twisted/internet/test/test_baseprocess.py

   1 # Copyright (c) Twisted Matrix Laboratories.
   2 # See LICENSE for details.
   3
   4 """
   5 Tests for L{twisted.internet._baseprocess} which implements process-related
   6 functionality that is useful in all platforms supporting L{IReactorProcess}.
   7 """
   8
   9 __metaclass__ = type
  10
  11 from twisted.python.deprecate import getWarningMethod, setWarningMethod
  12 from twisted.trial.unittest import TestCase
  13 from twisted.internet._baseprocess import BaseProcess
  14
  15
  16 class BaseProcessTests(TestCase):
  17     """
  18     Tests for L{BaseProcess}, a parent class for other classes which represent
  19     processes which implements functionality common to many different process
  20     implementations.
  21     """
  22     def test_callProcessExited(self):
  23         """
  24         L{BaseProcess._callProcessExited} calls the C{processExited} method of
  25         its C{proto} attribute and passes it a L{Failure} wrapping the given
  26         exception.
  27         """
  28         class FakeProto:
  29             reason = None
  30
  31             def processExited(self, reason):
  32                 self.reason = reason
  33
  34         reason = RuntimeError("fake reason")
  35         process = BaseProcess(FakeProto())
  36         process._callProcessExited(reason)
  37         process.proto.reason.trap(RuntimeError)
  38         self.assertIdentical(reason, process.proto.reason.value)
  39
  40
  41     def test_callProcessExitedMissing(self):
  42         """
  43         L{BaseProcess._callProcessExited} emits a L{DeprecationWarning} if the
  44         object referred to by its C{proto} attribute has no C{processExited}
  45         method.
  46         """
  47         class FakeProto:
  48             pass
  49
  50         reason = object()
  51         process = BaseProcess(FakeProto())
  52
  53         self.addCleanup(setWarningMethod, getWarningMethod())
  54         warnings = []
  55         def collect(message, category, stacklevel):
  56             warnings.append((message, category, stacklevel))
  57         setWarningMethod(collect)
  58
  59         process._callProcessExited(reason)
  60
  61         [(message, category, stacklevel)] = warnings
  62         self.assertEqual(
  63             message,
  64             "Since Twisted 8.2, IProcessProtocol.processExited is required.  "
  65             "%s.%s must implement it." % (
  66                 FakeProto.__module__, FakeProto.__name__))
  67         self.assertIdentical(category, DeprecationWarning)
  68         # The stacklevel doesn't really make sense for this kind of
  69         # deprecation.  Requiring it to be 0 will at least avoid pointing to
  70         # any part of Twisted or a random part of the application's code, which
  71         # I think would be more misleading than having it point inside the
  72         # warning system itself. -exarkun
  73         self.assertEqual(stacklevel, 0)