test: simplify platform detection (#21020)

Extend the capabilities of is_os to detect more platforms such as
freebsd and openbsd. Also remove `iswin()` helper function as it can be
replaced by `is_os("win")`.

12 files changed, 70 insertions, 73 deletions

diff --git a/test/functional/terminal/altscreen_spec.lua b/test/functional/terminal/altscreen_spec.lua
index 457a5aa18f..cbe5e06005 100644
--- a/test/functional/terminal/altscreen_spec.lua
+++ b/test/functional/terminal/altscreen_spec.lua
@@ -6,7 +6,7 @@ local feed_data = thelpers.feed_data
 local enter_altscreen = thelpers.enter_altscreen
 local exit_altscreen = thelpers.exit_altscreen
 
-if helpers.skip(helpers.iswin()) then return end
+if helpers.skip(helpers.is_os('win')) then return end
 
 describe(':terminal altscreen', function()
   local screen
diff --git a/test/functional/terminal/api_spec.lua b/test/functional/terminal/api_spec.lua
index b5697c4c6b..38ef7c2a61 100644
--- a/test/functional/terminal/api_spec.lua
+++ b/test/functional/terminal/api_spec.lua
@@ -2,7 +2,7 @@ local helpers = require('test.functional.helpers')(after_each)
 local child_session = require('test.functional.terminal.helpers')
 local ok = helpers.ok
 
-if helpers.skip(helpers.iswin()) then return end
+if helpers.skip(helpers.is_os('win')) then return end
 
 describe('api', function()
   local screen
diff --git a/test/functional/terminal/buffer_spec.lua b/test/functional/terminal/buffer_spec.lua
index 5a75af69c0..9c8b983ff7 100644
--- a/test/functional/terminal/buffer_spec.lua
+++ b/test/functional/terminal/buffer_spec.lua
@@ -15,7 +15,7 @@ local matches = helpers.matches
 local exec_lua = helpers.exec_lua
 local sleep = helpers.sleep
 local funcs = helpers.funcs
-local iswin = helpers.iswin
+local is_os = helpers.is_os
 local skip = helpers.skip
 
 describe(':terminal buffer', function()
@@ -202,7 +202,7 @@ describe(':terminal buffer', function()
 
     -- Save the buffer number of the terminal for later testing.
     local tbuf = eval('bufnr("%")')
-    local exitcmd = helpers.iswin()
+    local exitcmd = helpers.is_os('win')
       and "['cmd', '/c', 'exit']"
       or "['sh', '-c', 'exit']"
     source([[
@@ -264,7 +264,7 @@ describe(':terminal buffer', function()
   end)
 
   it('it works with set rightleft #11438', function()
-    skip(iswin())
+    skip(is_os('win'))
     local columns = eval('&columns')
     feed(string.rep('a', columns))
     command('set rightleft')
diff --git a/test/functional/terminal/cursor_spec.lua b/test/functional/terminal/cursor_spec.lua
index fdd7b9407b..98ac03211a 100644
--- a/test/functional/terminal/cursor_spec.lua
+++ b/test/functional/terminal/cursor_spec.lua
@@ -9,7 +9,7 @@ local matches = helpers.matches
 local feed_command = helpers.feed_command
 local hide_cursor = thelpers.hide_cursor
 local show_cursor = thelpers.show_cursor
-local iswin = helpers.iswin
+local is_os = helpers.is_os
 local skip = helpers.skip
 
 describe(':terminal cursor', function()
@@ -90,7 +90,7 @@ describe(':terminal cursor', function()
 
   describe('when invisible', function()
     it('is not highlighted and is detached from screen cursor', function()
-      skip(iswin())
+      skip(is_os('win'))
       hide_cursor()
       screen:expect([[
         tty ready                                         |
@@ -363,7 +363,7 @@ describe('buffer cursor position is correct in terminal without number column',
   end)
 
   describe('in a line with single-cell composed multibyte characters and no trailing spaces,', function()
-    if skip(iswin(), "Encoding problem?") then return end
+    if skip(is_os('win'), "Encoding problem?") then return end
 
     before_each(function()
       setup_ex_register('µ̳µ̳µ̳µ̳µ̳µ̳µ̳µ̳')
@@ -446,7 +446,7 @@ describe('buffer cursor position is correct in terminal without number column',
   end)
 
   describe('in a line with double-cell multibyte characters and no trailing spaces,', function()
-    skip(iswin(), "Encoding problem?")
+    skip(is_os('win'), "Encoding problem?")
 
