fix(tests): needing two calls to setup a screen is cringe

Before calling "attach" a screen object is just a dummy container for
(row, col) values whose purpose is to be sent as part of the "attach"
function call anyway.

Just create the screen in an attached state directly. Keep the complete
(row, col, options) config together. It is still completely valid to
later detach and re-attach as needed, including to another session.

37 files changed, 85 insertions, 236 deletions

diff --git a/test/functional/ui/bufhl_spec.lua b/test/functional/ui/bufhl_spec.lua
index 5590db5bc4..b7cf8504ff 100644
--- a/test/functional/ui/bufhl_spec.lua
+++ b/test/functional/ui/bufhl_spec.lua
@@ -16,7 +16,6 @@ describe('Buffer highlighting', function()
     clear()
     command('syntax on')
     screen = Screen.new(40, 8)
-    screen:attach()
     screen:set_default_attr_ids({
       [1] = { bold = true, foreground = Screen.colors.Blue },
       [2] = { foreground = Screen.colors.Fuchsia }, -- String
diff --git a/test/functional/ui/cmdline_highlight_spec.lua b/test/functional/ui/cmdline_highlight_spec.lua
index 1c6f19245a..0ee994ba0a 100644
--- a/test/functional/ui/cmdline_highlight_spec.lua
+++ b/test/functional/ui/cmdline_highlight_spec.lua
@@ -24,7 +24,6 @@ end
 before_each(function()
   clear()
   screen = Screen.new(40, 8)
-  screen:attach()
   source([[
     highlight RBP1 guibg=Red
     highlight RBP2 guibg=Yellow
diff --git a/test/functional/ui/cmdline_spec.lua b/test/functional/ui/cmdline_spec.lua
index 5c9ee61db9..0221c1e0b0 100644
--- a/test/functional/ui/cmdline_spec.lua
+++ b/test/functional/ui/cmdline_spec.lua
@@ -13,19 +13,12 @@ local eq = t.eq
 local is_os = t.is_os
 local api = n.api
 
--- TODO(bfredl): make Screen.new(cols, rows, {opts}) just work already
-local function new_screen(opt)
-  local screen = Screen.new(25, 5)
-  screen:attach(opt)
-  return screen
-end
-
 local function test_cmdline(linegrid)
   local screen
 
   before_each(function()
     clear()
-    screen = new_screen({ rgb = true, ext_cmdline = true, ext_linegrid = linegrid })
+    screen = Screen.new(25, 5, { rgb = true, ext_cmdline = true, ext_linegrid = linegrid })
   end)
 
   it('works', function()
@@ -849,7 +842,7 @@ describe('cmdline redraw', function()
   local screen
   before_each(function()
     clear()
-    screen = new_screen({ rgb = true })
+    screen = Screen.new(25, 5, { rgb = true })
   end)
 
   it('with timer', function()
@@ -1014,7 +1007,7 @@ describe('statusline is redrawn on entering cmdline', function()
 
   before_each(function()
     clear()
-    screen = new_screen()
+    screen = Screen.new(25, 5)
     command('set laststatus=2')
   end)
 
@@ -1186,7 +1179,6 @@ end)
 it('tabline is not redrawn in Ex mode #24122', function()
   clear()
   local screen = Screen.new(60, 5)
-  screen:attach()
 
   exec([[
     set showtabline=2
@@ -1226,7 +1218,6 @@ describe('cmdline height', function()
 
   it('does not crash resized screen #14263', function()
     local screen = Screen.new(25, 10)
-    screen:attach()
     command('set cmdheight=9999')
     screen:try_resize(25, 5)
     assert_alive()
@@ -1247,7 +1238,6 @@ describe('cmdheight=0', function()
   before_each(function()
     clear()
     screen = Screen.new(25, 5)
-    screen:attach()
   end)
 
   it('with redrawdebug=invalid resize -1', function()
@@ -1514,7 +1504,7 @@ describe('cmdheight=0', function()
 
   it('with silent! at startup', function()
     clear { args = { '-c', 'set cmdheight=0', '-c', 'autocmd VimEnter * silent! call Foo()' } }
-    screen:attach()
+    screen = Screen.new(25, 5)
     -- doesn't crash while not displaying silent! error message
     screen:expect {
       grid = [[
@@ -1526,7 +1516,7 @@ describe('cmdheight=0', function()
 
   it('with multigrid', function()
     clear { args = { '--cmd', 'set cmdheight=0' } }
-    screen:attach { ext_multigrid = true }
+    screen = Screen.new(25, 5, { ext_multigrid = true })
     api.nvim_buf_set_lines(0, 0, -1, true, { 'p' })
     screen:expect {
       grid = [[
@@ -1689,7 +1679,7 @@ describe('cmdheight=0', function()
 
   it('can be resized with external messages', function()
     clear()
-    screen = new_screen({ rgb = true, ext_messages = true })
+    screen = Screen.new(25, 5, { rgb = true, ext_messages = true })
     command('set laststatus=2 mouse=a')
     command('resize -1')
     screen:expect([[
diff --git a/test/functional/ui/cursor_spec.lua b/test/functional/ui/cursor_spec.lua
index 619153724b..d7c0657820 100644
--- a/test/functional/ui/cursor_spec.lua
+++ b/test/functional/ui/cursor_spec.lua
@@ -12,7 +12,6 @@ describe('ui/cursor', function()
   before_each(function()
     clear()
     screen = Screen.new(25, 5)
-    screen:attach()
   end)
 
   it("'guicursor' is published as a UI event", function()
diff --git a/test/functional/ui/decorations_spec.lua b/test/functional/ui/decorations_spec.lua
index d96f614cd9..fbf16f3afe 100644
--- a/test/functional/ui/decorations_spec.lua
+++ b/test/functional/ui/decorations_spec.lua
@@ -20,7 +20,6 @@ describe('decorations providers', function()
   before_each(function()
     clear()
     screen = Screen.new(40, 8)
-    screen:attach()
     screen:set_default_attr_ids {
       [1] = {bold=true, foreground=Screen.colors.Blue};
       [2] = {foreground = Screen.colors.Grey100, background = Screen.colors.Red};
@@ -766,7 +765,6 @@ describe('extmark decorations', function()
   before_each( function()
     clear()
     screen = Screen.new(50, 15)
-    screen:attach()
     screen:set_default_attr_ids {
       [1] = {bold=true, foreground=Screen.colors.Blue};
       [2] = {foreground = Screen.colors.Brown};
@@ -2501,7 +2499,6 @@ describe('decorations: inline virtual text', function()
   before_each( function()
     clear()
     screen = Screen.new(50, 3)
-    screen:attach()
     screen:set_default_attr_ids {
       [1] = {bold=true, foreground=Screen.colors.Blue};
       [2] = {foreground = Screen.colors.Brown};
@@ -4121,7 +4118,6 @@ describe('decorations: virtual lines', function()
   before_each(function()
     clear()
     screen = Screen.new(50, 12)
-    screen:attach()
     screen:add_extra_attr_ids {
         [100] = { foreground = Screen.colors.Blue, background = Screen.colors.Yellow },
     }
@@ -5046,7 +5042,6 @@ describe('decorations: signs', function()
   before_each(function()
     clear()
     screen = Screen.new(50, 10)
-    screen:attach()
     screen:add_extra_attr_ids {
         [100] = { foreground = Screen.colors.Blue, background = Screen.colors.Yellow },
     }
@@ -5662,7 +5657,6 @@ describe('decorations: virt_text', function()
   before_each(function()
     clear()
     screen = Screen.new(50, 10)
-    screen:attach()
   end)
 
   it('avoids regression in #17638', function()
@@ -5737,7 +5731,6 @@ describe('decorations: window scoped', function()
   before_each(function()
     clear()
     screen = Screen.new(20, 10)
-    screen:attach()
     screen:add_extra_attr_ids {
       [100] = { special = Screen.colors.Red, undercurl = true },
       [101] = { url = 'https://example.com' },
diff --git a/test/functional/ui/diff_spec.lua b/test/functional/ui/diff_spec.lua
index 8b965e8a97..95159011f1 100644
--- a/test/functional/ui/diff_spec.lua
+++ b/test/functional/ui/diff_spec.lua
@@ -53,7 +53,6 @@ describe('Diff mode screen', function()
     feed('<c-w>w:diffthis<cr><c-w>w')
 
