right')
  check_eq(Editor_state.cursor1.line, 2, 'line')
  check_eq(Editor_state.cursor1.pos, 1, 'pos')
end
function test_move_to_start_of_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=3}
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-left', 'left')
  check_eq(Editor_state.cursor1.pos, 1, 'check')
end
function test_move_to_start_of_previous_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=4}  -- at the space between words
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-left', 'left')
  check_eq(Editor_state.cursor1.pos, 1, 'check')
end
function test_skip_to_previous_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=5}  -- at the start of second word
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-left', 'left')
  check_eq(Editor_state.cursor1.pos, 1, 'check')
end
function test_skip_past_tab_to_previous_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def\tghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=10}  -- within third word
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-left', 'left')
  check_eq(Editor_state.cursor1.pos, 9, 'check')
end
function test_skip_multiple_spaces_to_previous_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc  def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=6}  -- at the start of second word
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-left', 'left')
  check_eq(Editor_state.cursor1.pos, 1, 'check')
end
function test_move_to_start_of_word_on_previous_line()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def', 'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-left', 'left')
  check_eq(Editor_state.cursor1.line, 1, 'line')
  check_eq(Editor_state.cursor1.pos, 5, 'pos')
end
function test_move_past_end_of_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-right', 'right')
  check_eq(Editor_state.cursor1.pos, 4, 'check')
end
function test_skip_to_next_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=4}  -- at the space between words
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-right', 'right')
  check_eq(Editor_state.cursor1.pos, 8, 'check')
end
function test_skip_past_tab_to_next_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc\tdef'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}  -- at the space between words
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-right', 'right')
  check_eq(Editor_state.cursor1.pos, 4, 'check')
end
function test_skip_multiple_spaces_to_next_word()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc  def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=4}  -- at the start of second word
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-right', 'right')
  check_eq(Editor_state.cursor1.pos, 9, 'check')
end
function test_move_past_end_of_word_on_next_line()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def', 'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=8}
  edit.draw(Editor_state)
  edit.run_after_keychord(Editor_state, 'M-right', 'right')
  check_eq(Editor_state.cursor1.line, 2, 'line')
  check_eq(Editor_state.cursor1.pos, 4, 'pos')
end
function test_click_moves_cursor()
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'xyz'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
  -- selection is empty to avoid perturbing future edits
  check_nil(Editor_state.selection1.line, 'selection:line')
  check_nil(Editor_state.selection1.pos, 'selection:pos')
end
function test_click_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.selection1 = {}
  -- 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, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  check_nil(Editor_state.selection1.line, 'selection is empty to avoid perturbing future edits')
end
function test_click_takes_margins_into_account()
  -- display two lines with cursor on one of them
  App.screen.init{width=100, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.left = 50  -- occupy only right side of screen
  Editor_state.lines = load_array{'abc', 'def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  -- click on the other line
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- cursor moves
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
  check_nil(Editor_state.selection1.line, 'selection is empty to avoid perturbing future edits')
end
function test_click_on_empty_line()
  -- display two lines with the first one empty
  App.screen.init{width=50, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'', 'def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  -- click on the empty line
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- cursor moves
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
  -- selection remains empty
  check_nil(Editor_state.selection1.line, 'selection is empty to avoid perturbing future edits')
end
function test_click_below_final_line_of_file()
  -- display one line
  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=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  -- click below first line
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, Editor_state.left+8,Editor_state.top+50, 1)
  -- cursor goes to bottom
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 4, 'cursor:pos')
  -- selection remains empty
  check_nil(Editor_state.selection1.line, 'selection is empty to avoid perturbing future edits')
end
function test_draw_text()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:3')
end
function test_draw_wrapping_text()
