Lib/test/string_tests.py

"""
Common tests shared by test_str, test_unicode, test_userstring and test_string.
"""

import unittest, string, sys
from test import test_support
from UserList import UserList

class Sequence:
    def __init__(self, seq='wxyz'): self.seq = seq
    def __len__(self): return len(self.seq)
    def __getitem__(self, i): return self.seq[i]

class BadSeq1(Sequence):
    def __init__(self): self.seq = [7, 'hello', 123L]

class BadSeq2(Sequence):
    def __init__(self): self.seq = ['a', 'b', 'c']
    def __len__(self): return 8

class CommonTest(unittest.TestCase):
    # This testcase contains test that can be used in all
    # stringlike classes. Currently this is str, unicode
    # UserString and the string module.

    # The type to be tested
    # Change in subclasses to change the behaviour of fixtesttype()
    type2test = None

    # All tests pass their arguments to the testing methods
    # as str objects. fixtesttype() can be used to propagate
    # these arguments to the appropriate type
    def fixtype(self, obj):
        if isinstance(obj, str):
            return self.__class__.type2test(obj)
        elif isinstance(obj, list):
            return [self.fixtype(x) for x in obj]
        elif isinstance(obj, tuple):
            return tuple([self.fixtype(x) for x in obj])
        elif isinstance(obj, dict):
            return dict([
               (self.fixtype(key), self.fixtype(value))
               for (key, value) in obj.iteritems()
            ])
        else:
            return obj

    # check that object.method(*args) returns result
    def checkequal(self, result, object, methodname, *args):
        result = self.fixtype(result)
        object = self.fixtype(object)
        args = self.fixtype(args)
        realresult = getattr(object, methodname)(*args)
        self.assertEqual(
            result,
            realresult
        )
        # if the original is returned make sure that
        # this doesn't happen with subclasses
        if object == realresult:
            class subtype(self.__class__.type2test):
                pass
            object = subtype(object)
            realresult = getattr(object, methodname)(*args)
            self.assert_(object is not realresult)

    # check that object.method(*args) raises exc
    def checkraises(self, exc, object, methodname, *args):
        object = self.fixtype(object)
        args = self.fixtype(args)
        self.assertRaises(
            exc,
            getattr(object, methodname),
            *args
        )

    # call object.method(*args) without any checks
    def checkcall(self, object, methodname, *args):
        object = self.fixtype(object)
        args = self.fixtype(args)
        getattr(object, methodname)(*args)

    def test_hash(self):
        # SF bug 1054139:  += optimization was not invalidating cached hash value
        a = self.type2test('DNSSEC')
        b = self.type2test('')
        for c in a:
            b += c
            hash(b)
        self.assertEqual(hash(a), hash(b))

    def test_capitalize(self):
        self.checkequal(' hello ', ' hello ', 'capitalize')
        self.checkequal('Hello ', 'Hello ','capitalize')
        self.checkequal('Hello ', 'hello ','capitalize')
        self.checkequal('Aaaa', 'aaaa', 'capitalize')
        self.checkequal('Aaaa', 'AaAa', 'capitalize')

        self.checkraises(TypeError, 'hello', 'capitalize', 42)

    def test_count(self):
        self.checkequal(3, 'aaa', 'count', 'a')
        self.checkequal(0, 'aaa', 'count', 'b')
        self.checkequal(3, 'aaa', 'count', 'a')
        self.checkequal(0, 'aaa', 'count', 'b')
        self.checkequal(3, 'aaa', 'count', 'a')
        self.checkequal(0, 'aaa', 'count', 'b')
        self.checkequal(0, 'aaa', 'count', 'b')
        self.checkequal(1, 'aaa', 'count', 'a', -1)
        self.checkequal(3, 'aaa', 'count', 'a', -10)
        self.checkequal(2, 'aaa', 'count', 'a', 0, -1)
        self.checkequal(0, 'aaa', 'count', 'a', 0, -10)

        self.checkraises(TypeError, 'hello', 'count')
        self.checkraises(TypeError, 'hello', 'count', 42)