     before_each(function()
       setup_ex_register('哦哦哦哦哦哦哦哦')
@@ -743,7 +743,7 @@ describe('buffer cursor position is correct in terminal with number column', fun
   end)
 
   describe('in a line with single-cell composed multibyte characters and no trailing spaces,', function()
-    if skip(iswin(), "Encoding problem?") then return end
+    if skip(is_os('win'), "Encoding problem?") then return end
 
     before_each(function()
       setup_ex_register('µ̳µ̳µ̳µ̳µ̳µ̳µ̳µ̳')
@@ -826,7 +826,7 @@ describe('buffer cursor position is correct in terminal with number column', fun
   end)
 
   describe('in a line with double-cell multibyte characters and no trailing spaces,', function()
-    skip(iswin(), "Encoding problem?")
+    skip(is_os('win'), "Encoding problem?")
 
     before_each(function()
       setup_ex_register('哦哦哦哦哦哦哦哦')
diff --git a/test/functional/terminal/edit_spec.lua b/test/functional/terminal/edit_spec.lua
index 95ee561d2b..80287bb3d0 100644
--- a/test/functional/terminal/edit_spec.lua
+++ b/test/functional/terminal/edit_spec.lua
@@ -36,7 +36,7 @@ describe(':edit term://*', function()
   end)
 
   it("runs TermOpen early enough to set buffer-local 'scrollback'", function()
-    if helpers.skip(helpers.iswin()) then return end
+    if helpers.skip(helpers.is_os('win')) then return end
     local columns, lines = 20, 4
     local scr = get_screen(columns, lines)
     local rep = 97
diff --git a/test/functional/terminal/ex_terminal_spec.lua b/test/functional/terminal/ex_terminal_spec.lua
index 48254faa31..6b7e93a864 100644
--- a/test/functional/terminal/ex_terminal_spec.lua
+++ b/test/functional/terminal/ex_terminal_spec.lua
@@ -8,10 +8,10 @@ local feed_command, eval = helpers.feed_command, helpers.eval
 local funcs = helpers.funcs
 local retry = helpers.retry
 local ok = helpers.ok
-local iswin = helpers.iswin
 local command = helpers.command
-local isCI = helpers.isCI
 local skip = helpers.skip
+local is_os = helpers.is_os
+local is_ci = helpers.is_ci
 
 describe(':terminal', function()
   local screen
@@ -47,8 +47,8 @@ describe(':terminal', function()
   end)
 
   it("reads output buffer on terminal reporting #4151", function()
-    skip(isCI('cirrus') or iswin())
-    if iswin() then
+    skip(is_ci('cirrus') or is_os('win'))
+    if is_os('win') then
       feed_command([[terminal powershell -NoProfile -NoLogo -Command Write-Host -NoNewline "\"$([char]27)[6n\""; Start-Sleep -Milliseconds 500 ]])
     else
       feed_command([[terminal printf '\e[6n'; sleep 0.5 ]])
@@ -57,7 +57,7 @@ describe(':terminal', function()
   end)
 
   it("in normal-mode :split does not move cursor", function()
-    if iswin() then
+    if is_os('win') then
       feed_command([[terminal for /L \\%I in (1,0,2) do ( echo foo & ping -w 100 -n 1 127.0.0.1 > nul )]])
     else
       feed_command([[terminal while true; do echo foo; sleep .1; done]])
@@ -144,7 +144,7 @@ describe(':terminal (with fake shell)', function()
   end
 
   it('with no argument, acts like termopen()', function()
-    skip(iswin())
+    skip(is_os('win'))
     terminal_with_fake_shell()
     retry(nil, 4 * screen.timeout, function()
     screen:expect([[
@@ -168,7 +168,7 @@ describe(':terminal (with fake shell)', function()
   end)
 
