text: # Copyright (c) Twisted Matrix Laboratories.
  # See LICENSE for details.
  
  """
  Tests for L{twisted.python.monkey}.
  """
  
  from __future__ import division, absolute_import
  
  from twisted.trial import unittest
  from twisted.python.monkey import MonkeyPatcher
  
  
  class TestObj:
      def __init__(self):
          self.foo = 'foo value'
          self.bar = 'bar value'
          self.baz = 'baz value'
  
  
  
  class MonkeyPatcherTest(unittest.SynchronousTestCase):
      """
      Tests for L{MonkeyPatcher} monkey-patching class.
      """
  
      def setUp(self):
          self.testObject = TestObj()
          self.originalObject = TestObj()
          self.monkeyPatcher = MonkeyPatcher()
  
  
      def test_empty(self):
          """
          A monkey patcher without patches shouldn't change a thing.
          """
          self.monkeyPatcher.patch()
  
          # We can't assert that all state is unchanged, but at least we can
          # check our test object.
          self.assertEqual(self.originalObject.foo, self.testObject.foo)
          self.assertEqual(self.originalObject.bar, self.testObject.bar)
          self.assertEqual(self.originalObject.baz, self.testObject.baz)
  
  
      def test_constructWithPatches(self):
          """
          Constructing a L{MonkeyPatcher} with patches should add all of the
          given patches to the patch list.
          """
          patcher = MonkeyPatcher((self.testObject, 'foo', 'haha'),
                                  (self.testObject, 'bar', 'hehe'))
          patcher.patch()
          self.assertEqual('haha', self.testObject.foo)
          self.assertEqual('hehe', self.testObject.bar)
          self.assertEqual(self.originalObject.baz, self.testObject.baz)
  
  
      def test_patchExisting(self):
          """
          Patching an attribute that exists sets it to the value defined in the
          patch.
          """
          self.monkeyPatcher.addPatch(self.testObject, 'foo', 'haha')
          self.monkeyPatcher.patch()
          self.assertEqual(self.testObject.foo, 'haha')
  
  
      def test_patchNonExisting(self):
          """
          Patching a non-existing attribute fails with an C{AttributeError}.
          """
          self.monkeyPatcher.addPatch(self.testObject, 'nowhere',
                                      'blow up please')
          self.assertRaises(AttributeError, self.monkeyPatcher.patch)
  
  
      def test_patchAlreadyPatched(self):
          """
          Adding a patch for an object and attribute that already have a patch
          overrides the existing patch.
          """
          self.monkeyPatcher.addPatch(self.testObject, 'foo', 'blah')
          self.monkeyPatcher.addPatch(self.testObject, 'foo', 'BLAH')
          self.monkeyPatcher.patch()
          self.assertEqual(self.testObject.foo, 'BLAH')
          self.monkeyPatcher.restore()
          self.assertEqual(self.testObject.foo, self.originalObject.foo)
  
  
      def test_restoreTwiceIsANoOp(self):
          """
          Restoring an already-restored monkey patch is a no-op.
          """
          self.monkeyPatcher.addPatch(self.testObject, 'foo', 'blah')
          self.monkeyPatcher.patch()
          self.monkeyPatcher.restore()
          self.assertEqual(self.testObject.foo, self.originalObject.foo)
          self.monkeyPatcher.restore()
          self.assertEqual(self.testObject.foo, self.originalObject.foo)
  
  
      def test_runWithPatchesDecoration(self):
          """
          runWithPatches should run the given callable, passing in all arguments
          and keyword arguments, and return the return value of the callable.
          """
          log = []
  
          def f(a, b, c=None):
              log.append((a, b, c))
              return 'foo'
  
          result = self.monkeyPatcher.runWithPatches(f, 1, 2, c=10)
          self.assertEqual('foo', result)
          self.assertEqual([(1, 2, 10)], log)
  
  
      def test_repeatedRunWithPatches(self):
          """
          We should be able to call the same function with runWithPatches more
          than once. All patches should apply for each call.
          """
          def f():
              return (self.testObject.foo, self.testObject.bar,
                      self.testObject.baz)
  
          self.monkeyPatcher.addPatch(self.testObject, 'foo', 'haha')
          result = self.monkeyPatcher.runWithPatches(f)
          self.assertEqual(
              ('haha', self.originalObject.bar, self.originalObject.baz), result)
          result = self.monkeyPatcher.runWithPatches(f)
          self.assertEqual(
              ('haha', self.originalObject.bar, self.originalObject.baz),
              result)
  
  
      def test_runWithPatchesRestores(self):
          """
          C{runWithPatches} should restore the original values after the function
          has executed.
          """
          self.monkeyPatcher.addPatch(self.testObject, 'foo', 'haha')
          self.assertEqual(self.originalObject.foo, self.testObject.foo)
          self.monkeyPatcher.runWithPatches(lambda: None)
          self.assertEqual(self.originalObject.foo, self.testObject.foo)
  
  
      def test_runWithPatchesRestoresOnException(self):
          """
          Test runWithPatches restores the original values even when the function
          raises an exception.
          """
          def _():
              self.assertEqual(self.testObject.foo, 'haha')
              self.assertEqual(self.testObject.bar, 'blahblah')
              raise RuntimeError("Something went wrong!")
  
          self.monkeyPatcher.addPatch(self.testObject, 'foo', 'haha')
          self.monkeyPatcher.addPatch(self.testObject, 'bar', 'blahblah')
  
          self.assertRaises(RuntimeError, self.monkeyPatcher.runWithPatches, _)
          self.assertEqual(self.testObject.foo, self.originalObject.foo)
          self.assertEqual(self.testObject.bar, self.originalObject.bar)
  