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'defgh', 'xyz'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'de', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'fgh', 'screen:3')
end
function test_draw_word_wrapping_text()
  App.screen.init{width=60, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc ', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def ', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:3')
end
function test_click_on_wrapping_line()
  -- display two screen lines with cursor on one of them
  App.screen.init{width=50, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def ghi jkl mno pqr stu'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=20}
  Editor_state.screen_top1 = {line=1, pos=1}
  -- click on the other line
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- cursor moves
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
  check_nil(Editor_state.selection1.line, 'selection is empty to avoid perturbing future edits')
end
function test_click_on_wrapping_line_takes_margins_into_account()
  -- display two screen lines with cursor on one of them
  App.screen.init{width=100, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.left = 50  -- occupy only right side of screen
  Editor_state.lines = load_array{'abc def ghi jkl mno pqr stu'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=20}
  Editor_state.screen_top1 = {line=1, pos=1}
  -- click on the other line
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- cursor moves
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
  check_nil(Editor_state.selection1.line, 'selection is empty to avoid perturbing future edits')
end
function test_draw_text_wrapping_within_word()
  -- arrange a screen line that needs to be split within a word
  App.screen.init{width=60, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abcd e fghijk', 'xyz'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abcd ', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'e fgh', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ijk', 'screen:3')
end
function test_draw_wrapping_text_containing_non_ascii()
  -- draw a long line containing non-ASCII
  App.screen.init{width=60, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'madam I’m adam', 'xyz'}  -- notice the non-ASCII apostrophe
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'mad', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'am I', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, '’m a', 'screen:3')
end
function test_click_past_end_of_screen_line()
  -- display a wrapping line
  App.screen.init{width=75, height=80}
  Editor_state = edit.initialize_test_state()
                               --  12345678901234
  Editor_state.lines = load_array{"madam I'm adam"}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'madam ', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, "I'm ad", 'baseline/screen:2')
  y = y + Editor_state.line_height
  -- click past end of second screen line
  edit.run_after_mouse_click(Editor_state, App.screen.width-2,y-2, 1)
  -- cursor moves to end of screen line (one more than final character shown)
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 13, 'cursor:pos')
end
function test_click_on_wrapping_line_rendered_from_partway_at_top_of_screen()
  -- display a wrapping line from its second screen line
  App.screen.init{width=75, height=80}
  Editor_state = edit.initialize_test_state()
                               --  12345678901234
  Editor_state.lines = load_array{"madam I'm adam"}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=8}
  Editor_state.screen_top1 = {line=1, pos=7}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, "I'm ad", 'baseline/screen:2')
  y = y + Editor_state.line_height
  -- click past end of second screen line
  edit.run_after_mouse_click(Editor_state, App.screen.width-2,y-2, 1)
  -- cursor moves to end of screen line (one more than final character shown)
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 13, 'cursor:pos')
end
function test_click_past_end_of_wrapping_line()
  -- display a wrapping line
  App.screen.init{width=75, height=80}
  Editor_state = edit.initialize_test_state()
                               --  12345678901234
  Editor_state.lines = load_array{"madam I'm adam"}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'madam ', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, "I'm ad", 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'am', 'baseline/screen:3')
  y = y + Editor_state.line_height
  -- click past the end of it
  edit.run_after_mouse_click(Editor_state, App.screen.width-2,y-2, 1)
  -- cursor moves to end of line
  check_eq(Editor_state.cursor1.pos, 15, 'cursor')  -- one more than the number of UTF-8 code-points
end
function test_click_past_end_of_wrapping_line_containing_non_ascii()
  -- display a wrapping line containing non-ASCII
  App.screen.init{width=75, height=80}
  Editor_state = edit.initialize_test_state()
                               --  12345678901234
  Editor_state.lines = load_array{'madam I’m adam'}  -- notice the non-ASCII apostrophe
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'madam ', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'I’m ad', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'am', 'baseline/screen:3')
  y = y + Editor_state.line_height
  -- click past the end of it
  edit.run_after_mouse_click(Editor_state, App.screen.width-2,y-2, 1)
  -- cursor moves to end of line
  check_eq(Editor_state.cursor1.pos, 15, 'cursor')  -- one more than the number of UTF-8 code-points