   it("with no argument, but 'shell' has arguments, acts like termopen()", function()
-    skip(iswin())
+    skip(is_os('win'))
     nvim('set_option', 'shell', testprg('shell-test')..' -t jeff')
     terminal_with_fake_shell()
     screen:expect([[
@@ -180,7 +180,7 @@ describe(':terminal (with fake shell)', function()
   end)
 
   it('executes a given command through the shell', function()
-    skip(iswin())
+    skip(is_os('win'))
     command('set shellxquote=')   -- win: avoid extra quotes
     terminal_with_fake_shell('echo hi')
     screen:expect([[
@@ -192,7 +192,7 @@ describe(':terminal (with fake shell)', function()
   end)
 
   it("executes a given command through the shell, when 'shell' has arguments", function()
-    skip(iswin())
+    skip(is_os('win'))
     nvim('set_option', 'shell', testprg('shell-test')..' -t jeff')
     command('set shellxquote=')   -- win: avoid extra quotes
     terminal_with_fake_shell('echo hi')
@@ -205,7 +205,7 @@ describe(':terminal (with fake shell)', function()
   end)
 
   it('allows quotes and slashes', function()
-    skip(iswin())
+    skip(is_os('win'))
     command('set shellxquote=')   -- win: avoid extra quotes
     terminal_with_fake_shell([[echo 'hello' \ "world"]])
     screen:expect([[
@@ -242,7 +242,7 @@ describe(':terminal (with fake shell)', function()
   end)
 
   it('works with :find', function()
-    skip(iswin())
+    skip(is_os('win'))
     terminal_with_fake_shell()
     screen:expect([[
       ^ready $                                           |
@@ -253,7 +253,7 @@ describe(':terminal (with fake shell)', function()
     eq('term://', string.match(eval('bufname("%")'), "^term://"))
     feed([[<C-\><C-N>]])
     feed_command([[find */shadacat.py]])
-    if iswin() then
+    if is_os('win') then
       eq('scripts\\shadacat.py', eval('bufname("%")'))
     else
       eq('scripts/shadacat.py', eval('bufname("%")'))
@@ -261,7 +261,7 @@ describe(':terminal (with fake shell)', function()
   end)
 
   it('works with gf', function()
-    skip(iswin())
+    skip(is_os('win'))
     command('set shellxquote=')   -- win: avoid extra quotes
     terminal_with_fake_shell([[echo "scripts/shadacat.py"]])
     retry(nil, 4 * screen.timeout, function()
diff --git a/test/functional/terminal/highlight_spec.lua b/test/functional/terminal/highlight_spec.lua
index 3e121405d8..2ac45771d4 100644
--- a/test/functional/terminal/highlight_spec.lua
+++ b/test/functional/terminal/highlight_spec.lua
@@ -7,7 +7,7 @@ local nvim_prog_abs = helpers.nvim_prog_abs
 local eq, eval = helpers.eq, helpers.eval
 local funcs = helpers.funcs
 local nvim_set = helpers.nvim_set
-local iswin = helpers.iswin
+local is_os = helpers.is_os
 local skip = helpers.skip
 
 describe(':terminal highlight', function()
@@ -60,7 +60,7 @@ describe(':terminal highlight', function()
       end)
 
       local function pass_attrs()
-        skip(iswin())
+        skip(is_os('win'))
         screen:expect(sub([[
           tty ready                                         |
           {NUM:text}text{10: }                                         |
@@ -75,7 +75,7 @@ describe(':terminal highlight', function()
       it('will pass the corresponding attributes', pass_attrs)
 
       it('will pass the corresponding attributes on scrollback', function()
-        skip(iswin())
+        skip(is_os('win'))
         pass_attrs()
         local lines = {}
         for i = 1, 8 do
@@ -199,7 +199,7 @@ describe(':terminal highlight forwarding', function()
   end)
 