     screen = Screen.new(40, 16)
-    screen:attach()
   end)
 
   it('Add a line in beginning of file 2', function()
@@ -1172,7 +1171,6 @@ end)
 it('win_update redraws lines properly', function()
   local screen
   screen = Screen.new(50, 10)
-  screen:attach()
   screen:set_default_attr_ids({
     [1] = { bold = true, foreground = Screen.colors.Blue1 },
     [2] = { foreground = Screen.colors.Grey100, background = Screen.colors.Red },
@@ -1250,7 +1248,6 @@ end)
 -- oldtest: Test_diff_rnu()
 it('diff updates line numbers below filler lines', function()
   local screen = Screen.new(40, 14)
-  screen:attach()
   exec([[
     call setline(1, ['a', 'a', 'a', 'y', 'b', 'b', 'b', 'b', 'b'])
     vnew
@@ -1310,7 +1307,6 @@ end)
 -- oldtest: Test_diff_with_scroll_and_change()
 it('Align the filler lines when changing text in diff mode', function()
   local screen = Screen.new(40, 20)
-  screen:attach()
   exec([[
     call setline(1, range(1, 15))
     vnew
@@ -1376,7 +1372,6 @@ end)
 
 it("diff mode doesn't restore invalid 'foldcolumn' value #21647", function()
   local screen = Screen.new(60, 6)
-  screen:attach()
   eq('0', api.nvim_get_option_value('foldcolumn', {}))
   command('diffsplit | bd')
   screen:expect([[
@@ -1389,7 +1384,6 @@ end)
 
 it("'relativenumber' doesn't draw beyond end of window in diff mode #29403", function()
   local screen = Screen.new(60, 12)
-  screen:attach()
   command('set relativenumber')
   feed('10aa<CR><Esc>gg')
   command('vnew')
@@ -1433,7 +1427,6 @@ it('diff mode works properly if file contains NUL bytes vim-patch:8.2.3925', fun
   screen:add_extra_attr_ids {
     [100] = { foreground = Screen.colors.Blue, bold = true, background = Screen.colors.Red },
   }
-  screen:attach()
   exec([[
     call setline(1, ['a', 'b', "c\n", 'd', 'e', 'f', 'g'])
     vnew
@@ -1510,7 +1503,6 @@ end)
 -- oldtest: Test_diff_breakindent_after_filler()
 it("diff mode draws 'breakindent' correctly after filler lines", function()
   local screen = Screen.new(45, 8)
-  screen:attach()
   exec([[
     set laststatus=0 diffopt+=followwrap breakindent breakindentopt=min:0
     call setline(1, ['a', '  ' .. repeat('c', 50)])
@@ -1562,7 +1554,6 @@ it('diff mode overlapped diff blocks will be merged', function()
   ]])
 
   local screen = Screen.new(35, 20)
-  screen:attach()
   command('set winwidth=10 diffopt=filler,internal')
 
   command('args Xdifile1 Xdifile2 | vert all | windo diffthis')
@@ -2058,7 +2049,6 @@ end)
 -- oldtest: Test_diff_topline_noscroll()
 it('diff mode does not scroll with line("w0")', function()
   local screen = Screen.new(45, 20)
-  screen:attach()
   exec([[
     set scrolloff=5
     call setline(1, range(1,60))
diff --git a/test/functional/ui/embed_spec.lua b/test/functional/ui/embed_spec.lua
index f525b23f7d..977141ae3e 100644
--- a/test/functional/ui/embed_spec.lua
+++ b/test/functional/ui/embed_spec.lua
@@ -25,8 +25,7 @@ local function test_embed(ext_linegrid)
     clear { args_rm = { '--headless' }, args = { ... } }
 
     -- attach immediately after startup, for early UI
-    screen = Screen.new(60, 8)
-    screen:attach { ext_linegrid = ext_linegrid }
+    screen = Screen.new(60, 8, { ext_linegrid = ext_linegrid })
     screen:add_extra_attr_ids {
       [100] = { foreground = Screen.colors.NvimDarkCyan },
       [101] = { foreground = Screen.colors.NvimDarkRed },
@@ -110,9 +109,10 @@ describe('--embed UI', function()
     clear { args_rm = { '--headless' }, io_extra = pipe.read, env = { NVIM_LOG_FILE = testlog } }
 
     -- attach immediately after startup, for early UI
-    local screen = Screen.new(40, 8)
+    -- rpc_async: Avoid hanging. #24888
+    local screen = Screen.new(40, 8, { stdin_fd = 3 }, false)
     screen.rpc_async = true -- Avoid hanging. #24888
-    screen:attach { stdin_fd = 3 }
+    screen:attach()
 
     writer:write 'hello nvim\nfrom external input\n'
     writer:shutdown(function()
@@ -164,9 +164,9 @@ describe('--embed UI', function()
     clear { args_rm = { '--headless' }, args = { '-q', '-' }, io_extra = pipe.read }
 
     -- attach immediately after startup, for early UI
-    local screen = Screen.new(60, 8)
+    local screen = Screen.new(60, 8, { stdin_fd = 3 }, false)
     screen.rpc_async = true -- Avoid hanging. #24888
-    screen:attach { stdin_fd = 3 }
+    screen:attach()
 
     writer:write [[Xbadfile.c:4:12: error: expected ';' before '}' token]]
     writer:shutdown(function()
@@ -212,7 +212,6 @@ describe('--embed UI', function()
       -- attach immediately after startup, for early UI
       screen = Screen.new(40, 8)
       screen._handle_default_colors_set = handle_default_colors_set
-      screen:attach()
     end
 
     startup()
@@ -239,7 +238,6 @@ describe('--embed UI', function()
     clear { args_rm = { '--headless' } }
 
     local screen = Screen.new(40, 8)
-    screen:attach()
 
     screen:expect {
       condition = function()
@@ -326,8 +324,7 @@ describe('--embed --listen UI', function()
     ok(var_ok)
     eq({}, var)
 
-    local child_screen = Screen.new(40, 6)
-    child_screen:attach(nil, child_session)
+    local child_screen = Screen.new(40, 6, nil, child_session)
     child_screen:expect {
       grid = [[
       ^                                        |
diff --git a/test/functional/ui/float_spec.lua b/test/functional/ui/float_spec.lua
index b76474fd58..57ef9bcff6 100644
--- a/test/functional/ui/float_spec.lua
+++ b/test/functional/ui/float_spec.lua
@@ -640,8 +640,7 @@ describe('float window', function()
   end)
 
   it('tp_curwin updated if external window is moved into split', function()
-    local screen = Screen.new(20, 7)
-    screen:attach { ext_multigrid = true }
+    local _ = Screen.new(20, 7, { ext_multigrid = true })
 
     command('tabnew')
     local external_win = api.nvim_open_win(0, true, {external = true, width = 5, height = 5})
@@ -658,8 +657,6 @@ describe('float window', function()
     command('tabnext')
     eq(2, fn.tabpagenr())
     neq(external_win, api.nvim_get_current_win())
-
-    screen:detach()
   end)
 
   it('no crash with relative="win" after %bdelete #30569', function()
@@ -1018,8 +1015,7 @@ describe('float window', function()
   local function with_ext_multigrid(multigrid)
     local screen, attrs
     before_each(function()
-      screen = Screen.new(40,7)
-      screen:attach {ext_multigrid=multigrid}
+      screen = Screen.new(40,7, {ext_multigrid=multigrid})
       attrs = {
         [0] = {bold=true, foreground=Screen.colors.Blue},
         [1] = {background = Screen.colors.LightMagenta},
diff --git a/test/functional/ui/fold_spec.lua b/test/functional/ui/fold_spec.lua
index 8f6e8aef7e..aea629df07 100644
--- a/test/functional/ui/fold_spec.lua
+++ b/test/functional/ui/fold_spec.lua
@@ -28,8 +28,7 @@ describe('folded lines', function()
   local function with_ext_multigrid(multigrid)
     local screen
     before_each(function()
-      screen = Screen.new(45, 8)
-      screen:attach({ rgb = true, ext_multigrid = multigrid })
+      screen = Screen.new(45, 8, { rgb = true, ext_multigrid = multigrid })
       screen:set_default_attr_ids({
         [1] = { bold = true, foreground = Screen.colors.Blue1 },
         [2] = { reverse = true },
diff --git a/test/functional/ui/highlight_spec.lua b/test/functional/ui/highlight_spec.lua
index c989418409..0f4696f3d3 100644
--- a/test/functional/ui/highlight_spec.lua
+++ b/test/functional/ui/highlight_spec.lua
@@ -32,7 +32,6 @@ describe('highlight: `:syntax manual`', function()
   before_each(function()
     clear()
     screen = Screen.new(20, 5)
-    screen:attach()
     -- syntax highlight for vimscript's "echo"
   end)
 