        # For a variety of combinations,
        #    verify that str.count() matches an equivalent function
        #    replacing all occurrences and then differencing the string lengths
        charset = ['', 'a', 'b']
        digits = 7
        base = len(charset)
        teststrings = set()
        for i in xrange(base ** digits):
            entry = []
            for j in xrange(digits):
                i, m = divmod(i, base)
                entry.append(charset[m])
            teststrings.add(''.join(entry))
        teststrings = list(teststrings)
        for i in teststrings:
            i = self.fixtype(i)
            n = len(i)
            for j in teststrings:
                r1 = i.count(j)
                if j:
                    r2, rem = divmod(n - len(i.replace(j, '')), len(j))
                else:
                    r2, rem = len(i)+1, 0
                if rem or r1 != r2:
                    self.assertEqual(rem, 0)
                    self.assertEqual(r1, r2)

    def test_find(self):
        self.checkequal(0, 'abcdefghiabc', 'find', 'abc')
        self.checkequal(9, 'abcdefghiabc', 'find', 'abc', 1)
        self.checkequal(-1, 'abcdefghiabc', 'find', 'def', 4)

        self.checkraises(TypeError, 'hello', 'find')
        self.checkraises(TypeError, 'hello', 'find', 42)

        # For a variety of combinations,
        #    verify that str.find() matches __contains__
        #    and that the found substring is really at that location
        charset = ['', 'a', 'b', 'c']
        digits = 5
        base = len(charset)
        teststrings = set()
        for i in xrange(base ** digits):
            entry = []
            for j in xrange(digits):
                i, m = divmod(i, base)
                entry.append(charset[m])
            teststrings.add(''.join(entry))
        teststrings = list(teststrings)
        for i in teststrings:
            i = self.fixtype(i)
            for j in teststrings:
                loc = i.find(j)
                r1 = (loc != -1)
                r2 = j in i
                if r1 != r2:
                    self.assertEqual(r1, r2)
                if loc != -1:
                    self.assertEqual(i[loc:loc+len(j)], j)

    def test_rfind(self):
        self.checkequal(9,  'abcdefghiabc', 'rfind', 'abc')
        self.checkequal(12, 'abcdefghiabc', 'rfind', '')
        self.checkequal(0, 'abcdefghiabc', 'rfind', 'abcd')
        self.checkequal(-1, 'abcdefghiabc', 'rfind', 'abcz')

        self.checkraises(TypeError, 'hello', 'rfind')
        self.checkraises(TypeError, 'hello', 'rfind', 42)

    def test_index(self):
        self.checkequal(0, 'abcdefghiabc', 'index', '')
        self.checkequal(3, 'abcdefghiabc', 'index', 'def')
        self.checkequal(0, 'abcdefghiabc', 'index', 'abc')
        self.checkequal(9, 'abcdefghiabc', 'index', 'abc', 1)

        self.checkraises(ValueError, 'abcdefghiabc', 'index', 'hib')
        self.checkraises(ValueError, 'abcdefghiab', 'index', 'abc', 1)
        self.checkraises(ValueError, 'abcdefghi', 'index', 'ghi', 8)
        self.checkraises(ValueError, 'abcdefghi', 'index', 'ghi', -1)

        self.checkraises(TypeError, 'hello', 'index')
        self.checkraises(TypeError, 'hello', 'index', 42)

    def test_rindex(self):
        self.checkequal(12, 'abcdefghiabc', 'rindex', '')
        self.checkequal(3,  'abcdefghiabc', 'rindex', 'def')
        self.checkequal(9,  'abcdefghiabc', 'rindex', 'abc')
        self.checkequal(0,  'abcdefghiabc', 'rindex', 'abc', 0, -1)

        self.checkraises(ValueError, 'abcdefghiabc', 'rindex', 'hib')
        self.checkraises(ValueError, 'defghiabc', 'rindex', 'def', 1)
        self.checkraises(ValueError, 'defghiabc', 'rindex', 'abc', 0, -1)
        self.checkraises(ValueError, 'abcdefghi', 'rindex', 'ghi', 0, 8)
        self.checkraises(ValueError, 'abcdefghi', 'rindex', 'ghi', 0, -1)

        self.checkraises(TypeError, 'hello', 'rindex')
        self.checkraises(TypeError, 'hello', 'rindex', 42)

    def test_lower(self):
        self.checkequal('hello', 'HeLLo', 'lower')
        self.checkequal('hello', 'hello', 'lower')
        self.checkraises(TypeError, 'hello', 'lower', 42)