   it('will handle cterm and rgb attributes', function()
-    skip(iswin())
+    skip(is_os('win'))
     thelpers.set_fg(3)
     thelpers.feed_data('text')
     thelpers.feed_termcode('[38:2:255:128:0m')
@@ -251,7 +251,7 @@ describe(':terminal highlight with custom palette', function()
   end)
 
   it('will use the custom color', function()
-    skip(iswin())
+    skip(is_os('win'))
     thelpers.set_fg(3)
     thelpers.feed_data('text')
     thelpers.clear_attrs()
diff --git a/test/functional/terminal/mouse_spec.lua b/test/functional/terminal/mouse_spec.lua
index a062a77a14..899df0ac54 100644
--- a/test/functional/terminal/mouse_spec.lua
+++ b/test/functional/terminal/mouse_spec.lua
@@ -3,7 +3,7 @@ local thelpers = require('test.functional.terminal.helpers')
 local clear, eq, eval = helpers.clear, helpers.eq, helpers.eval
 local feed, nvim, command = helpers.feed, helpers.nvim, helpers.command
 local feed_data = thelpers.feed_data
-local iswin = helpers.iswin
+local is_os = helpers.is_os
 local skip = helpers.skip
 
 describe(':terminal mouse', function()
@@ -68,7 +68,7 @@ describe(':terminal mouse', function()
     end)
 
     it('does not leave terminal mode on left-release', function()
-      skip(iswin())
+      skip(is_os('win'))
       feed('<LeftRelease>')
       eq('t', eval('mode(1)'))
     end)
@@ -89,7 +89,7 @@ describe(':terminal mouse', function()
       end)
 
       it('will forward mouse press, drag and release to the program', function()
-        skip(iswin())
+        skip(is_os('win'))
         feed('<LeftMouse><1,2>')
         screen:expect([[
           line27                                            |
@@ -133,7 +133,7 @@ describe(':terminal mouse', function()
       end)
 
       it('will forward mouse scroll to the program', function()
-        skip(iswin())
+        skip(is_os('win'))
         feed('<ScrollWheelUp><0,0>')
         screen:expect([[
           line27                                            |
@@ -147,7 +147,7 @@ describe(':terminal mouse', function()
       end)
 
       it('dragging and scrolling do not interfere with each other', function()
-        skip(iswin())
+        skip(is_os('win'))
         feed('<LeftMouse><1,2>')
         screen:expect([[
           line27                                            |
@@ -201,7 +201,7 @@ describe(':terminal mouse', function()
       end)
 
       it('will forward mouse clicks to the program with the correct even if set nu', function()
-        skip(iswin())
+        skip(is_os('win'))
         command('set number')
         -- When the display area such as a number is clicked, it returns to the
         -- normal mode.
@@ -232,7 +232,7 @@ describe(':terminal mouse', function()
     end)
 
     describe('with a split window and other buffer', function()
-      skip(iswin())
+      skip(is_os('win'))
       before_each(function()
         feed('<c-\\><c-n>:vsp<cr>')
         screen:expect([[
diff --git a/test/functional/terminal/scrollback_spec.lua b/test/functional/terminal/scrollback_spec.lua
index 873445f281..a4899c8219 100644
--- a/test/functional/terminal/scrollback_spec.lua
+++ b/test/functional/terminal/scrollback_spec.lua
@@ -3,7 +3,6 @@ local helpers = require('test.functional.helpers')(after_each)
 local thelpers = require('test.functional.terminal.helpers')
 local clear, eq, curbuf = helpers.clear, helpers.eq, helpers.curbuf
 local feed, testprg, feed_command = helpers.feed, helpers.testprg, helpers.feed_command
-local iswin = helpers.iswin
 local eval = helpers.eval
 local command = helpers.command
 local matches = helpers.matches
@@ -16,6 +15,7 @@ local pcall_err = helpers.pcall_err
 local exec_lua = helpers.exec_lua
 local assert_alive = helpers.assert_alive
 local skip = helpers.skip
+local is_os = helpers.is_os
 
 describe(':terminal scrollback', function()
   local screen
@@ -140,7 +140,7 @@ describe(':terminal scrollback', function()
 
