diff --git a/autoload/vimspector/internal/job.vim b/autoload/vimspector/internal/job.vim
index a93a004..692f914 100644
--- a/autoload/vimspector/internal/job.vim
+++ b/autoload/vimspector/internal/job.vim
@@ -20,11 +20,8 @@ set cpoptions&vim
 " }}}
 
 function! s:_OnServerData( channel, data ) abort
-  if py3eval( '_vimspector_session is None' )
-    call ch_log( 'Unexpected stdout data received on channel '
-               \ . a:channel
-               \ . 'after reset: '
-               \ . a:data )
+  if !exists( 's:job' )
+    call ch_log( 'Get data after process exit' )
     return
   endif
 
@@ -32,11 +29,8 @@ function! s:_OnServerData( channel, data ) abort
 endfunction
 
 function! s:_OnServerError( channel, data ) abort
-  if py3eval( '_vimspector_session is None' )
-    call ch_log( 'Unexpected stderr data received on channel '
-               \ . a:channel
-               \ . 'after reset: '
-               \ . a:data )
+  if !exists( 's:job' )
+    call ch_log( 'Get data after process exit' )
     return
   endif
 
diff --git a/python3/vimspector/debug_session.py b/python3/vimspector/debug_session.py
index 50b2b00..88d1167 100644
--- a/python3/vimspector/debug_session.py
+++ b/python3/vimspector/debug_session.py
@@ -300,6 +300,10 @@ class DebugSession( object ):
     return wrapper
 
   def OnChannelData( self, data ):
+    if self._connection is None:
+      # Should _not_ happen, but maybe possible due to races or vim bufs?
+      return
+
     self._connection.OnData( data )
 
 
@@ -969,7 +973,9 @@ class DebugSession( object ):
 
     if self._run_on_server_exit:
       self._logger.debug( "Running server exit handler" )
-      self._run_on_server_exit()
+      callback = self._run_on_server_exit
+      self._run_on_server_exit = None
+      callback()
     else:
       self._logger.debug( "No server exit handler" )
 
diff --git a/tests/lib/plugin/shared.vim b/tests/lib/plugin/shared.vim
index ee9a0af..d682810 100644
--- a/tests/lib/plugin/shared.vim
+++ b/tests/lib/plugin/shared.vim
@@ -6,115 +6,6 @@ if exists('*WaitFor')
   finish
 endif
 
-" 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 = []
-  " with 200 it sometimes failed
-  for i in range(400)
-    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 . '" in ' . v:throwpoint)
-  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 five seconds for "expr" to become true.  "expr" can be a
 " stringified expression to evaluate, or a funcref without arguments.
 " Using a lambda works best.  Example:
@@ -180,7 +71,10 @@ func s:WaitForCommon(expr, assert, timeout)
 
     if type(a:assert) == v:t_func
       " Remove the errors added by the assert function.
-      call remove(v:errors, -1 * len( v:errors ) - errors_before )
+      let errors_added = len( v:errors ) - errors_before
+      if errors_added > 0
+        call remove(v:errors, -1 * errors_added )
+      endif
     endif
 
     sleep 10m
@@ -193,170 +87,3 @@ func s:WaitForCommon(expr, assert, timeout)
 