    def test_upper(self):
        self.checkequal('HELLO', 'HeLLo', 'upper')
        self.checkequal('HELLO', 'HELLO', 'upper')
        self.checkraises(TypeError, 'hello', 'upper', 42)

    def test_expandtabs(self):
        self.checkequal('abc\rab      def\ng       hi', 'abc\rab\tdef\ng\thi', 'expandtabs')
        self.checkequal('abc\rab      def\ng       hi', 'abc\rab\tdef\ng\thi', 'expandtabs', 8)
        self.checkequal('abc\rab  def\ng   hi', 'abc\rab\tdef\ng\thi', 'expandtabs', 4)
        self.checkequal('abc\r\nab  def\ng   hi', 'abc\r\nab\tdef\ng\thi', 'expandtabs', 4)
        self.checkequal('abc\rab      def\ng       hi', 'abc\rab\tdef\ng\thi', 'expandtabs')
        self.checkequal('abc\rab      def\ng       hi', 'abc\rab\tdef\ng\thi', 'expandtabs', 8)
        self.checkequal('abc\r\nab\r\ndef\ng\r\nhi', 'abc\r\nab\r\ndef\ng\r\nhi', 'expandtabs', 4)

        self.checkraises(TypeError, 'hello', 'expandtabs', 42, 42)

    def test_split(self):
        self.checkequal(['this', 'is', 'the', 'split', 'function'],
            'this is the split function', 'split')

        # by whitespace
        self.checkequal(['a', 'b', 'c', 'd'], 'a b c d ', 'split')
        self.checkequal(['a', 'b c d'], 'a b c d', 'split', None, 1)
        self.checkequal(['a', 'b', 'c d'], 'a b c d', 'split', None, 2)
        self.checkequal(['a', 'b', 'c', 'd'], 'a b c d', 'split', None, 3)
        self.checkequal(['a', 'b', 'c', 'd'], 'a b c d', 'split', None, 4)
        self.checkequal(['a b c d'], 'a b c d', 'split', None, 0)
        self.checkequal(['a', 'b', 'c  d'], 'a  b  c  d', 'split', None, 2)

        # by a char
        self.checkequal(['a', 'b', 'c', 'd'], 'a|b|c|d', 'split', '|')
        self.checkequal(['a', 'b|c|d'], 'a|b|c|d', 'split', '|', 1)
        self.checkequal(['a', 'b', 'c|d'], 'a|b|c|d', 'split', '|', 2)
        self.checkequal(['a', 'b', 'c', 'd'], 'a|b|c|d', 'split', '|', 3)
        self.checkequal(['a', 'b', 'c', 'd'], 'a|b|c|d', 'split', '|', 4)
        self.checkequal(['a|b|c|d'], 'a|b|c|d', 'split', '|', 0)
        self.checkequal(['a', '', 'b||c||d'], 'a||b||c||d', 'split', '|', 2)
        self.checkequal(['endcase ', ''], 'endcase |', 'split', '|')
        self.checkequal(['a', '', 'b\x00c\x00d'], 'a\x00\x00b\x00c\x00d', 'split', '\x00', 2)

        # by string
        self.checkequal(['a', 'b', 'c', 'd'], 'a//b//c//d', 'split', '//')
        self.checkequal(['a', 'b//c//d'], 'a//b//c//d', 'split', '//', 1)
        self.checkequal(['a', 'b', 'c//d'], 'a//b//c//d', 'split', '//', 2)
        self.checkequal(['a', 'b', 'c', 'd'], 'a//b//c//d', 'split', '//', 3)
        self.checkequal(['a', 'b', 'c', 'd'], 'a//b//c//d', 'split', '//', 4)
        self.checkequal(['a//b//c//d'], 'a//b//c//d', 'split', '//', 0)
        self.checkequal(['a', '', 'b////c////d'], 'a////b////c////d', 'split', '//', 2)
        self.checkequal(['endcase ', ''], 'endcase test', 'split', 'test')

        # mixed use of str and unicode
        self.checkequal([u'a', u'b', u'c d'], 'a b c d', 'split', u' ', 2)

        # argument type
        self.checkraises(TypeError, 'hello', 'split', 42, 42, 42)

    def test_rsplit(self):
        self.checkequal(['this', 'is', 'the', 'rsplit', 'function'],
                         'this is the rsplit function', 'rsplit')