 
     describe('and height decreased by 1', function()
-      if skip(iswin()) then return end
+      if skip(is_os('win')) then return end
       local function will_hide_top_line()
         feed([[<C-\><C-N>]])
         screen:try_resize(screen._width - 2, screen._height - 1)
@@ -186,7 +186,7 @@ describe(':terminal scrollback', function()
     -- XXX: Can't test this reliably on Windows unless the cursor is _moved_
     --      by the resize. http://docs.libuv.org/en/v1.x/signal.html
     --      See also: https://github.com/rprichard/winpty/issues/110
-    if skip(iswin()) then return end
+    if skip(is_os('win')) then return end
 
     describe('and the height is decreased by 2', function()
       before_each(function()
@@ -265,7 +265,7 @@ describe(':terminal scrollback', function()
       -- XXX: Can't test this reliably on Windows unless the cursor is _moved_
       --      by the resize. http://docs.libuv.org/en/v1.x/signal.html
       --      See also: https://github.com/rprichard/winpty/issues/110
-      if skip(iswin()) then return end
+      if skip(is_os('win')) then return end
       local function pop_then_push()
         screen:try_resize(screen._width, screen._height + 1)
         screen:expect([[
@@ -347,7 +347,7 @@ end)
 
 describe(':terminal prints more lines than the screen height and exits', function()
   it('will push extra lines to scrollback', function()
-    skip(iswin())
+    skip(is_os('win'))
     clear()
     local screen = Screen.new(30, 7)
     screen:attach({rgb=false})
@@ -397,21 +397,21 @@ describe("'scrollback' option", function()
 
   it('set to 0 behaves as 1', function()
     local screen
-    if iswin() then
+    if is_os('win') then
       screen = thelpers.screen_setup(nil, "['cmd.exe']", 30)
     else
       screen = thelpers.screen_setup(nil, "['sh']", 30)
     end
 
     curbufmeths.set_option('scrollback', 0)
-    feed_data(('%s REP 31 line%s'):format(testprg('shell-test'), iswin() and '\r' or '\n'))
+    feed_data(('%s REP 31 line%s'):format(testprg('shell-test'), is_os('win') and '\r' or '\n'))
     screen:expect{any='30: line                      '}
     retry(nil, nil, function() expect_lines(7) end)
   end)
 
   it('deletes lines (only) if necessary', function()
     local screen
-    if iswin() then
+    if is_os('win') then
       command([[let $PROMPT='$$']])
       screen = thelpers.screen_setup(nil, "['cmd.exe']", 30)
     else
@@ -424,7 +424,7 @@ describe("'scrollback' option", function()
     -- Wait for prompt.
     screen:expect{any='%$'}
 
-    feed_data(('%s REP 31 line%s'):format(testprg('shell-test'), iswin() and '\r' or '\n'))
+    feed_data(('%s REP 31 line%s'):format(testprg('shell-test'), is_os('win') and '\r' or '\n'))
     screen:expect{any='30: line                      '}
 
     retry(nil, nil, function() expect_lines(33, 2) end)
@@ -437,8 +437,8 @@ describe("'scrollback' option", function()
     -- 'scrollback' option is synchronized with the internal sb_buffer.
     command('sleep 100m')
 
-    feed_data(('%s REP 41 line%s'):format(testprg('shell-test'), iswin() and '\r' or '\n'))
-    if iswin() then
+    feed_data(('%s REP 41 line%s'):format(testprg('shell-test'), is_os('win') and '\r' or '\n'))
+    if is_os('win') then
       screen:expect{grid=[[
         37: line                      |
         38: line                      |
@@ -462,8 +462,8 @@ describe("'scrollback' option", function()
     expect_lines(58)
 
