scrapy/scrapy/tests/test_utils_python.py

import operator
import unittest

from scrapy.utils.python import str_to_unicode, unicode_to_str, \
    memoizemethod_noargs, isbinarytext, equal_attributes

class UtilsPythonTestCase(unittest.TestCase):
    def test_str_to_unicode(self):
        # converting an utf-8 encoded string to unicode
        self.assertEqual(str_to_unicode('lel\xc3\xb1e'), u'lel\xf1e')

        # converting a latin-1 encoded string to unicode
        self.assertEqual(str_to_unicode('lel\xf1e', 'latin-1'), u'lel\xf1e')

        # converting a unicode to unicode should return the same object
        self.assertEqual(str_to_unicode(u'\xf1e\xf1e\xf1e'), u'\xf1e\xf1e\xf1e')

        # converting a strange object should raise TypeError
        self.assertRaises(TypeError, str_to_unicode, 423)

    def test_unicode_to_str(self):
        # converting a unicode object to an utf-8 encoded string
        self.assertEqual(unicode_to_str(u'\xa3 49'), '\xc2\xa3 49')

        # converting a unicode object to a latin-1 encoded string
        self.assertEqual(unicode_to_str(u'\xa3 49', 'latin-1'), '\xa3 49')

        # converting a regular string to string should return the same object
        self.assertEqual(unicode_to_str('lel\xf1e'), 'lel\xf1e')

        # converting a strange object should raise TypeError
        self.assertRaises(TypeError, unicode_to_str, unittest)

    def test_memoizemethod_noargs(self):
        class A(object):

            @memoizemethod_noargs
            def cached(self):
                return object()

            def noncached(self):
                return object()

        a = A()
        one = a.cached()
        two = a.cached()
        three = a.noncached()
        assert one is two
        assert one is not three

    def test_isbinarytext(self):

        # basic tests
        assert not isbinarytext("hello")

        # utf-16 strings contain null bytes
        assert not isbinarytext(u"hello".encode('utf-16')) 

        # one with encoding
        assert not isbinarytext("<div>Price \xa3</div>")

        # finally some real binary bytes
        assert isbinarytext("\x02\xa3")

    def test_equal_attributes(self):
        class Obj:
            pass

        a = Obj()
        b = Obj()
        # no attributes given return False
        self.failIf(equal_attributes(a, b, []))
        # not existent attributes
        self.failIf(equal_attributes(a, b, ['x', 'y']))

        a.x = 1
        b.x = 1
        # equal attribute
        self.failUnless(equal_attributes(a, b, ['x']))

        b.y = 2
        # obj1 has no attribute y
        self.failIf(equal_attributes(a, b, ['x', 'y']))

        a.y = 2
        # equal attributes
        self.failUnless(equal_attributes(a, b, ['x', 'y']))

        a.y = 1
        # differente attributes
        self.failIf(equal_attributes(a, b, ['x', 'y']))

        # test callable
        a.meta = {}
        b.meta = {}
        self.failUnless(equal_attributes(a, b, ['meta']))

        # compare ['meta']['a']
        a.meta['z'] = 1
        b.meta['z'] = 1

        get_z = operator.itemgetter('z')
        get_meta = operator.attrgetter('meta')
        compare_z = lambda obj: get_z(get_meta(obj))

        self.failUnless(equal_attributes(a, b, [compare_z, 'x']))
        # fail z equality
        a.meta['z'] = 2
        self.failIf(equal_attributes(a, b, [compare_z, 'x']))


if __name__ == "__main__":
    unittest.main()