@@ -93,7 +92,6 @@ describe('highlight defaults', function()
       [100] = { foreground = Screen.colors.Red, background = Screen.colors.WebGreen },
       [101] = { italic = true },
     }
-    screen:attach()
   end)
 
   it('window status bar', function()
@@ -303,7 +301,6 @@ describe('highlight', function()
 
   it('Visual', function()
     local screen = Screen.new(45, 5)
-    screen:attach()
     insert([[
       line1 foo bar
     abcdefghijklmnopqrs
@@ -428,7 +425,6 @@ describe('highlight', function()
 
   it('cterm=standout gui=standout', function()
     local screen = Screen.new(20, 5)
-    screen:attach()
     screen:add_extra_attr_ids {
       [100] = {
         foreground = Screen.colors.Blue1,
@@ -454,7 +450,6 @@ describe('highlight', function()
 
   it('strikethrough', function()
     local screen = Screen.new(25, 6)
-    screen:attach()
     feed_command('syntax on')
     feed_command('syn keyword TmpKeyword foo')
     feed_command('hi! Awesome cterm=strikethrough gui=strikethrough')
@@ -490,7 +485,6 @@ describe('highlight', function()
         background = Screen.colors.Yellow,
       },
     }
-    screen:attach()
     feed_command('syntax on')
     feed_command('hi! Underlined cterm=underline gui=underline')
     feed_command('syn keyword Underlined foobar')
@@ -532,7 +526,6 @@ describe('highlight', function()
 
   it('guisp (special/undercurl)', function()
     local screen = Screen.new(25, 10)
-    screen:attach()
     feed_command('syntax on')
     feed_command('syn keyword TmpKeyword neovim')
     feed_command('syn keyword TmpKeyword1 special')
@@ -585,7 +578,6 @@ describe('highlight', function()
 
   it("'diff', syntax and extmark #23722", function()
     local screen = Screen.new(25, 10)
-    screen:attach()
     exec([[
       new
       call setline(1, ['', '01234 6789'])
@@ -631,7 +623,6 @@ describe("'listchars' highlight", function()
   before_each(function()
     clear()
     screen = Screen.new(20, 5)
-    screen:attach()
   end)
 
   it("'cursorline' and 'cursorcolumn'", function()
@@ -873,7 +864,6 @@ describe('CursorLine and CursorLineNr highlights', function()
       [100] = { background = Screen.colors.LightRed },
       [101] = { foreground = Screen.colors.SlateBlue, background = Screen.colors.Grey90 },
     }
-    screen:attach()
 
     command('filetype on')
     command('syntax on')
@@ -906,7 +896,6 @@ describe('CursorLine and CursorLineNr highlights', function()
       [102] = { foreground = Screen.colors.Grey0, background = Screen.colors.Grey100 },
       [103] = { foreground = Screen.colors.Yellow1, background = Screen.colors.Grey100 },
     }
-    screen:attach()
 
     feed_command('set wrap cursorline')
     feed_command('set showbreak=>>>')
@@ -957,7 +946,6 @@ describe('CursorLine and CursorLineNr highlights', function()
       [102] = { foreground = Screen.colors.Black, background = Screen.colors.Grey100 },
       [103] = { foreground = Screen.colors.WebGreen, background = Screen.colors.Red },
     }
-    screen:attach()
 
     command('set wrap cursorline cursorlineopt=screenline')
     command('set showbreak=>>>')
@@ -1081,7 +1069,6 @@ describe('CursorLine and CursorLineNr highlights', function()
   -- oldtest: Test_cursorline_screenline_resize()
   it("'cursorlineopt' screenline is updated on window resize", function()
     local screen = Screen.new(75, 8)
-    screen:attach()
     exec([[
       50vnew
       call setline(1, repeat('xyz ', 30))
@@ -1123,7 +1110,6 @@ describe('CursorLine and CursorLineNr highlights', function()
       [100] = { background = Screen.colors.LightRed },
       [101] = { foreground = Screen.colors.SlateBlue, background = Screen.colors.Grey90 },
     }
-    screen:attach()
     command('set cursorline relativenumber')
     command('call setline(1, ["","1","2","3",""])')
     feed('Gy3k')
@@ -1151,7 +1137,6 @@ describe('CursorLine and CursorLineNr highlights', function()
       [100] = { foreground = Screen.colors.SlateBlue, background = Screen.colors.Grey90 },
       [101] = { background = Screen.colors.LightRed },
     }
-    screen:attach()
     command('set cursorline')
     command('call setline(1, repeat(["abc"], 50))')
     feed('V<C-f>zbkkjk')
@@ -1166,7 +1151,6 @@ describe('CursorLine and CursorLineNr highlights', function()
   -- oldtest: Test_cursorline_callback()
   it('is updated if cursor is moved up from timer vim-patch:8.2.4591', function()
     local screen = Screen.new(50, 8)
-    screen:attach()
     exec([[
       call setline(1, ['aaaaa', 'bbbbb', 'ccccc', 'ddddd'])
       set cursorline
@@ -1207,7 +1191,6 @@ describe('CursorLine and CursorLineNr highlights', function()
       [100] = { background = Screen.colors.Plum1, underline = true },
       [101] = { background = Screen.colors.Red1, bold = true, underline = true },
     }
-    screen:attach()
 
     command('hi CursorLine ctermbg=red ctermfg=white guibg=red guifg=white')
     command('set cursorline')
@@ -1267,7 +1250,6 @@ describe('CursorLine and CursorLineNr highlights', function()
     screen:add_extra_attr_ids {
       [100] = { foreground = Screen.colors.Black, bold = true, background = Screen.colors.Grey100 },
     }
-    screen:attach()
 
     command('hi CursorLine guibg=red guifg=white')
     command('hi CursorLineNr guibg=white guifg=black gui=bold')
@@ -1308,7 +1290,6 @@ describe('CursorColumn highlight', function()
     screen:add_extra_attr_ids {
       [100] = { background = Screen.colors.Blue1 },
     }
-    screen:attach()
   end)
 
   it('is updated when pressing "i" on a TAB character', function()
@@ -1435,7 +1416,6 @@ describe('ColorColumn highlight', function()
       [101] = { background = Screen.colors.LightRed },
       [102] = { foreground = Screen.colors.Blue1, bold = true, background = Screen.colors.LightRed },
     }
-    screen:attach()
   end)
 