end
function test_click_past_end_of_word_wrapping_line()
  -- display a long line wrapping at a word boundary on a screen of more realistic length
  App.screen.init{width=160, height=80}
  Editor_state = edit.initialize_test_state()
                                -- 0        1         2
                                -- 123456789012345678901
  Editor_state.lines = load_array{'the quick brown fox jumped over the lazy dog'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'the quick brown fox ', 'baseline/screen:1')
  y = y + Editor_state.line_height
  -- click past the end of the screen line
  edit.run_after_mouse_click(Editor_state, App.screen.width-2,y-2, 1)
  -- cursor moves to end of screen line (one more than final character shown)
  check_eq(Editor_state.cursor1.pos, 21, 'cursor')
end
function test_select_text()
  -- display a line of text
  App.screen.init{width=75, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  -- select a letter
  App.fake_key_press('lshift')
  edit.run_after_keychord(Editor_state, 'S-right', 'right')
  App.fake_key_release('lshift')
  edit.key_release(Editor_state, 'lshift')
  -- selection persists even after shift is released
  check_eq(Editor_state.selection1.line, 1, 'selection:line')
  check_eq(Editor_state.selection1.pos, 1, 'selection:pos')
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
end
function test_cursor_movement_without_shift_resets_selection()
  -- display a line of text with some part selected
  App.screen.init{width=75, 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=1}
  Editor_state.selection1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  -- press an arrow key without shift
  edit.run_after_keychord(Editor_state, 'right', 'right')
  -- no change to data, selection is reset
  check_nil(Editor_state.selection1.line, 'check')
  check_eq(Editor_state.lines[1].data, 'abc', 'data')
end
function test_edit_deletes_selection()
  -- display a line of text with some part selected
  App.screen.init{width=75, 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=1}
  Editor_state.selection1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  -- press a key
  edit.run_after_text_input(Editor_state, 'x')
  -- selected text is deleted and replaced with the key
  check_eq(Editor_state.lines[1].data, 'xbc', 'check')
end
function test_edit_with_shift_key_deletes_selection()
  -- display a line of text with some part selected
  App.screen.init{width=75, 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=1}
  Editor_state.selection1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  -- mimic precise keypresses for a capital letter
  App.fake_key_press('lshift')
  edit.keychord_press(Editor_state, 'd', 'd')
  edit.text_input(Editor_state, 'D')
  edit.key_release(Editor_state, 'd')
  App.fake_key_release('lshift')
  -- selected text is deleted and replaced with the key
  check_nil(Editor_state.selection1.line, 'check')
  check_eq(Editor_state.lines[1].data, 'Dbc', 'data')
end
function test_copy_does_not_reset_selection()
  -- display a line of text with a selection
  App.screen.init{width=75, 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=1}
  Editor_state.selection1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  -- copy selection
  edit.run_after_keychord(Editor_state, 'C-c', 'c')
  check_eq(App.clipboard, 'a', 'clipboard')
  -- selection is reset since shift key is not pressed
  check(Editor_state.selection1.line, 'check')
end
function test_cut()
  -- display a line of text with some part selected
  App.screen.init{width=75, 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=1}
  Editor_state.selection1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  -- press a key
  edit.run_after_keychord(Editor_state, 'C-x', 'x')
  check_eq(App.clipboard, 'a', 'clipboard')
  -- selected text is deleted
  check_eq(Editor_state.lines[1].data, 'bc', 'data')
end
function test_paste_replaces_selection()
  -- display a line of text with a selection
  App.screen.init{width=75, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.selection1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  -- set clipboard
  App.clipboard = 'xyz'
  -- paste selection
  edit.run_after_keychord(Editor_state, 'C-v', 'v')
  -- selection is reset since shift key is not pressed
  -- selection includes the newline, so it's also deleted
  check_eq(Editor_state.lines[1].data, 'xyzdef', 'check')
end
function test_deleting_selection_may_scroll()
  -- display lines 2/3/4
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=2}
  Editor_state.screen_top1 = {line=2, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'def', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'baseline/screen:3')
  -- set up a selection starting above the currently displayed page
  Editor_state.selection1 = {line=1, pos=2}
  -- delete selection
  edit.run_after_keychord(Editor_state, 'backspace', 'backspace')
  -- page scrolls up
  check_eq(Editor_state.screen_top1.line, 1, 'check')
  check_eq(Editor_state.lines[1].data, 'ahi', 'data')
end
function test_edit_wrapping_text()
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'xyz'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=4}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  edit.run_after_text_input(Editor_state, 'g')
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'de', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'fg', 'screen:3')
end
function test_insert_newline()
  -- display a few lines