     -- Verify off-screen state
-    matches((iswin() and '^36: line[ ]*$' or '^35: line[ ]*$'), eval("getline(line('w0') - 1)"))
-    matches((iswin() and '^27: line[ ]*$' or '^26: line[ ]*$'), eval("getline(line('w0') - 10)"))
+    matches((is_os('win') and '^36: line[ ]*$' or '^35: line[ ]*$'), eval("getline(line('w0') - 1)"))
+    matches((is_os('win') and '^27: line[ ]*$' or '^26: line[ ]*$'), eval("getline(line('w0') - 10)"))
   end)
 
   it('deletes extra lines immediately', function()
@@ -607,7 +607,7 @@ describe("pending scrollback line handling", function()
   end)
 
   it("does not crash after nvim_buf_call #14891", function()
-    skip(iswin())
+    skip(is_os('win'))
     exec_lua [[
       local a = vim.api
       local bufnr = a.nvim_create_buf(false, true)
diff --git a/test/functional/terminal/tui_spec.lua b/test/functional/terminal/tui_spec.lua
index 20c677c46c..b3d2625d78 100644
--- a/test/functional/terminal/tui_spec.lua
+++ b/test/functional/terminal/tui_spec.lua
@@ -5,7 +5,6 @@
 -- http://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h2-Bracketed-Paste-Mode
 
 local helpers = require('test.functional.helpers')(after_each)
-local uname = helpers.uname
 local thelpers = require('test.functional.terminal.helpers')
 local Screen = require('test.functional.ui.screen')
 local assert_alive = helpers.assert_alive
@@ -22,9 +21,10 @@ local ok = helpers.ok
 local read_file = helpers.read_file
 local funcs = helpers.funcs
 local meths = helpers.meths
-local isCI = helpers.isCI
+local is_ci = helpers.is_ci
+local is_os = helpers.is_os
 
-if helpers.skip(helpers.iswin()) then return end
+if helpers.skip(helpers.is_os('win')) then return end
 
 describe('TUI', function()
   local screen
@@ -822,7 +822,7 @@ describe('TUI', function()
   end)
 
   it('paste: terminal mode', function()
-    if isCI('github') then
+    if is_ci('github') then
         pending("tty-test complains about not owning the terminal -- actions/runner#241")
     end
     child_exec_lua('vim.o.statusline="^^^^^^^"')
@@ -1089,7 +1089,7 @@ describe('TUI', function()
     -- "bracketed paste"
     feed_data('\027[200~'..expected..'\027[201~')
     -- FIXME: Data race between the two feeds
-    if uname() == 'freebsd' then screen:sleep(1) end
+    if is_os('freebsd') then screen:sleep(1) end
     feed_data(' end')
     expected = expected..' end'
     screen:expect([[
@@ -1329,7 +1329,7 @@ describe('TUI', function()
   end)
 
   it('forwards :term palette colors with termguicolors', function()
-    if isCI('github') then
+    if is_ci('github') then
         pending("tty-test complains about not owning the terminal -- actions/runner#241")
     end
     screen:set_rgb_cterm(true)
@@ -1668,7 +1668,6 @@ end)
 -- does not initialize the TUI.
 describe("TUI 't_Co' (terminal colors)", function()
   local screen
-  local is_freebsd = (uname() == 'freebsd')
 
   local function assert_term_colors(term, colorterm, maxcolors)
     helpers.clear({env={TERM=term}, args={}})
@@ -1771,7 +1770,7 @@ describe("TUI 't_Co' (terminal colors)", function()
   -- which is raised to 16 by COLORTERM.
 
   it("TERM=screen no COLORTERM uses 8/256 colors", function()
-    if is_freebsd then
+    if is_os('freebsd') then
       assert_term_colors("screen", nil, 256)
     else
       assert_term_colors("screen", nil, 8)
@@ -1779,7 +1778,7 @@ describe("TUI 't_Co' (terminal colors)", function()
   end)
 
   it("TERM=screen COLORTERM=screen uses 16/256 colors", function()
-    if is_freebsd then
+    if is_os('freebsd') then
       assert_term_colors("screen", "screen", 256)
     else
       assert_term_colors("screen", "screen", 16)
@@ -1942,8 +1941,6 @@ end)
 -- does not initialize the TUI.
 describe("TUI 'term' option", function()
   local screen
-  local is_bsd = not not string.find(uname(), 'bsd')
-  local is_macos = not not string.find(uname(), 'darwin')
 
