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# Copyright (c) Twisted Matrix Laboratories.
# See LICENSE for details.
"""
Tests for L{twisted.python.monkey}.
"""
from twisted.python.monkey import MonkeyPatcher
from twisted.trial import unittest
class TestObj:
def __init__(self):
self.foo = "foo value"
self.bar = "bar value"
self.baz = "baz value"
class MonkeyPatcherTests(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)
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