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+" Functions shared by several tests.
+
+" Get the name of the Python executable.
+" Also keeps it in s:python.
+func PythonProg()
+  " This test requires the Python command to run the test server.
+  " This most likely only works on Unix and Windows.
+  if has('unix')
+    " We also need the job feature or the pkill command to make sure the server
+    " can be stopped.
+    if !(executable('python') && (has('job') || executable('pkill')))
+      return ''
+    endif
+    let s:python = 'python'
+  elseif has('win32')
+    " Use Python Launcher for Windows (py.exe) if available.
+    if executable('py.exe')
+      let s:python = 'py.exe'
+    elseif executable('python.exe')
+      let s:python = 'python.exe'
+    else
+      return ''
+    endif
+  else
+    return ''
+  endif
+  return s:python
+endfunc
+
+" Run "cmd".  Returns the job if using a job.
+func RunCommand(cmd)
+  let job = 0
+  if has('job')
+    let job = job_start(a:cmd, {"stoponexit": "hup"})
+    call job_setoptions(job, {"stoponexit": "kill"})
+  elseif has('win32')
+    exe 'silent !start cmd /c start "test_channel" ' . a:cmd
+  else
+    exe 'silent !' . a:cmd . '&'
+  endif
+  return job
+endfunc
+
+" Read the port number from the Xportnr file.
+func GetPort()
+  let l = []
+  for i in range(200)
+    try
+      let l = readfile("Xportnr")
+    catch
+    endtry
+    if len(l) >= 1
+      break
+    endif
+    sleep 10m
+  endfor
+  call delete("Xportnr")
+
+  if len(l) == 0
+    " Can't make the connection, give up.
+    return 0
+  endif
+  return l[0]
+endfunc
+
+" Run a Python server for "cmd" and call "testfunc".
+" Always kills the server before returning.
+func RunServer(cmd, testfunc, args)
+  " The Python program writes the port number in Xportnr.
+  call delete("Xportnr")
+
+  if len(a:args) == 1
+    let arg = ' ' . a:args[0]
+  else
+    let arg = ''
+  endif
+  let pycmd = s:python . " " . a:cmd . arg
+
+  try
+    let g:currentJob = RunCommand(pycmd)
+
+    " Wait for up to 2 seconds for the port number to be there.
+    let port = GetPort()
+    if port == 0
+      call assert_false(1, "Can't start " . a:cmd)
+      return
+    endif
+
+    call call(function(a:testfunc), [port])
+  catch
+    call assert_false(1, "Caught exception: " . v:exception)
+  finally
+    call s:kill_server(a:cmd)
+  endtry
+endfunc
+
+func s:kill_server(cmd)
+  if has('job')
+    if exists('g:currentJob')
+      call job_stop(g:currentJob)
+      unlet g:currentJob
+    endif
+  elseif has('win32')
+    let cmd = substitute(a:cmd, ".py", '', '')
+    call system('taskkill /IM ' . s:python . ' /T /F /FI "WINDOWTITLE eq ' . cmd . '"')
+  else
+    call system("pkill -f " . a:cmd)
+  endif
+endfunc
+
+" Wait for up to a second for "expr" to become true.
+func WaitFor(expr)
+  for i in range(100)
+    try
+      if eval(a:expr)
+	return
+      endif
+    catch
+    endtry
+    sleep 10m
+  endfor
+endfunc