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")`.

1 files changed, 4 insertions, 4 deletions

diff --git a/test/functional/ex_cmds/mksession_spec.lua b/test/functional/ex_cmds/mksession_spec.lua
index b7ff6a7bf7..0a0c7ca410 100644
--- a/test/functional/ex_cmds/mksession_spec.lua
+++ b/test/functional/ex_cmds/mksession_spec.lua
@@ -5,7 +5,6 @@ local Screen = require('test.functional.ui.screen')
 local clear = helpers.clear
 local command = helpers.command
 local get_pathsep = helpers.get_pathsep
-local iswin = helpers.iswin
 local eq = helpers.eq
 local neq = helpers.neq
 local funcs = helpers.funcs
@@ -15,6 +14,7 @@ local rmdir = helpers.rmdir
 local sleep = helpers.sleep
 local meths = helpers.meths
 local skip = helpers.skip
+local is_os = helpers.is_os
 
 local file_prefix = 'Xtest-functional-ex_cmds-mksession_spec'
 
@@ -178,7 +178,7 @@ describe(':mksession', function()
     command('cd ' .. cwd_dir)
     command('mksession ' .. session_path)
     command('%bwipeout!')
-    if iswin() then
+    if is_os('win') then
       sleep(100) -- Make sure all child processes have exited.
     end
 
@@ -189,13 +189,13 @@ describe(':mksession', function()
     local expected_cwd = cwd_dir .. '/' .. tab_dir
     matches('^term://' .. pesc(expected_cwd) .. '//%d+:', funcs.expand('%'))
     command('%bwipeout!')
-    if iswin() then
+    if is_os('win') then
       sleep(100) -- Make sure all child processes have exited.
     end
   end)
 
   it('restores CWD for :terminal buffer at root directory #16988', function()
-    skip(iswin(), 'N/A for Windows')
+    skip(is_os('win'), 'N/A for Windows')
 
     local screen
     local cwd_dir = funcs.fnamemodify('.', ':p:~'):gsub([[[\/]*$]], '')