ci: move BSD jobs from sourcehut to Cirrus CI #19616

dispatch.sr.ht is being deprecated, meaning that using sourcehut CI
won't be possible (see https://github.com/neovim/neovim/issues/19609).
Since Github Actions doesn't provide any BSD runners an external service
is required and Cirrus CI seems like a good replacement for sourcehut.

Initially experimented with using FreeBSD and OpenBSD virtual machines
in GitHub Actions, but Cirrus has been a much better fit with better
performance, logs and overall experience.

Failing tests are automatically skipped on FreeBSD regardless if it's on
CI or not. Ideally these tests should only be skipped in CI with the
help of `isCI` helper function. Unfortunately, the tests don't recognize
the environment variable CIRRUS_CI even if it's set manually. This
workaround is good enough for the time being, but we might want to only
skip tests when using the CI (or even better, fix the failing tests).

Closes: https://github.com/neovim/neovim/issues/19609

test/functional/api/server_notifications_spec.lua

@@ -7,6 +7,7 @@ local exec_lua = helpers.exec_lua
 local retry = helpers.retry
 local isCI = helpers.isCI
 local assert_alive = helpers.assert_alive
+local uname = helpers.uname
 
 describe('notify', function()
   local channel
@@ -78,6 +79,9 @@ describe('notify', function()
   end)
 
   it('cancels stale events on channel close', function()
+    if uname() == 'freebsd' then
+      pending('Failing FreeBSD test')
+    end
     if isCI() then
       pending('hangs on CI #14083 #15251')
       return

test/functional/core/fileio_spec.lua

@@ -23,6 +23,7 @@ local iswin = helpers.iswin
 local assert_alive = helpers.assert_alive
 local expect_exit = helpers.expect_exit
 local write_file = helpers.write_file
+local uname = helpers.uname
 
 describe('fileio', function()
   before_each(function()
@@ -83,6 +84,9 @@ describe('fileio', function()
   end)
 
   it('backup #9709', function()
+    if uname() == 'freebsd' then
+      pending('Failing FreeBSD test')
+    end
     clear({ args={ '-i', 'Xtest_startup_shada',
                    '--cmd', 'set directory=Xtest_startup_swapdir' } })
 
@@ -102,6 +106,9 @@ describe('fileio', function()
   end)
 
   it('backup with full path #11214', function()
+    if uname() == 'freebsd' then
+      pending('Failing FreeBSD test')
+    end
     clear()
     mkdir('Xtest_backupdir')
     command('set backup')

test/functional/ex_cmds/write_spec.lua

@@ -9,6 +9,7 @@ local feed_command = helpers.feed_command
 local funcs = helpers.funcs
 local meths = helpers.meths
 local iswin = helpers.iswin
+local uname = helpers.uname
 
 local fname = 'Xtest-functional-ex_cmds-write'
 local fname_bak = fname .. '~'
@@ -52,6 +53,9 @@ describe(':write', function()
   end)
 
   it('&backupcopy=no replaces symlink with new file', function()
+    if uname() == 'freebsd' then
+      pending('Failing FreeBSD test')
+    end
     command('set backupcopy=no')
     write_file('test_bkc_file.txt', 'content0')
     if iswin() then
@@ -91,6 +95,9 @@ describe(':write', function()
   end)
 
   it('errors out correctly', function()
+    if uname() == 'freebsd' then
+      pending('Failing FreeBSD test')
+    end
     command('let $HOME=""')
     eq(funcs.fnamemodify('.', ':p:h'), funcs.fnamemodify('.', ':p:h:~'))
     -- Message from check_overwrite

test/functional/terminal/ex_terminal_spec.lua

@@ -10,6 +10,7 @@ local retry = helpers.retry
 local ok = helpers.ok
 local iswin = helpers.iswin
 local command = helpers.command
+local uname = helpers.uname
 
 describe(':terminal', function()
   local screen
@@ -45,6 +46,9 @@ describe(':terminal', function()
   end)
 
   it("reads output buffer on terminal reporting #4151", function()
+    if uname() == 'freebsd' then
+      pending('Failing FreeBSD test')
+    end
     if helpers.pending_win32(pending) then return end
     if iswin() then
       feed_command([[terminal powershell -NoProfile -NoLogo -Command Write-Host -NoNewline "\"$([char]27)[6n\""; Start-Sleep -Milliseconds 500 ]])