   -- oldtest: Test_colorcolumn()
@@ -1538,7 +1518,6 @@ describe('MsgSeparator highlight and msgsep fillchar', function()
       [12] = { background = Screen.colors.Gray60, bold = true, foreground = tonumber('0x297d4e') },
       [13] = { background = tonumber('0xff4cff'), bold = true, foreground = tonumber('0xb200ff') },
     })
-    screen:attach()
   end)
 
   it('works', function()
@@ -1653,7 +1632,6 @@ describe("'winhighlight' highlight", function()
   before_each(function()
     clear()
     screen = Screen.new(20, 8)
-    screen:attach()
     screen:set_default_attr_ids {
       [0] = { bold = true, foreground = Screen.colors.Blue },
       [1] = { background = Screen.colors.DarkBlue },
@@ -2317,7 +2295,6 @@ describe('highlight namespaces', function()
   before_each(function()
     clear()
     screen = Screen.new(25, 10)
-    screen:attach()
     screen:set_default_attr_ids {
       [1] = { foreground = Screen.colors.Blue, bold = true },
       [2] = { background = Screen.colors.DarkGrey },
@@ -2467,10 +2444,8 @@ describe('highlight namespaces', function()
 end)
 
 describe('synIDattr()', function()
-  local screen
   before_each(function()
     clear()
-    screen = Screen.new(50, 7)
     command('highlight Normal ctermfg=252 guifg=#ff0000 guibg=Black')
     -- Salmon #fa8072 Maroon #800000
     command(
@@ -2495,7 +2470,7 @@ describe('synIDattr()', function()
   end)
 
   it('returns gui-color if RGB-capable UI is attached', function()
-    screen:attach({ rgb = true })
+    local _ = Screen.new(50, 7, { rgb = true })
     eq('#ff0000', eval('synIDattr(hlID("Normal"),  "fg")'))
     eq('Black', eval('synIDattr(hlID("Normal"),  "bg")'))
     eq('Salmon', eval('synIDattr(hlID("Keyword"), "fg")'))
@@ -2503,15 +2478,15 @@ describe('synIDattr()', function()
   end)
 
   it('returns #RRGGBB value for fg#/bg#/sp#', function()
-    screen:attach({ rgb = true })
+    local _ = Screen.new(50, 7, { rgb = true })
     eq('#ff0000', eval('synIDattr(hlID("Normal"),  "fg#")'))
     eq('#000000', eval('synIDattr(hlID("Normal"),  "bg#")'))
     eq('#fa8072', eval('synIDattr(hlID("Keyword"), "fg#")'))
     eq('#800000', eval('synIDattr(hlID("Keyword"), "sp#")'))
   end)
 
-  it('returns color number if non-GUI', function()
-    screen:attach({ rgb = false })
+  it('returns color number if non-RGB GUI', function()
+    local _ = Screen.new(50, 7, { rgb = false })
     eq('252', eval('synIDattr(hlID("Normal"), "fg")'))
     eq('79', eval('synIDattr(hlID("Keyword"), "fg")'))
   end)
@@ -2536,10 +2511,8 @@ describe('synIDattr()', function()
 end)
 
 describe('fg/bg special colors', function()
-  local screen
   before_each(function()
     clear()
-    screen = Screen.new(50, 7)
     command('highlight Normal ctermfg=145 ctermbg=16 guifg=#ff0000 guibg=Black')
     command('highlight Visual ctermfg=bg ctermbg=fg guifg=bg guibg=fg guisp=bg')
   end)
@@ -2558,7 +2531,7 @@ describe('fg/bg special colors', function()
   end)
 
   it('resolve to "Normal" values in RGB-capable UI', function()
-    screen:attach({ rgb = true })
+    local _ = Screen.new(50, 7, { rgb = true })
     eq('bg', eval('synIDattr(hlID("Visual"), "fg")'))
     eq(eval('synIDattr(hlID("Normal"), "bg#")'), eval('synIDattr(hlID("Visual"), "fg#")'))
     eq('fg', eval('synIDattr(hlID("Visual"), "bg")'))
@@ -2568,7 +2541,7 @@ describe('fg/bg special colors', function()
   end)
 
   it('resolve after the "Normal" group is modified', function()
-    screen:attach({ rgb = true })
+    local _ = Screen.new(50, 7, { rgb = true })
     local new_guibg = '#282c34'
     local new_guifg = '#abb2bf'
     command('highlight Normal guifg=' .. new_guifg .. ' guibg=' .. new_guibg)
diff --git a/test/functional/ui/hlstate_spec.lua b/test/functional/ui/hlstate_spec.lua
index 9873ab3103..f8f5ee9488 100644
--- a/test/functional/ui/hlstate_spec.lua
+++ b/test/functional/ui/hlstate_spec.lua
@@ -17,12 +17,7 @@ describe('ext_hlstate detailed highlights', function()
     clear()
     command('syntax on')
     command('hi VertSplit gui=reverse')
-    screen = Screen.new(40, 8)
-    screen:attach({ ext_hlstate = true })
-  end)
-
-  after_each(function()
-    screen:detach()
+    screen = Screen.new(40, 8, { ext_hlstate = true })
   end)
 
   it('work with combined UI and syntax highlights', function()
diff --git a/test/functional/ui/inccommand_spec.lua b/test/functional/ui/inccommand_spec.lua
index c11e009fef..37dc0f5195 100644
--- a/test/functional/ui/inccommand_spec.lua
+++ b/test/functional/ui/inccommand_spec.lua
@@ -66,7 +66,6 @@ local function common_setup(screen, inccommand, text)
     command('syntax on')
     command('set nohlsearch')
     command('hi Substitute guifg=red guibg=yellow')
-    screen:attach()
 
     screen:add_extra_attr_ids {
       [100] = { underline = true },
@@ -556,10 +555,9 @@ describe(":substitute, 'inccommand' preserves undo", function()
   end)
 
   it('with undolevels=1', function()
-    local screen = Screen.new(20, 10)
-
     for _, case in pairs(cases) do
       clear()
+      local screen = Screen.new(20, 10)
       common_setup(screen, case, default_text)
       screen:expect([[
         Inc substitution on |
@@ -617,10 +615,9 @@ describe(":substitute, 'inccommand' preserves undo", function()
   end)
 
   it('with undolevels=2', function()
-    local screen = Screen.new(20, 10)
-
     for _, case in pairs(cases) do
       clear()
+      local screen = Screen.new(20, 10)
       common_setup(screen, case, default_text)
       command('set undolevels=2')
 
@@ -697,10 +694,9 @@ describe(":substitute, 'inccommand' preserves undo", function()
   end)
 
   it('with undolevels=-1', function()
-    local screen = Screen.new(20, 10)
-
     for _, case in pairs(cases) do
       clear()
+      local screen = Screen.new(20, 10)
       common_setup(screen, case, default_text)
 
       command('set undolevels=-1')
@@ -728,6 +724,7 @@ describe(":substitute, 'inccommand' preserves undo", function()
 
       -- repeat with an interrupted substitution
       clear()
+      screen = Screen.new(20, 10)
       common_setup(screen, case, default_text)
 
       command('set undolevels=-1')
@@ -2510,7 +2507,7 @@ describe(':substitute', function()
   end)
 
   it("doesn't prompt to swap cmd range", function()
-    screen = Screen.new(50, 8) -- wide to avoid hit-enter prompt
+    screen:try_resize(50, 8) -- wide to avoid hit-enter prompt
     common_setup(screen, 'split', default_text)
     feed(':2,1s/tw/MO/g')
 
diff --git a/test/functional/ui/inccommand_user_spec.lua b/test/functional/ui/inccommand_user_spec.lua
index e8b546d33a..2d26d2c5e0 100644
--- a/test/functional/ui/inccommand_user_spec.lua
+++ b/test/functional/ui/inccommand_user_spec.lua
@@ -239,7 +239,6 @@ describe("'inccommand' for user commands", function()
   before_each(function()
     clear()
     screen = Screen.new(40, 17)
-    screen:attach()
     exec_lua(setup_replace_cmd)
     command('set cmdwinheight=5')
     insert [[
@@ -549,7 +548,6 @@ describe("'inccommand' with multiple buffers", function()
   before_each(function()
     clear()
     screen = Screen.new(40, 17)
-    screen:attach()
     exec_lua(setup_replace_cmd)
     command('set cmdwinheight=10')
     insert [[
diff --git a/test/functional/ui/input_spec.lua b/test/functional/ui/input_spec.lua
index f377939458..90e0b3e380 100644
--- a/test/functional/ui/input_spec.lua
+++ b/test/functional/ui/input_spec.lua
@@ -282,7 +282,6 @@ end)
 
 it('typing a simplifiable key at hit-enter prompt triggers mapping vim-patch:8.2.0839', function()
   local screen = Screen.new(60, 8)
-  screen:attach()
   command([[nnoremap <C-6> <Cmd>echo 'hit ctrl-6'<CR>]])
   feed_command('ls')
   screen:expect([[
@@ -328,7 +327,6 @@ describe('input non-printable chars', function()
   it("doesn't crash when echoing them back", function()
     write_file('Xtest-overwrite', [[foobar]])
     local screen = Screen.new(60, 8)
-    screen:attach()
     command('set shortmess-=F')
 
