Viewing file:  test_descriptor.py (4.71 KB) -rw-r--r--
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"""
Tests for L{epsilon.descriptor}.
"""
from twisted.trial import unittest
from epsilon import descriptor
class Test1(object):
class a(descriptor.attribute):
def get(self):
return 1
def set(self, value):
pass
def delete(self):
pass
class Test2(object):
class a(descriptor.attribute):
"stuff"
def get(self):
return 10
class DescriptorTest(unittest.TestCase):
def testCase1(self):
t = Test1()
self.assertEquals(t.a, 1)
t.a = 2
self.assertEquals(t.a, 1)
del t.a
self.assertEquals(t.a, 1)
def testCase2(self):
t = Test2()
self.assertEquals(Test2.a.__doc__, 'stuff')
self.assertEquals(t.a, 10)
self.assertRaises(AttributeError, setattr, t, 'a', 1)
self.assertRaises(AttributeError, delattr, t, 'a')
class AbstractClassic:
"""
Toy classic class used by L{RequiredAttributeTestCase}.
"""
foo = descriptor.requiredAttribute('foo')
bar = descriptor.requiredAttribute('bar')
class ManifestClassic(AbstractClassic):
"""
Toy classic class used by L{RequiredAttributeTestCase}.
"""
foo = 'bar'
class AbstractNewStyle(object):
"""
Toy new-style class used by L{RequiredAttributeTestCase}.
"""
foo = descriptor.requiredAttribute('foo')
bar = descriptor.requiredAttribute('bar')
class ManifestNewStyle(AbstractNewStyle):
"""
Toy classic class used by L{RequiredAttributeTestCase}.
"""
foo = 'bar'
class RequiredAttributeTestCase(unittest.TestCase):
"""
Tests for L{descriptor.requiredAttribute}.
"""
def _defaultAccess(self, abstractFoo):
exception = self.assertRaises(AttributeError, getattr, abstractFoo, 'foo')
self.assertEqual(len(exception.args), 1)
self.assertEqual(
exception.args[0],
("Required attribute 'foo' has not been changed"
" from its default value on %r" % (abstractFoo,)))
def test_defaultAccessClassic(self):
"""
Accessing a L{descriptor.requiredAttribute} on a classic class raises
an C{AttributeError} if its value has not been overridden.
"""
abstractFoo = AbstractClassic()
self._defaultAccess(abstractFoo)
def test_defaultAccessNewStyle(self):
"""
Accessing a L{descriptor.requiredAttribute} on a new-style class raises
an C{AttributeError} if its value has not been overridden.
"""
abstractFoo = AbstractNewStyle()
self._defaultAccess(abstractFoo)
def _derivedAccess(self, manifestFoo):
self.assertEqual(manifestFoo.foo, 'bar')
def test_derivedAccessClassic(self):
"""
If a derived classic class sets a new value for a
L{descriptor.requiredAttribute}, things should work fine.
"""
manifestFoo = ManifestClassic()
self._derivedAccess(manifestFoo)
def test_derivedAccessNewStyle(self):
"""
If a new-style derived class sets a new value for a
L{descriptor.requiredAttribute}, things should work fine.
"""
manifestFoo = ManifestNewStyle()
self._derivedAccess(manifestFoo)
def _instanceAccess(self, abstractMadeManifest):
abstractMadeManifest.foo = 123
self.assertEqual(abstractMadeManifest.foo, 123)
def test_instanceAccessClassic(self):
"""
Accessing a L{descriptor.requiredAttribute} after setting a value for
it on an instance of a classic class evaluates to that value.
"""
abstractMadeManifest = AbstractClassic()
self._instanceAccess(abstractMadeManifest)
def test_instanceAccessNewStyle(self):
"""
Accessing a L{descriptor.requiredAttribute} after setting a value for
it on an instance of a new-style class evaluates to that value.
"""
abstractMadeManifest = AbstractNewStyle()
self._instanceAccess(abstractMadeManifest)
def test_instanceAttributesUnrelatedClassic(self):
"""
Accessing one L{descriptor.requiredAttribute} after setting a value for
a different L{descriptor.requiredAttribute} raises an
L{AttributeError}.
"""
partiallyAbstract = AbstractClassic()
partiallyAbstract.bar = 123
self._defaultAccess(partiallyAbstract)
def test_instanceAttributesUnrelatedNewStyle(self):
"""
Accessing one L{descriptor.requiredAttribute} after setting a value for
a different L{descriptor.requiredAttribute} raises an
L{AttributeError}.
"""
partiallyAbstract = AbstractNewStyle()
partiallyAbstract.bar = 123
self._defaultAccess(partiallyAbstract)
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