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  -- hitting the enter key splits the line
  edit.run_after_keychord(Editor_state, 'return', 'return')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'a', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'bc', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:3')
end
function test_insert_newline_at_start_of_line()
  -- display a line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  -- hitting the enter key splits the line
  edit.run_after_keychord(Editor_state, 'return', 'return')
  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  check_eq(Editor_state.lines[1].data, '', 'data:1')
  check_eq(Editor_state.lines[2].data, 'abc', 'data:2')
end
function test_insert_from_clipboard()
  -- display a few lines
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  -- paste some text including a newline, check that new line is created
  App.clipboard = 'xy\nz'
  edit.run_after_keychord(Editor_state, 'C-v', 'v')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'axy', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'zbc', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:3')
end
function test_select_text_using_mouse()
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'xyz'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  -- press and hold on first location
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- drag and release somewhere else
  edit.run_after_mouse_release(Editor_state, Editor_state.left+20,Editor_state.top+Editor_state.line_height+5, 1)
  check_eq(Editor_state.selection1.line, 1, 'selection:line')
  check_eq(Editor_state.selection1.pos, 2, 'selection:pos')
  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 4, 'cursor:pos')
end
function test_select_text_using_mouse_starting_above_text()
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'xyz'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  -- press mouse above first line of text
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,5, 1)
  check(Editor_state.selection1.line ~= nil, 'selection:line-not-nil')
  check_eq(Editor_state.selection1.line, 1, 'selection:line')
  check_eq(Editor_state.selection1.pos, 1, 'selection:pos')
end
function test_select_text_using_mouse_starting_above_text_wrapping_line()
  -- first screen line starts in the middle of a line
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'defgh', 'xyz'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=5}
  Editor_state.screen_top1 = {line=2, pos=3}
  -- press mouse above first line of text
  edit.draw(Editor_state)
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,5, 1)
  -- selection is at screen top
  check(Editor_state.selection1.line ~= nil, 'selection:line-not-nil')
  check_eq(Editor_state.selection1.line, 2, 'selection:line')
  check_eq(Editor_state.selection1.pos, 3, 'selection:pos')
end
function test_select_text_using_mouse_starting_below_text()
  -- I'd like to test what happens when a mouse click is below some page of
  -- text, potentially even in the middle of a line.
  -- However, it's brittle to set up a text line boundary just right.
  -- So I'm going to just check things below the bottom of the final line of
  -- text when it's in the middle of the screen.
  -- final screen line ends in the middle of screen
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abcde'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'ab', 'baseline:screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'cde', 'baseline:screen:2')
  -- press mouse above first line of text
  edit.run_after_mouse_press(Editor_state, 5,App.screen.height-5, 1)
  -- selection is past bottom-most text in screen
  check(Editor_state.selection1.line ~= nil, 'selection:line-not-nil')
  check_eq(Editor_state.selection1.line, 1, 'selection:line')
  check_eq(Editor_state.selection1.pos, 6, 'selection:pos')
end
function test_select_text_using_mouse_and_shift()
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'xyz'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  -- click on first location
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- hold down shift and click somewhere else
  App.fake_key_press('lshift')
  edit.run_after_mouse_press(Editor_state, Editor_state.left+20,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+20,Editor_state.top+Editor_state.line_height+5, 1)
  App.fake_key_release('lshift')
  check_eq(Editor_state.selection1.line, 1, 'selection:line')
  check_eq(Editor_state.selection1.pos, 2, 'selection:pos')
  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 4, 'cursor:pos')
end
function test_select_text_repeatedly_using_mouse_and_shift()
  App.screen.init{width=50, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'xyz'}
  Text.redraw_all(Editor_state)
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  -- click on first location
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- hold down shift and click on a second location
  App.fake_key_press('lshift')
  edit.run_after_mouse_press(Editor_state, Editor_state.left+20,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+20,Editor_state.top+Editor_state.line_height+5, 1)
  -- hold down shift and click at a third location
  App.fake_key_press('lshift')
  edit.run_after_mouse_press(Editor_state, Editor_state.left+20,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+Editor_state.line_height+5, 1)
  App.fake_key_release('lshift')
  -- selection is between first and third location. forget the second location, not the first.