     feed_command('e Xtest-overwrite')
@@ -428,7 +426,6 @@ describe('display is updated', function()
   local screen
   before_each(function()
     screen = Screen.new(60, 8)
-    screen:attach()
   end)
 
   it('in Insert mode after <Nop> mapping #17911', function()
diff --git a/test/functional/ui/linematch_spec.lua b/test/functional/ui/linematch_spec.lua
index 03eed5a49c..b564c01eaa 100644
--- a/test/functional/ui/linematch_spec.lua
+++ b/test/functional/ui/linematch_spec.lua
@@ -38,7 +38,6 @@ describe('Diff mode screen with 3 diffs open', function()
     feed(':windo diffthis<cr>')
 
     screen = Screen.new(100, 16)
-    screen:attach()
     feed('<c-w>=')
     feed(':windo set nu!<cr>')
   end)
@@ -217,7 +216,6 @@ describe('Diff mode screen with 2 diffs open', function()
     feed(':windo diffthis<cr>')
 
     screen = Screen.new(100, 20)
-    screen:attach()
     feed('<c-w>=')
     feed(':windo set nu!<cr>')
   end)
@@ -1093,7 +1091,6 @@ describe('regressions', function()
     clear()
     feed(':set diffopt+=linematch:30<cr>')
     screen = Screen.new(100, 20)
-    screen:attach()
     -- line must be greater than MATCH_CHAR_MAX_LEN
     n.api.nvim_buf_set_lines(0, 0, -1, false, { string.rep('a', 1000) .. 'hello' })
     n.exec 'vnew'
@@ -1105,7 +1102,6 @@ describe('regressions', function()
     clear()
     feed(':set diffopt+=linematch:10<cr>')
     screen = Screen.new(100, 20)
-    screen:attach()
     local lines = {}
     for i = 0, 29 do
       lines[#lines + 1] = tostring(i)
diff --git a/test/functional/ui/messages_spec.lua b/test/functional/ui/messages_spec.lua
index 804ba83698..25f3465d46 100644
--- a/test/functional/ui/messages_spec.lua
+++ b/test/functional/ui/messages_spec.lua
@@ -30,8 +30,7 @@ describe('ui/ext_messages', function()
 
   before_each(function()
     clear()
-    screen = Screen.new(25, 5)
-    screen:attach({ rgb = true, ext_messages = true, ext_popupmenu = true })
+    screen = Screen.new(25, 5, { rgb = true, ext_messages = true, ext_popupmenu = true })
     screen:add_extra_attr_ids {
       [100] = { undercurl = true, special = Screen.colors.Red },
     }
@@ -1120,8 +1119,7 @@ describe('ui/builtin messages', function()
   local screen
   before_each(function()
     clear()
-    screen = Screen.new(60, 7)
-    screen:attach({ rgb = true, ext_popupmenu = true })
+    screen = Screen.new(60, 7, { rgb = true, ext_popupmenu = true })
     screen:add_extra_attr_ids {
       [100] = { background = Screen.colors.LightRed },
       [101] = { background = Screen.colors.Grey20 },
@@ -1669,8 +1667,7 @@ describe('ui/ext_messages', function()
 
   before_each(function()
     clear { args_rm = { '--headless' }, args = { '--cmd', 'set shortmess-=I' } }
-    screen = Screen.new(80, 24)
-    screen:attach({ rgb = true, ext_messages = true, ext_popupmenu = true })
+    screen = Screen.new(80, 24, { rgb = true, ext_messages = true, ext_popupmenu = true })
   end)
 
   it('supports intro screen', function()
@@ -1895,8 +1892,7 @@ end)
 
 it('ui/ext_multigrid supports intro screen', function()
   clear { args_rm = { '--headless' }, args = { '--cmd', 'set shortmess-=I' } }
-  local screen = Screen.new(80, 24)
-  screen:attach({ rgb = true, ext_multigrid = true })
+  local screen = Screen.new(80, 24, { rgb = true, ext_multigrid = true })
 
   screen:expect {
     grid = [[
@@ -1971,7 +1967,6 @@ describe('ui/msg_puts_printf', function()
 
     clear({ env = { LANG = 'ja_JP.UTF-8' } })
     screen = Screen.new(25, 5)
-    screen:attach()
 
     if is_os('win') then
       if os.execute('chcp 932 > NUL 2>&1') ~= 0 then
@@ -2012,7 +2007,6 @@ describe('pager', function()
   before_each(function()
     clear()
     screen = Screen.new(35, 8)
-    screen:attach()
     screen:set_default_attr_ids({
       [1] = { bold = true, foreground = Screen.colors.Blue1 },
       [2] = { foreground = Screen.colors.Grey100, background = Screen.colors.Red },
@@ -2808,8 +2802,7 @@ it('pager works in headless mode with UI attached', function()
   end)
 
   local child_session = n.connect(child_server)
-  local child_screen = Screen.new(40, 6)
-  child_screen:attach(nil, child_session)
+  local child_screen = Screen.new(40, 6, nil, child_session)
   child_screen._default_attr_ids = nil -- TODO: unskip with new color scheme
 
   child_session:notify('nvim_command', [[echo range(100)->join("\n")]])
diff --git a/test/functional/ui/mode_spec.lua b/test/functional/ui/mode_spec.lua
index f623cfda06..8c6a284cd6 100644
--- a/test/functional/ui/mode_spec.lua
+++ b/test/functional/ui/mode_spec.lua
@@ -11,8 +11,7 @@ describe('ui mode_change event', function()
 
   before_each(function()
     clear()
-    screen = Screen.new(25, 4)
-    screen:attach({ rgb = true })
+    screen = Screen.new(25, 4, { rgb = true })
   end)
 
   it('works in normal mode', function()
diff --git a/test/functional/ui/mouse_spec.lua b/test/functional/ui/mouse_spec.lua
index 3f071ffd6a..3ee4d429c7 100644
--- a/test/functional/ui/mouse_spec.lua
+++ b/test/functional/ui/mouse_spec.lua
@@ -21,7 +21,6 @@ describe('ui/mouse/input', function()
     command('set listchars=eol:$')
     command('setl listchars=nbsp:x')
     screen = Screen.new(25, 5)
-    screen:attach()
     screen:add_extra_attr_ids {
       [100] = {
         bold = true,
diff --git a/test/functional/ui/multibyte_spec.lua b/test/functional/ui/multibyte_spec.lua
index 3728ec8dbc..001d3cb430 100644
--- a/test/functional/ui/multibyte_spec.lua
+++ b/test/functional/ui/multibyte_spec.lua
@@ -16,8 +16,7 @@ describe('multibyte rendering', function()
   local screen
   before_each(function()
     clear()
-    screen = Screen.new(60, 6)
-    screen:attach({ rgb = true })
+    screen = Screen.new(60, 6, { rgb = true })
   end)
 
   it('works with composed char at start of line', function()
@@ -384,7 +383,6 @@ describe('multibyte rendering: statusline', function()
   before_each(function()
     clear()
     screen = Screen.new(40, 4)
-    screen:attach()
     command('set laststatus=2')
   end)
 
diff --git a/test/functional/ui/multigrid_spec.lua b/test/functional/ui/multigrid_spec.lua
index e009ed0a29..3afda0c4af 100644
--- a/test/functional/ui/multigrid_spec.lua
+++ b/test/functional/ui/multigrid_spec.lua
@@ -16,8 +16,7 @@ describe('ext_multigrid', function()
 
