old_contents: 
  import platform
  import sys
  
  platform.python_implementation = lambda:'PyPy'
  
  def unimport():
      del sys.modules['pylibscrypt']
      sys.modules.pop('pylibscrypt.common', None)
      sys.modules.pop('pylibscrypt.mcf', None)
  
  sys.modules['pylibscrypt.pylibscrypt'] = None
  import pylibscrypt
  
  unimport()
  sys.modules['pylibscrypt.pyscrypt'] = None
  import pylibscrypt
  
  unimport()
  sys.modules['pylibscrypt.pylibsodium'] = None
  import pylibscrypt
  
  unimport()
  sys.modules['pylibscrypt.pylibsodium_salsa'] = None
  import pylibscrypt
  
  
new_contents: 
  import platform
  import sys
  
  platform.python_implementation = lambda:'PyPy'
  
  def unimport():
      del sys.modules['pylibscrypt']
      sys.modules.pop('pylibscrypt.common', None)
      sys.modules.pop('pylibscrypt.mcf', None)
  
  sys.modules['pylibscrypt.pylibscrypt'] = None
  import pylibscrypt
  
  unimport()
  sys.modules['pylibscrypt.pyscrypt'] = None
  import pylibscrypt
  
  unimport()
  sys.modules['pylibscrypt.pylibsodium'] = None
  import pylibscrypt
  
  unimport()
  platform.python_implementation = lambda:'CPython'
  import pylibscrypt
  
  unimport()
  sys.modules['pylibscrypt.pylibsodium_salsa'] = None
  import pylibscrypt
  
  
subject: Test both branches of pylibsodium_salsa choice