  check_eq(Editor_state.selection1.line, 1, 'selection:line')
  check_eq(Editor_state.selection1.pos, 2, 'selection:pos')
  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
end
function test_select_all_text()
  -- display a single line of text
  App.screen.init{width=75, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  -- select all
  App.fake_key_press('lctrl')
  edit.run_after_keychord(Editor_state, 'C-a', 'a')
  App.fake_key_release('lctrl')
  edit.key_release(Editor_state, 'lctrl')
  -- selection
  check_eq(Editor_state.selection1.line, 1, 'selection:line')
  check_eq(Editor_state.selection1.pos, 1, 'selection:pos')
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 8, 'cursor:pos')
end
function test_cut_without_selection()
  -- display a few lines
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.selection1 = {}
  edit.draw(Editor_state)
  -- try to cut without selecting text
  edit.run_after_keychord(Editor_state, 'C-x', 'x')
  -- no crash
  check_nil(Editor_state.selection1.line, 'check')
end
function test_pagedown()
  App.screen.init{width=120, height=45}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  -- initially the first two lines are displayed
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  -- after pagedown the bottom line becomes the top
  edit.run_after_keychord(Editor_state, 'pagedown', 'pagedown')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 2, 'cursor')
  y = Editor_state.top
  App.screen.check(y, 'def', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:2')
end
function test_pagedown_skips_drawings()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=80}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'def',               -- height 15
                                  'ghi'}               -- height 15
  Text.redraw_all(Editor_state)
  check_eq(Editor_state.lines[2].mode, 'drawing', 'baseline/lines')
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  -- initially the screen displays the first line and the drawing
  -- 15px margin + 15px line1 + 10px margin + 25px drawing + 10px margin = 75px < screen height 80px
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  -- after pagedown the screen draws the drawing up top
  -- 15px margin + 10px margin + 25px drawing + 10px margin + 15px line3 = 75px < screen height 80px
  edit.run_after_keychord(Editor_state, 'pagedown', 'pagedown')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'cursor')
  y = Editor_state.top + drawing_height
  App.screen.check(y, 'def', 'screen:1')
end
function test_pagedown_can_start_from_middle_of_long_wrapping_line()
  -- draw a few lines starting from a very long wrapping line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def ghi jkl mno pqr stu vwx yza bcd efg hij', 'XYZ'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc ', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def ', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi ', 'baseline/screen:3')
  -- after pagedown we scroll down the very long wrapping line
  edit.run_after_keychord(Editor_state, 'pagedown', 'pagedown')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top:line')
  check_eq(Editor_state.screen_top1.pos, 9, 'screen_top:pos')
  y = Editor_state.top
  App.screen.check(y, 'ghi ', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl ', 'screen:2')
  y = y + Editor_state.line_height
  if Version == '12.0' then
    -- HACK: Maybe v12.0 uses a different font? Strange that it only causes
    -- issues in a couple of places.
    -- We'll need to rethink our tests if issues like this start to multiply.
    App.screen.check(y, 'mno ', 'screen:3')
  else
    App.screen.check(y, 'mn', 'screen:3')
  end
end
function test_pagedown_never_moves_up()
  -- draw the final screen line of a wrapping line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=9}
  Editor_state.screen_top1 = {line=1, pos=9}
  edit.draw(Editor_state)
  -- pagedown makes no change
  edit.run_after_keychord(Editor_state, 'pagedown', 'pagedown')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top:line')
  check_eq(Editor_state.screen_top1.pos, 9, 'screen_top:pos')
end
function test_down_arrow_moves_cursor()
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  -- initially the first three lines are displayed
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  -- after hitting the down arrow, the cursor moves down by 1 line
  edit.run_after_keychord(Editor_state, 'down', 'down')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 2, 'cursor')
  -- the screen is unchanged
  y = Editor_state.top
  App.screen.check(y, 'abc', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:3')
end
function test_down_arrow_skips_drawing()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=100}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=1, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  y = y + drawing_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  check(Editor_state.cursor_x, 'baseline/cursor_x')
  -- after hitting the down arrow the cursor moves down by 2 lines, skipping the drawing
  edit.run_after_keychord(Editor_state, 'down', 'down')
  check_eq(Editor_state.cursor1.line, 3, 'cursor')
end
function test_down_arrow_scrolls_down_by_one_line()
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  -- after hitting the down arrow the screen scrolls down by one line
  edit.run_after_keychord(Editor_state, 'down', 'down')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 4, 'cursor')
  y = Editor_state.top
  App.screen.check(y, 'def', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'screen:3')
end
function test_down_arrow_scrolls_down_by_one_screen_line()
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi ', 'baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the down arrow the screen scrolls down by one line
  edit.run_after_keychord(Editor_state, 'down', 'down')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 5, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'def', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi ', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'screen:3')
end
function test_down_arrow_scrolls_down_by_one_screen_line_after_splitting_within_word()
