old_contents: from rwt import launch
  
  
  def test_with_path(tmpdir, capfd):
  	params = ['-c', 'import sys; print(sys.path)'	]
  	launch.with_path(str(tmpdir), params)
  	out, err = capfd.readouterr()
  	assert str(tmpdir) in out
  
new_contents: import sys
  import subprocess
  import textwrap
  
  from rwt import launch
  
  
  def test_with_path(tmpdir, capfd):
  	params = ['-c', 'import sys; print(sys.path)']
  	launch.with_path(str(tmpdir), params)
  	out, err = capfd.readouterr()
  	assert str(tmpdir) in out
  
  
  def test_with_path_overlay(tmpdir, capfd):
  	params = ['-c', 'import sys; print(sys.path)']
  	# launch subprocess so as not to overlay the test process
  	script = textwrap.dedent("""
  		import rwt.launch
  		rwt.launch.with_path_overlay({tmpdir!r}, {params!r})
  	""").strip().replace('\n', '; ').format(tmpdir=str(tmpdir), params=params)
  	subprocess.Popen([sys.executable, '-c', script]).wait()
  	out, err = capfd.readouterr()
  	assert str(tmpdir) in out
  
subject: Add test for with_path_overlay also.