   return -1  " timed out
 endfunc
-
-
-" Wait for up to a given milliseconds.
-" With the +timers feature this waits for key-input by getchar(), Resume()
-" feeds key-input and resumes process. Return time waited in milliseconds.
-" Without +timers it uses simply :sleep.
-func Standby(msec)
-  if has('timers')
-    let start = reltime()
-    let g:_standby_timer = timer_start(a:msec, function('s:feedkeys'))
-    call getchar()
-    return float2nr(reltimefloat(reltime(start)) * 1000)
-  else
-    execute 'sleep ' a:msec . 'm'
-    return a:msec
-  endif
-endfunc
-
-func Resume()
-  if exists('g:_standby_timer')
-    call timer_stop(g:_standby_timer)
-    call s:feedkeys(0)
-    unlet g:_standby_timer
-  endif
-endfunc
-
-func s:feedkeys(timer)
-  call feedkeys('x', 'nt')
-endfunc
-
-" Get $VIMPROG to run Vim executable.
-" The Makefile writes it as the first line in the "vimcmd" file.
-func GetVimProg()
-  if !filereadable('vimcmd')
-    " Assume the script was sourced instead of running "make".
-    return '../vim'
-  endif
-  return readfile('vimcmd')[0]
-endfunc
-
-let g:valgrind_cnt = 1
-
-" Get the command to run Vim, with -u NONE and --not-a-term arguments.
-" If there is an argument use it instead of "NONE".
-func GetVimCommand(...)
-  if !filereadable('vimcmd')
-    echo 'Cannot read the "vimcmd" file, falling back to ../vim.'
-    let lines = ['../vim']
-  else
-    let lines = readfile('vimcmd')
-  endif
-  if a:0 == 0
-    let name = 'NONE'
-  else
-    let name = a:1
-  endif
-  " For Unix Makefile writes the command to use in the second line of the
-  " "vimcmd" file, including environment options.
-  " Other Makefiles just write the executable in the first line, so fall back
-  " to that if there is no second line or it is empty.
-  if len(lines) > 1 && lines[1] !=# ''
-    let cmd = lines[1]
-  else
-    let cmd = lines[0]
-  endif
-
-  let cmd = substitute(cmd, '-u \f\+', '-u ' . name, '')
-  if cmd !~ '-u '. name
-    let cmd = cmd . ' -u ' . name
-  endif
-  let cmd .= ' --not-a-term'
-  let cmd = substitute(cmd, 'VIMRUNTIME=.*VIMRUNTIME;', '', '')
-
-  " If using valgrind, make sure every run uses a different log file.
-  if cmd =~# 'valgrind.*--log-file='
-    let cmd = substitute(cmd, '--log-file=\(^\s*\)', '--log-file=\1.' . g:valgrind_cnt, '')
-    let g:valgrind_cnt += 1
-  endif
-
-  return cmd
-endfunc
-
-" Get the command to run Vim, with --clean.
-func GetVimCommandClean()
-  let cmd = GetVimCommand()
-  let cmd = substitute(cmd, '-u NONE', '--clean', '')
-  let cmd = substitute(cmd, '--not-a-term', '', '')
-
-  " Optionally run Vim under valgrind
-  " let cmd = 'valgrind --tool=memcheck --leak-check=yes --num-callers=25 --log-file=valgrind ' . cmd
-
-  return cmd
-endfunc
-
-" Run Vim, using the "vimcmd" file and "-u NORC".
-" "before" is a list of Vim commands to be executed before loading plugins.
-" "after" is a list of Vim commands to be executed after loading plugins.
-" Plugins are not loaded, unless 'loadplugins' is set in "before".
-" Return 1 if Vim could be executed.
-func RunVim(before, after, arguments)
-  return RunVimPiped(a:before, a:after, a:arguments, '')
-endfunc
-
-func RunVimPiped(before, after, arguments, pipecmd)
-  let cmd = GetVimCommand()
-  let args = ''
-  if len(a:before) > 0
-    call writefile(a:before, 'Xbefore.vim')
-    let args .= ' --cmd "so Xbefore.vim"'
-  endif
-  if len(a:after) > 0
-    call writefile(a:after, 'Xafter.vim')
-    let args .= ' -S Xafter.vim'
-  endif
-
-  exe 'silent !' . a:pipecmd . cmd . args . ' ' . a:arguments
-
-  if len(a:before) > 0
-    call delete('Xbefore.vim')
-  endif
-  if len(a:after) > 0
-    call delete('Xafter.vim')
-  endif
-  return 1
-endfunc
-
-func CanRunGui()
-  return has('gui') && ($DISPLAY !=# '' || has('gui_running'))
-endfunc
-
-func WorkingClipboard()
-  if !has('clipboard')
-    return 0
-  endif
-  if has('x11')
-    return $DISPLAY !=# ''
-  endif
-  return 1
-endfunc
-
-" Get line "lnum" as displayed on the screen.
-" Trailing white space is trimmed.
-func! Screenline(lnum)
-  let chars = []
-  for c in range(1, winwidth(0))
-    call add(chars, nr2char(screenchar(a:lnum, c)))
-  endfor
-  let line = join(chars, '')
-  return matchstr(line, '^.\{-}\ze\s*$')
-endfunc
-
-" Stops the shell running in terminal "buf".
-func Stop_shell_in_terminal(buf)
-  call term_sendkeys(a:buf, "exit\r")
-  let job = term_getjob(a:buf)
-  call WaitFor({-> job_status(job) == "dead"})
-endfunc
-
-" Gets the text of a terminal line, using term_scrape()
-func Get_terminal_text(bufnr, row)
-  let list = term_scrape(a:bufnr, a:row)
-  let text = ''
-  for item in list
-    let text .= item.chars
-  endfor
-  return text
-endfunc