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghijkl', 'mno'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghij', 'baseline/screen:3')
  -- after hitting the down arrow the screen scrolls down by one line
  edit.run_after_keychord(Editor_state, 'down', 'down')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 5, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'def', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghij', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'kl', 'screen:3')
end
function test_pagedown_followed_by_down_arrow_does_not_scroll_screen_up()
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghijkl', 'mno'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghij', 'baseline/screen:3')
  -- after hitting pagedown the screen scrolls down to start of a long line
  edit.run_after_keychord(Editor_state, 'pagedown', 'pagedown')
  check_eq(Editor_state.screen_top1.line, 3, 'baseline2/screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'baseline2/cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'baseline2/cursor:pos')
  -- after hitting down arrow the screen doesn't scroll down further, and certainly doesn't scroll up
  edit.run_after_keychord(Editor_state, 'down', 'down')
  check_eq(Editor_state.screen_top1.line, 3, 'screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 5, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'ghij', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'kl', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'mno', 'screen:3')
end
function test_up_arrow_moves_cursor()
  -- display the first 3 lines with the cursor on the bottom line
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  -- after hitting the up arrow the cursor moves up by 1 line
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 2, 'cursor')
  -- the screen is unchanged
  y = Editor_state.top
  App.screen.check(y, 'abc', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:3')
end
function test_up_arrow_skips_drawing()
  -- some lines of text with a drawing intermixed
  local drawing_width = 50
  App.screen.init{width=Editor_state.left+drawing_width, height=100}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc',               -- height 15
                                  '```lines', '```',   -- height 25
                                  'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  local drawing_height = Drawing_padding_height + drawing_width/2  -- default
  y = y + drawing_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  check(Editor_state.cursor_x, 'baseline/cursor_x')
  -- after hitting the up arrow the cursor moves up by 2 lines, skipping the drawing
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
end
function test_up_arrow_scrolls_up_by_one_line()
  -- display the lines 2/3/4 with the cursor on line 2
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.screen_top1 = {line=2, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'def', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up by one line
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
  y = Editor_state.top
  App.screen.check(y, 'abc', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:3')
end
function test_up_arrow_scrolls_up_by_one_line_skipping_drawing()
  -- display lines 3/4/5 with a drawing just off screen at line 2
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', '```lines', '```', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=3, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'def', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up to previous text line
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
end
function test_up_arrow_scrolls_up_by_one_screen_line()
  -- display lines starting from second screen line of a line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=6}
  Editor_state.screen_top1 = {line=3, pos=5}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'jkl', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'mno', 'baseline/screen:2')
  -- after hitting the up arrow the screen scrolls up to first screen line
  edit.run_after_keychord(Editor_state, 'up', 'up')
  y = Editor_state.top
  App.screen.check(y, 'ghi ', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'mno', 'screen:3')
  check_eq(Editor_state.screen_top1.line, 3, 'screen_top:line')
  check_eq(Editor_state.screen_top1.pos, 1, 'screen_top:pos')
  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
end
function test_up_arrow_scrolls_up_to_final_screen_line()
  -- display lines starting just after a long line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def', 'ghi', 'jkl', 'mno'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.screen_top1 = {line=2, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'ghi', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'mno', 'baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up to final screen line of previous line
  edit.run_after_keychord(Editor_state, 'up', 'up')
  y = Editor_state.top
  App.screen.check(y, 'def', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'screen:3')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top:line')
  check_eq(Editor_state.screen_top1.pos, 5, 'screen_top:pos')
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 5, 'cursor:pos')
end
function test_up_arrow_scrolls_up_to_empty_line()
  -- display a screenful of text with an empty line just above it outside the screen
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'', 'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.screen_top1 = {line=2, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up by one line
  edit.run_after_keychord(Editor_state, 'up', 'up')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
  y = Editor_state.top
  -- empty first line
  y = y + Editor_state.line_height
  App.screen.check(y, 'abc', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:3')
end
function test_pageup()
  App.screen.init{width=120, height=45}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.screen_top1 = {line=2, pos=1}
  -- initially the last two lines are displayed
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'def', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:2')