        # by whitespace
        self.checkequal(['a', 'b', 'c', 'd'], 'a b c d ', 'rsplit')
        self.checkequal(['a b c', 'd'], 'a b c d', 'rsplit', None, 1)
        self.checkequal(['a b', 'c', 'd'], 'a b c d', 'rsplit', None, 2)
        self.checkequal(['a', 'b', 'c', 'd'], 'a b c d', 'rsplit', None, 3)
        self.checkequal(['a', 'b', 'c', 'd'], 'a b c d', 'rsplit', None, 4)
        self.checkequal(['a b c d'], 'a b c d', 'rsplit', None, 0)
        self.checkequal(['a  b', 'c', 'd'], 'a  b  c  d', 'rsplit', None, 2)

        # by a char
        self.checkequal(['a', 'b', 'c', 'd'], 'a|b|c|d', 'rsplit', '|')
        self.checkequal(['a|b|c', 'd'], 'a|b|c|d', 'rsplit', '|', 1)
        self.checkequal(['a|b', 'c', 'd'], 'a|b|c|d', 'rsplit', '|', 2)
        self.checkequal(['a', 'b', 'c', 'd'], 'a|b|c|d', 'rsplit', '|', 3)
        self.checkequal(['a', 'b', 'c', 'd'], 'a|b|c|d', 'rsplit', '|', 4)
        self.checkequal(['a|b|c|d'], 'a|b|c|d', 'rsplit', '|', 0)
        self.checkequal(['a||b||c', '', 'd'], 'a||b||c||d', 'rsplit', '|', 2)
        self.checkequal(['', ' begincase'], '| begincase', 'rsplit', '|')
        self.checkequal(['a\x00\x00b', 'c', 'd'], 'a\x00\x00b\x00c\x00d', 'rsplit', '\x00', 2)

        # by string
        self.checkequal(['a', 'b', 'c', 'd'], 'a//b//c//d', 'rsplit', '//')
        self.checkequal(['a//b//c', 'd'], 'a//b//c//d', 'rsplit', '//', 1)
        self.checkequal(['a//b', 'c', 'd'], 'a//b//c//d', 'rsplit', '//', 2)
        self.checkequal(['a', 'b', 'c', 'd'], 'a//b//c//d', 'rsplit', '//', 3)
        self.checkequal(['a', 'b', 'c', 'd'], 'a//b//c//d', 'rsplit', '//', 4)
        self.checkequal(['a//b//c//d'], 'a//b//c//d', 'rsplit', '//', 0)
        self.checkequal(['a////b////c', '', 'd'], 'a////b////c////d', 'rsplit', '//', 2)
        self.checkequal(['', ' begincase'], 'test begincase', 'rsplit', 'test')

        # mixed use of str and unicode
        self.checkequal([u'a b', u'c', u'd'], 'a b c d', 'rsplit', u' ', 2)

        # argument type
        self.checkraises(TypeError, 'hello', 'rsplit', 42, 42, 42)

    def test_strip(self):
        self.checkequal('hello', '   hello   ', 'strip')
        self.checkequal('hello   ', '   hello   ', 'lstrip')
        self.checkequal('   hello', '   hello   ', 'rstrip')
        self.checkequal('hello', 'hello', 'strip')

        # strip/lstrip/rstrip with None arg
        self.checkequal('hello', '   hello   ', 'strip', None)
        self.checkequal('hello   ', '   hello   ', 'lstrip', None)
        self.checkequal('   hello', '   hello   ', 'rstrip', None)
        self.checkequal('hello', 'hello', 'strip', None)

        # strip/lstrip/rstrip with str arg
        self.checkequal('hello', 'xyzzyhelloxyzzy', 'strip', 'xyz')
        self.checkequal('helloxyzzy', 'xyzzyhelloxyzzy', 'lstrip', 'xyz')
        self.checkequal('xyzzyhello', 'xyzzyhelloxyzzy', 'rstrip', 'xyz')
        self.checkequal('hello', 'hello', 'strip', 'xyz')