   before_each(function()
     clear{args_rm={'--headless'}, args={'--cmd', 'set laststatus=2'}}
-    screen = Screen.new(53,14)
-    screen:attach({ext_multigrid=true})
+    screen = Screen.new(53,14, {ext_multigrid=true})
     screen:set_default_attr_ids({
       [1] = {bold = true, foreground = Screen.colors.Blue1},
       [2] = {foreground = Screen.colors.Magenta},
diff --git a/test/functional/ui/options_spec.lua b/test/functional/ui/options_spec.lua
index b40ff29dec..211fc1dc77 100644
--- a/test/functional/ui/options_spec.lua
+++ b/test/functional/ui/options_spec.lua
@@ -44,8 +44,7 @@ describe('UI receives option updates', function()
     clear_opts.args_rm = clear_opts.args_rm or {}
     table.insert(clear_opts.args_rm or {}, '--cmd')
     clear(clear_opts)
-    screen = Screen.new(20, 5)
-    screen:attach(screen_opts)
+    screen = Screen.new(20, 5, screen_opts)
     -- NB: UI test suite can be run in both "linegrid" and legacy grid mode.
     -- In both cases check that the received value is the one requested.
     defaults.ext_linegrid = screen._options.ext_linegrid or false
@@ -70,7 +69,6 @@ describe('UI receives option updates', function()
     function screen:_handle_mouse_off()
       table.insert(evs, 'mouse_off')
     end
-    screen:attach()
     screen:expect(function()
       eq({ 'mouse_on' }, evs)
     end)
@@ -215,24 +213,22 @@ describe('UI receives option updates', function()
 end)
 
 describe('UI can set terminal option', function()
-  local screen
   before_each(function()
     -- by default we implicitly "--cmd 'set bg=light'" which ruins everything
     clear { args_rm = { '--cmd' } }
-    screen = Screen.new(20, 5)
   end)
 
   it('term_name', function()
     eq('nvim', eval '&term')
 
-    screen:attach { term_name = 'xterm' }
+    local _ = Screen.new(20, 5, { term_name = 'xterm' })
     eq('xterm', eval '&term')
   end)
 
   it('term_colors', function()
     eq('256', eval '&t_Co')
 
-    screen:attach { term_colors = 8 }
+    local _ = Screen.new(20, 5, { term_colors = 8 })
     eq('8', eval '&t_Co')
   end)
 end)
diff --git a/test/functional/ui/output_spec.lua b/test/functional/ui/output_spec.lua
index 220af06f53..b5a09d814c 100644
--- a/test/functional/ui/output_spec.lua
+++ b/test/functional/ui/output_spec.lua
@@ -109,7 +109,6 @@ describe('shell command :!', function()
   it('handles control codes', function()
     skip(is_os('win'), 'missing printf')
     local screen = Screen.new(50, 4)
-    screen:attach()
     -- Print TAB chars. #2958
     feed([[:!printf '1\t2\t3'<CR>]])
     screen:expect {
@@ -167,7 +166,6 @@ describe('shell command :!', function()
       write_file('bang_filter_spec/f2', 'f2')
       write_file('bang_filter_spec/f3', 'f3')
       screen = Screen.new(53, 10)
-      screen:attach()
     end)
 
     after_each(function()
@@ -241,7 +239,6 @@ describe('shell command :!', function()
     it('powershell supports literal strings', function()
       set_shell_powershell()
       local screen = Screen.new(45, 4)
-      screen:attach()
       feed_command([[!'Write-Output $a']])
       screen:expect([[
         :!'Write-Output $a'                          |
diff --git a/test/functional/ui/popupmenu_spec.lua b/test/functional/ui/popupmenu_spec.lua
index 2f7ff80f02..8fe8975b4a 100644
--- a/test/functional/ui/popupmenu_spec.lua
+++ b/test/functional/ui/popupmenu_spec.lua
@@ -19,8 +19,7 @@ describe('ui/ext_popupmenu', function()
   local screen
   before_each(function()
     clear()
-    screen = Screen.new(60, 8)
-    screen:attach({ rgb = true, ext_popupmenu = true })
+    screen = Screen.new(60, 8, { rgb = true, ext_popupmenu = true })
     source([[
       function! TestComplete() abort
         call complete(1, [{'word':'foo', 'abbr':'fo', 'menu':'the foo', 'info':'foo-y', 'kind':'x'}, 'bar', 'spam'])
@@ -957,7 +956,6 @@ describe("builtin popupmenu 'pumblend'", function()
       [44] = { foreground = tonumber('0x3f3f3f'), background = tonumber('0x7f5d7f') },
       [45] = { background = Screen.colors.WebGray, blend = 0 },
     })
-    screen:attach()
     command('syntax on')
     command('set mouse=a')
     command('set pumblend=10')
@@ -1107,7 +1105,7 @@ describe("builtin popupmenu 'pumblend'", function()
   end)
 
   it('256-color (non-RGB)', function()
-    local screen = Screen.new(60, 8)
+    local screen = Screen.new(60, 8, { rgb = false })
     screen:set_default_attr_ids({
       [1] = { foreground = Screen.colors.Grey0, background = tonumber('0x000007') },
       [2] = { foreground = tonumber('0x000055'), background = tonumber('0x000007') },
@@ -1120,7 +1118,6 @@ describe("builtin popupmenu 'pumblend'", function()
       [9] = { bold = true },
       [10] = { foreground = tonumber('0x000002') },
     })
-    screen:attach({ rgb = false })
     command('set pumblend=10')
     insert([[
       Lorem ipsum dolor sit amet, consectetur
@@ -1149,7 +1146,7 @@ describe('builtin popupmenu', function()
   local function with_ext_multigrid(multigrid)
     local screen
     before_each(function()
-      screen = Screen.new(32, 20)
+      screen = Screen.new(32, 20, { ext_multigrid = multigrid })
       screen:set_default_attr_ids({
         -- popup selected item / scrollbar track
         s = { background = Screen.colors.Grey },
@@ -1194,7 +1191,6 @@ describe('builtin popupmenu', function()
           underline = true,
         },
       })
-      screen:attach({ ext_multigrid = multigrid })
     end)
 
     it('with preview-window above', function()
diff --git a/test/functional/ui/quickfix_spec.lua b/test/functional/ui/quickfix_spec.lua
index 73923a153a..3750ce3d3f 100644
--- a/test/functional/ui/quickfix_spec.lua
+++ b/test/functional/ui/quickfix_spec.lua
@@ -11,7 +11,6 @@ describe('quickfix selection highlight', function()
     clear()
 
     screen = Screen.new(25, 10)
-    screen:attach()
     screen:set_default_attr_ids({
       [1] = { bold = true, foreground = Screen.colors.Blue },
       [2] = { reverse = true },
diff --git a/test/functional/ui/screen.lua b/test/functional/ui/screen.lua
index 358e54dc55..8e15e6c35f 100644
--- a/test/functional/ui/screen.lua
+++ b/test/functional/ui/screen.lua
@@ -6,23 +6,15 @@
 --
 -- Example usage:
 --
+--     -- Attach a screen to the current Nvim instance.
 --     local screen = Screen.new(25, 10)
---     -- Attach the screen to the current Nvim instance.
---     screen:attach()
 --     -- Enter insert-mode and type some text.
 --     feed('ihello screen')
 --     -- Assert the expected screen state.
 --     screen:expect([[
---       hello screen             |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       -- INSERT --             |
+--       hello screen^             |
+--       {1:~                        }|*8
+--       {5:-- INSERT --}             |
 --     ]]) -- <- Last line is stripped
 --
 -- Since screen updates are received asynchronously, expect() actually specifies
@@ -36,36 +28,19 @@
 --    * If the timeout expires, the last match error will be reported and the
 --      test will fail.
 --
--- Continuing the above example, say we want to assert that "-- INSERT --" is
--- highlighted with the bold attribute. The expect() call should look like this:
---
---     NonText = Screen.colors.Blue
---     screen:expect([[
---       hello screen             |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       ~                        |
---       {b:-- INSERT --}             |
---     ]], {b = {bold = true}}, {{bold = true, foreground = NonText}})
---
--- In this case "b" is a string associated with the set composed of one
--- attribute: bold. Note that since the {b:} markup is not a real part of the
+-- The 30 most common highlight groups are predefined, see init_colors() below.
+-- In this case "5" is a predefined highlight associated with the set composed of one
+-- attribute: bold. Note that since the {5:} markup is not a real part of the
 -- screen, the delimiter "|" moved to the right. Also, the highlighting of the
--- NonText markers "~" is ignored in this test.
+-- NonText markers "~" is visible.
 --
--- Tests will often share a group of attribute sets to expect(). Those can be
+-- Tests will often share a group of extra attribute sets to expect(). Those can be
 -- defined at the beginning of a test:
 --
---    NonText = Screen.colors.Blue
---    screen:set_default_attr_ids( {
---      [1] = {reverse = true, bold = true},
---      [2] = {reverse = true}
---    })
+--    screen:add_extra_attr_ids {
+--      [100] = { background = Screen.colors.Plum1, underline = true },
+--      [101] = { background = Screen.colors.Red1, bold = true, underline = true },
+--    }
 --
 -- To help write screen tests, see Screen:snapshot_util().
 -- To debug screen tests, see Screen:redraw_debug().
@@ -180,14 +155,30 @@ local function _init_colors()
   }
 end
 