  -- after pageup the cursor goes to first line
  edit.run_after_keychord(Editor_state, 'pageup', 'pageup')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
  y = Editor_state.top
  App.screen.check(y, 'abc', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:2')
end
function test_pageup_scrolls_up_by_screen_line()
  -- display the first three lines with the cursor on the bottom line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def', 'ghi', 'jkl', 'mno'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.screen_top1 = {line=2, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'ghi', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'mno', 'baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the page-up key the screen scrolls up to top
  edit.run_after_keychord(Editor_state, 'pageup', 'pageup')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'abc ', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'screen:3')
end
function test_pageup_scrolls_up_from_middle_screen_line()
  -- display a few lines starting from the middle of a line (Editor_state.cursor1.pos > 1)
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc def', 'ghi jkl', 'mno'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=5}
  Editor_state.screen_top1 = {line=2, pos=5}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'jkl', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'mno', 'baseline/screen:3')  -- line wrapping includes trailing whitespace
  -- after hitting the page-up key the screen scrolls up to top
  edit.run_after_keychord(Editor_state, 'pageup', 'pageup')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'abc ', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi ', 'screen:3')
end
function test_enter_on_bottom_line_scrolls_down()
  -- display a few lines with cursor on bottom line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=2}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  -- after hitting the enter key the screen scrolls down
  edit.run_after_keychord(Editor_state, 'return', 'return')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 4, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'def', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'g', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'hi', 'screen:3')
end
function test_enter_on_final_line_avoids_scrolling_down_when_not_at_bottom()
  -- display just the bottom line on screen
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=4, pos=2}
  Editor_state.screen_top1 = {line=4, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'jkl', 'baseline/screen:1')
  -- after hitting the enter key the screen does not scroll down
  edit.run_after_keychord(Editor_state, 'return', 'return')
  check_eq(Editor_state.screen_top1.line, 4, 'screen_top')
  check_eq(Editor_state.cursor1.line, 5, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 1, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'j', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'kl', 'screen:2')
end
function test_inserting_text_on_final_line_avoids_scrolling_down_when_not_at_bottom()
  -- display just an empty bottom line on screen
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', ''}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=2, pos=1}
  Editor_state.screen_top1 = {line=2, pos=1}
  edit.draw(Editor_state)
  -- after hitting the inserting_text key the screen does not scroll down
  edit.run_after_text_input(Editor_state, 'a')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 2, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 2, 'cursor:pos')
  local y = Editor_state.top
  App.screen.check(y, 'a', 'screen:1')
end
function test_typing_on_bottom_line_scrolls_down()
  -- display a few lines with cursor on bottom line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=4}
  Editor_state.screen_top1 = {line=1, pos=1}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'abc', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'def', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:3')
  -- after typing something the line wraps and the screen scrolls down
  edit.run_after_text_input(Editor_state, 'j')
  edit.run_after_text_input(Editor_state, 'k')
  edit.run_after_text_input(Editor_state, 'l')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 7, 'cursor:pos')
  y = Editor_state.top
  App.screen.check(y, 'def', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghij', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'kl', 'screen:3')
end

--
-- I'm checking the precise state of the screen in this file, an inherently
-- brittle approach that depends on details of the font and text shaping
-- algorithms used by a particular release of LÖVE.
--
-- (This brittleness is one reason lines2 and its forks have no tests.)
--
-- To manage the brittleness, there'll be one version of this file for each
-- distinct LÖVE version that introduces font changes.

function test_left_arrow_scrolls_up_in_wrapped_line()
  -- display lines starting from second screen line of a line
  App.screen.init{width=Editor_state.left+30, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', 'def', 'ghi jkl', 'mno'}
  Text.redraw_all(Editor_state)
  Editor_state.screen_top1 = {line=3, pos=5}
  -- cursor is at top of screen
  Editor_state.cursor1 = {line=3, pos=5}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'jkl', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'mno', 'baseline/screen:2')
  -- after hitting the left arrow the screen scrolls up to first screen line
  edit.run_after_keychord(Editor_state, 'left', 'left')
  y = Editor_state.top
  App.screen.check(y, 'ghi ', 'screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'mno', 'screen:3')
  check_eq(Editor_state.screen_top1.line, 3, 'screen_top:line')
  check_eq(Editor_state.screen_top1.pos, 1, 'screen_top:pos')
  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 4, 'cursor:pos')

Version, Major_version = App.love_version()
if Major_version == 11 then
  load_file_from_source_or_save_directory('source_text_tests_love11.lua')
elseif Major_version == 12 then
  -- not released/stable yet
  load_file_from_source_or_save_directory('source_text_tests_love12.lua')