   local function assert_term(term_envvar, term_expected)
     clear()
@@ -1969,11 +1966,11 @@ describe("TUI 'term' option", function()
   end)
 
   it('gets system-provided term if $TERM is valid', function()
-    if uname() == "openbsd" then
+    if is_os('openbsd') then
       assert_term("xterm", "xterm")
-    elseif is_bsd then  -- BSD lacks terminfo, builtin is always used.
+    elseif is_os('bsd') then  -- BSD lacks terminfo, builtin is always used.
       assert_term("xterm", "builtin_xterm")
-    elseif is_macos then
+    elseif is_os('mac') then
       local status, _ = pcall(assert_term, "xterm", "xterm")
       if not status then
         pending("macOS: unibilium could not find terminfo")
diff --git a/test/functional/terminal/window_spec.lua b/test/functional/terminal/window_spec.lua
index 81cd1017db..80e9d78400 100644
--- a/test/functional/terminal/window_spec.lua
+++ b/test/functional/terminal/window_spec.lua
@@ -3,12 +3,12 @@ local thelpers = require('test.functional.terminal.helpers')
 local feed_data = thelpers.feed_data
 local feed, clear = helpers.feed, helpers.clear
 local poke_eventloop = helpers.poke_eventloop
-local iswin = helpers.iswin
 local command = helpers.command
 local retry = helpers.retry
 local eq = helpers.eq
 local eval = helpers.eval
 local skip = helpers.skip
+local is_os = helpers.is_os
 
 describe(':terminal window', function()
   local screen
@@ -19,7 +19,7 @@ describe(':terminal window', function()
   end)
 
   it('sets topline correctly #8556', function()
-    skip(iswin())
+    skip(is_os('win'))
     -- Test has hardcoded assumptions of dimensions.
     eq(7, eval('&lines'))
     feed_data('\n\n\n')  -- Add blank lines.
@@ -55,7 +55,7 @@ describe(':terminal window', function()
         {3:-- TERMINAL --}                                    |
       ]])
 
-      skip(iswin(), 'win: :terminal resize is unreliable #7007')
+      skip(is_os('win'), 'win: :terminal resize is unreliable #7007')
 
       -- numberwidth=9
       feed([[<C-\><C-N>]])
@@ -171,7 +171,7 @@ describe(':terminal with multigrid', function()
     ]])
 
     screen:try_resize_grid(2, 20, 10)
-    if iswin() then
+    if is_os('win') then
       screen:expect{any="rows: 10, cols: 20"}
     else
       screen:expect([[
@@ -200,7 +200,7 @@ describe(':terminal with multigrid', function()
     end
 
     screen:try_resize_grid(2, 70, 3)
-    if iswin() then
+    if is_os('win') then
       screen:expect{any="rows: 3, cols: 70"}
     else
       screen:expect([[
@@ -222,7 +222,7 @@ describe(':terminal with multigrid', function()
     end
 
     screen:try_resize_grid(2, 0, 0)
-    if iswin() then
+    if is_os('win') then
       screen:expect{any="rows: 6, cols: 50"}
     else
       screen:expect([[
diff --git a/test/functional/terminal/window_split_tab_spec.lua b/test/functional/terminal/window_split_tab_spec.lua
index b62d173cea..1d77e1e92e 100644
--- a/test/functional/terminal/window_split_tab_spec.lua
+++ b/test/functional/terminal/window_split_tab_spec.lua
@@ -8,9 +8,9 @@ local command = helpers.command
 local eq = helpers.eq
 local eval = helpers.eval
 local meths = helpers.meths
-local iswin = helpers.iswin
 local sleep = helpers.sleep
 local retry = helpers.retry
+local is_os = helpers.is_os
 
 describe(':terminal', function()
   local screen
@@ -96,7 +96,7 @@ describe(':terminal', function()
     local w1, h1 = screen._width - 3, screen._height - 2
     local w2, h2 = w1 - 6, h1 - 3
 
-    if iswin() then
+    if is_os('win') then
       -- win: SIGWINCH is unreliable, use a weaker test. #7506
       retry(3, 30000, function()
         screen:try_resize(w1, h1)