+--- @class test.functional.ui.screen.Opts
+--- @field ext_linegrid? boolean
+--- @field ext_multigrid? boolean
+--- @field ext_newgrid? boolean
+--- @field ext_popupmenu? boolean
+--- @field ext_wildmenu? boolean
+--- @field rgb? boolean
+--- @field _debug_float? boolean
+
 --- @param width? integer
 --- @param height? integer
+--- @param options? test.functional.ui.screen.Opts
+--- @param session? test.Session|false
 --- @return test.functional.ui.screen
-function Screen.new(width, height)
+function Screen.new(width, height, options, session)
   if not Screen.colors then
     _init_colors()
   end
 
+  options = options or {}
+  if options.ext_linegrid == nil then
+    options.ext_linegrid = true
+  end
+
   local self = setmetatable({
     timeout = default_screen_timeout,
     title = '',
@@ -227,6 +218,7 @@ function Screen.new(width, height)
     _new_attrs = false,
     _width = width or 53,
     _height = height or 14,
+    _options = options,
     _grids = {},
     _grid_win_extmarks = {},
     _cursor = {
@@ -250,6 +242,11 @@ function Screen.new(width, height)
 
   self.uimeths = create_callindex(ui)
 
+  -- session is often nil, which implies the default session
+  if session ~= false then
+    self:attach(session)
+  end
+
   return self
 end
 
@@ -277,20 +274,10 @@ function Screen:set_rgb_cterm(val)
   self._rgb_cterm = val
 end
 
---- @class test.functional.ui.screen.Opts
---- @field ext_linegrid? boolean
---- @field ext_multigrid? boolean
---- @field ext_newgrid? boolean
---- @field ext_popupmenu? boolean
---- @field ext_wildmenu? boolean
---- @field rgb? boolean
---- @field _debug_float? boolean
-
---- @param options? test.functional.ui.screen.Opts
 --- @param session? test.Session
-function Screen:attach(options, session)
+function Screen:attach(session)
   session = session or get_session()
-  options = options or {}
+  local options = self._options
 
   if options.ext_linegrid == nil then
     options.ext_linegrid = true
diff --git a/test/functional/ui/screen_basic_spec.lua b/test/functional/ui/screen_basic_spec.lua
index 85a653df36..f39e9ecc33 100644
--- a/test/functional/ui/screen_basic_spec.lua
+++ b/test/functional/ui/screen_basic_spec.lua
@@ -29,7 +29,6 @@ describe('screen', function()
     local screen_nvim = spawn(nvim_argv)
     set_session(screen_nvim)
     screen = Screen.new()
-    screen:attach()
   end)
 
   it('default initial screen', function()
@@ -47,8 +46,7 @@ local function screen_tests(linegrid)
 
   before_each(function()
     clear()
-    screen = Screen.new()
-    screen:attach({ rgb = true, ext_linegrid = linegrid })
+    screen = Screen.new(53, 14, { rgb = true, ext_linegrid = linegrid })
     screen:set_default_attr_ids({
       [0] = { bold = true, foreground = 255 },
       [1] = { bold = true, reverse = true },
@@ -717,8 +715,7 @@ describe('Screen default colors', function()
     }
     local screen_nvim = spawn(nvim_argv)
     set_session(screen_nvim)
-    screen = Screen.new()
-    screen:attach(termcolors and { rgb = true, ext_termcolors = true } or { rgb = true })
+    screen = Screen.new(53, 14, { rgb = true, ext_termcolors = termcolors or nil })
   end
 
   it('are dark per default', function()
@@ -777,7 +774,6 @@ end)
 it('CTRL-F or CTRL-B scrolls a page after UI attach/resize #20605', function()
   clear()
   local screen = Screen.new(100, 100)
-  screen:attach()
   eq(100, api.nvim_get_option_value('lines', {}))
   eq(99, api.nvim_get_option_value('window', {}))
   eq(99, api.nvim_win_get_height(0))
@@ -810,7 +806,6 @@ end)
 it("showcmd doesn't cause empty grid_line with redrawdebug=compositor #22593", function()
   clear()
   local screen = Screen.new(30, 2)
-  screen:attach()
   command('set showcmd redrawdebug=compositor')
   feed('d')
   screen:expect {
@@ -824,7 +819,6 @@ end)
 it("scrolling in narrow window doesn't draw over separator #29033", function()
   clear()
   local screen = Screen.new(60, 8)
-  screen:attach()
   feed('100Oa<Esc>gg')
   exec([[
     set number nowrap
diff --git a/test/functional/ui/scrollbind_spec.lua b/test/functional/ui/scrollbind_spec.lua
index 9e70b25efa..84316762e4 100644
--- a/test/functional/ui/scrollbind_spec.lua
+++ b/test/functional/ui/scrollbind_spec.lua
@@ -10,7 +10,6 @@ describe('Scrollbind', function()
 
   before_each(function()
     screen = Screen.new(40, 12)
-    screen:attach()
   end)
 
   it('works with one buffer with virtual lines', function()
diff --git a/test/functional/ui/searchhl_spec.lua b/test/functional/ui/searchhl_spec.lua
index eab265cbb1..86490b4527 100644
--- a/test/functional/ui/searchhl_spec.lua
+++ b/test/functional/ui/searchhl_spec.lua
@@ -16,7 +16,6 @@ describe('search highlighting', function()
   before_each(function()
     clear()
     screen = Screen.new(40, 7)
-    screen:attach()
     screen:set_default_attr_ids({
       [1] = { bold = true, foreground = Screen.colors.Blue },
       [2] = { background = Screen.colors.Yellow }, -- Search
diff --git a/test/functional/ui/sign_spec.lua b/test/functional/ui/sign_spec.lua
index da61b6d30f..7874c04c39 100644
--- a/test/functional/ui/sign_spec.lua
+++ b/test/functional/ui/sign_spec.lua
@@ -12,7 +12,6 @@ describe('Signs', function()
   before_each(function()
     clear()
     screen = Screen.new()
-    screen:attach()
     screen:add_extra_attr_ids {
       [100] = { bold = true, foreground = Screen.colors.Magenta1 },
     }
diff --git a/test/functional/ui/spell_spec.lua b/test/functional/ui/spell_spec.lua
index c3e01e5b6a..86d5a362e5 100644
--- a/test/functional/ui/spell_spec.lua
+++ b/test/functional/ui/spell_spec.lua
@@ -17,7 +17,6 @@ describe("'spell'", function()
   before_each(function()
     clear()
     screen = Screen.new(80, 8)
-    screen:attach()
     screen:set_default_attr_ids({
       [0] = { bold = true, foreground = Screen.colors.Blue },
       [1] = { special = Screen.colors.Red, undercurl = true },
diff --git a/test/functional/ui/statuscolumn_spec.lua b/test/functional/ui/statuscolumn_spec.lua
index b225fa518d..268e7173e6 100644
--- a/test/functional/ui/statuscolumn_spec.lua
+++ b/test/functional/ui/statuscolumn_spec.lua
@@ -20,7 +20,6 @@ describe('statuscolumn', function()
   before_each(function()
     clear('--cmd', 'set number nuw=1 | call setline(1, repeat(["aaaaa"], 16)) | norm GM')
     screen = Screen.new()
-    screen:attach()
     exec_lua('ns = vim.api.nvim_create_namespace("")')
   end)
 
diff --git a/test/functional/ui/statusline_spec.lua b/test/functional/ui/statusline_spec.lua
index d628d7b1d7..1d0f181244 100644
--- a/test/functional/ui/statusline_spec.lua
+++ b/test/functional/ui/statusline_spec.lua
@@ -27,7 +27,6 @@ for _, model in ipairs(mousemodels) do
       screen:add_extra_attr_ids {
         [100] = { bold = true, reverse = true, foreground = Screen.colors.Blue },
       }
-      screen:attach()
       command('set laststatus=2 mousemodel=' .. model)
       exec([=[
         function! MyClickFunc(minwid, clicks, button, mods)
@@ -254,7 +253,6 @@ describe('global statusline', function()
   before_each(function()
     clear()
     screen = Screen.new(60, 16)
-    screen:attach()
     screen:add_extra_attr_ids {
       [100] = { foreground = Screen.colors.Magenta1, bold = true },
     }
@@ -520,7 +518,6 @@ end)
 it('statusline is redrawn with :resize from <Cmd> mapping #19629', function()
   clear()
   local screen = Screen.new(40, 8)
-  screen:attach()
   exec([[
     set laststatus=2
     nnoremap <Up> <cmd>resize -1<CR>
@@ -545,7 +542,6 @@ end)
 it('showcmdloc=statusline does not show if statusline is too narrow', function()
   clear()
   local screen = Screen.new(40, 8)
-  screen:attach()
   command('set showcmd')
   command('set showcmdloc=statusline')
   command('1vsplit')
@@ -561,8 +557,7 @@ end)
 
 it('K_EVENT does not trigger a statusline redraw unnecessarily', function()
   clear()
-  local screen = Screen.new(40, 8)
-  screen:attach()
+  local _ = Screen.new(40, 8)
   -- does not redraw on vim.schedule (#17937)
   command([[
     set laststatus=2
@@ -594,7 +589,6 @@ end)
 it('statusline is redrawn on various state changes', function()
   clear()
   local screen = Screen.new(40, 4)
-  screen:attach()
 
   -- recording state change #22683
   command('set ls=2 stl=%{repeat(reg_recording(),5)}')
@@ -660,7 +654,6 @@ end)
 it('ruler is redrawn in cmdline with redrawstatus #22804', function()
   clear()
   local screen = Screen.new(40, 2)
-  screen:attach()
   command([[
     let g:n = 'initial value'
     set ls=1 ru ruf=%{g:n}
@@ -677,7 +670,6 @@ end)
 it('shows correct ruler in cmdline with no statusline', function()
   clear()
   local screen = Screen.new(30, 8)
-  screen:attach()
   -- Use long ruler to check 'ruler' with 'rulerformat' set has correct width.
   command [[
     set ruler rulerformat=%{winnr()}longlonglong ls=0 winwidth=10
@@ -725,7 +717,6 @@ end)
 it('uses "stl" and "stlnc" fillchars even if they are the same #19803', function()
   clear()
   local screen = Screen.new(53, 4)
-  screen:attach()
   command('hi clear StatusLine')
   command('hi clear StatusLineNC')
   command('vsplit')
@@ -742,7 +733,6 @@ end)
 it('showcmdloc=statusline works with vertical splits', function()
   clear()
   local screen = Screen.new(53, 4)
-  screen:attach()
   command('rightbelow vsplit')
   command('set showcmd showcmdloc=statusline')
   feed('1234')
@@ -766,7 +756,6 @@ end)
 it('keymap is shown with vertical splits #27269', function()
   clear()
   local screen = Screen.new(53, 4)
-  screen:attach()
   command('setlocal keymap=dvorak')
   command('rightbelow vsplit')
   screen:expect([[
diff --git a/test/functional/ui/syntax_conceal_spec.lua b/test/functional/ui/syntax_conceal_spec.lua
index be35e9bf4f..57d76e54df 100644
--- a/test/functional/ui/syntax_conceal_spec.lua
+++ b/test/functional/ui/syntax_conceal_spec.lua
@@ -14,7 +14,6 @@ describe('Screen', function()
   before_each(function()
     clear()
     screen = Screen.new(nil, 10)
-    screen:attach()
     screen:set_default_attr_ids({
       [0] = { bold = true, foreground = Screen.colors.Blue },
       [1] = { foreground = Screen.colors.LightGrey, background = Screen.colors.DarkGray },
diff --git a/test/functional/ui/tabline_spec.lua b/test/functional/ui/tabline_spec.lua
index de1e701101..4c6fd8fbda 100644
--- a/test/functional/ui/tabline_spec.lua
+++ b/test/functional/ui/tabline_spec.lua
@@ -13,8 +13,7 @@ describe('ui/ext_tabline', function()
 
   before_each(function()
     clear()
-    screen = Screen.new(25, 5)
-    screen:attach({ rgb = true, ext_tabline = true })
+    screen = Screen.new(25, 5, { rgb = true, ext_tabline = true })
     function screen:_handle_tabline_update(curtab, tabs, curbuf, buffers)
       event_curtab = curtab
       event_tabs = tabs
@@ -100,7 +99,6 @@ describe('tabline', function()
   before_each(function()
     clear()
     screen = Screen.new(42, 5)
-    screen:attach()
   end)
 
   it('redraws when tabline option is set', function()
diff --git a/test/functional/ui/title_spec.lua b/test/functional/ui/title_spec.lua
index 3189232957..66eb15478b 100644
--- a/test/functional/ui/title_spec.lua
+++ b/test/functional/ui/title_spec.lua
@@ -18,7 +18,6 @@ describe('title', function()
   before_each(function()
     clear()
     screen = Screen.new()
-    screen:attach()
   end)
 
   it('has correct default title with unnamed file', function()
diff --git a/test/functional/ui/wildmode_spec.lua b/test/functional/ui/wildmode_spec.lua
index 4d01b7a779..94710bfb74 100644
--- a/test/functional/ui/wildmode_spec.lua
+++ b/test/functional/ui/wildmode_spec.lua
@@ -19,7 +19,6 @@ describe("'wildmenu'", function()
     screen:add_extra_attr_ids {
       [100] = { background = Screen.colors.Yellow1, foreground = Screen.colors.Black },
     }
-    screen:attach()
   end)
 
   -- oldtest: Test_wildmenu_screendump()
@@ -492,7 +491,6 @@ describe('command line completion', function()
     screen:add_extra_attr_ids {
       [100] = { background = Screen.colors.Yellow1, foreground = Screen.colors.Black },
     }
-    screen:attach()
   end)
   after_each(function()
     os.remove('Xtest-functional-viml-compl-dir')
@@ -592,8 +590,7 @@ describe('ui/ext_wildmenu', function()
 
   before_each(function()
     clear()
-    screen = Screen.new(25, 5)
-    screen:attach({ rgb = true, ext_wildmenu = true })
+    screen = Screen.new(25, 5, { rgb = true, ext_wildmenu = true })
   end)
 
   it('works with :sign <tab>', function()
diff --git a/test/functional/ui/winbar_spec.lua b/test/functional/ui/winbar_spec.lua
index bbdf3ad9ba..d1fd273dc1 100644
--- a/test/functional/ui/winbar_spec.lua
+++ b/test/functional/ui/winbar_spec.lua
@@ -18,7 +18,6 @@ describe('winbar', function()
   before_each(function()
     clear()
     screen = Screen.new(60, 13)
-    screen:attach()
     screen:set_default_attr_ids({
       [1] = { bold = true },
       [2] = { reverse = true },
@@ -548,7 +547,6 @@ describe('local winbar with tabs', function()
   before_each(function()
     clear()
     screen = Screen.new(60, 10)
-    screen:attach()
     api.nvim_set_option_value('winbar', 'foo', { scope = 'local', win = 0 })
   end)
 
@@ -626,7 +624,6 @@ it('winbar works properly when redrawing is postponed #23534', function()
     },
   })
   local screen = Screen.new(60, 6)
-  screen:attach()
   screen:expect([[
     {5:(winbar)                                                    }|
     ^                                                            |