        # strip/lstrip/rstrip with unicode arg
        if test_support.have_unicode:
            self.checkequal(unicode('hello', 'ascii'), 'xyzzyhelloxyzzy',
                 'strip', unicode('xyz', 'ascii'))
            self.checkequal(unicode('helloxyzzy', 'ascii'), 'xyzzyhelloxyzzy',
                 'lstrip', unicode('xyz', 'ascii'))
            self.checkequal(unicode('xyzzyhello', 'ascii'), 'xyzzyhelloxyzzy',
                 'rstrip', unicode('xyz', 'ascii'))
            self.checkequal(unicode('hello', 'ascii'), 'hello',
                 'strip', unicode('xyz', 'ascii'))

        self.checkraises(TypeError, 'hello', 'strip', 42, 42)
        self.checkraises(TypeError, 'hello', 'lstrip', 42, 42)
        self.checkraises(TypeError, 'hello', 'rstrip', 42, 42)

    def test_ljust(self):
        self.checkequal('abc       ', 'abc', 'ljust', 10)
        self.checkequal('abc   ', 'abc', 'ljust', 6)
        self.checkequal('abc', 'abc', 'ljust', 3)
        self.checkequal('abc', 'abc', 'ljust', 2)
        self.checkequal('abc*******', 'abc', 'ljust', 10, '*')
        self.checkraises(TypeError, 'abc', 'ljust')

    def test_rjust(self):
        self.checkequal('       abc', 'abc', 'rjust', 10)
        self.checkequal('   abc', 'abc', 'rjust', 6)
        self.checkequal('abc', 'abc', 'rjust', 3)
        self.checkequal('abc', 'abc', 'rjust', 2)
        self.checkequal('*******abc', 'abc', 'rjust', 10, '*')
        self.checkraises(TypeError, 'abc', 'rjust')

    def test_center(self):
        self.checkequal('   abc    ', 'abc', 'center', 10)
        self.checkequal(' abc  ', 'abc', 'center', 6)
        self.checkequal('abc', 'abc', 'center', 3)
        self.checkequal('abc', 'abc', 'center', 2)
        self.checkequal('***abc****', 'abc', 'center', 10, '*')
        self.checkraises(TypeError, 'abc', 'center')

    def test_swapcase(self):
        self.checkequal('hEllO CoMPuTErS', 'HeLLo cOmpUteRs', 'swapcase')

        self.checkraises(TypeError, 'hello', 'swapcase', 42)

    def test_replace(self):
        EQ = self.checkequal

        # Operations on the empty string
        EQ("", "", "replace", "", "")

        #EQ("A", "", "replace", "", "A")
        # That was the correct result; this is the result we actually get
        # now (for str, but not for unicode):
        #EQ("", "", "replace", "", "A")

        EQ("", "", "replace", "A", "")
        EQ("", "", "replace", "A", "A")
        EQ("", "", "replace", "", "", 100)
        EQ("", "", "replace", "", "", sys.maxint)

        # interleave (from=="", 'to' gets inserted everywhere)
        EQ("A", "A", "replace", "", "")
        EQ("*A*", "A", "replace", "", "*")
        EQ("*1A*1", "A", "replace", "", "*1")
        EQ("*-#A*-#", "A", "replace", "", "*-#")
        EQ("*-A*-A*-", "AA", "replace", "", "*-")
        EQ("*-A*-A*-", "AA", "replace", "", "*-", -1)
        EQ("*-A*-A*-", "AA", "replace", "", "*-", sys.maxint)
        EQ("*-A*-A*-", "AA", "replace", "", "*-", 4)
        EQ("*-A*-A*-", "AA", "replace", "", "*-", 3)
        EQ("*-A*-A", "AA", "replace", "", "*-", 2)
        EQ("*-AA", "AA", "replace", "", "*-", 1)
        EQ("AA", "AA", "replace", "", "*-", 0)

        # single character deletion (from=="A", to=="")
        EQ("", "A", "replace", "A", "")
        EQ("", "AAA", "replace", "A", "")
        EQ("", "AAA", "replace", "A", "", -1)
        EQ("", "AAA", "replace", "A", "", sys.maxint)
        EQ("", "AAA", "replace", "A", "", 4)
        EQ("", "AAA", "replace", "A", "", 3)
        EQ("A", "AAA", "replace", "A", "", 2)
        EQ("AA", "AAA", "replace", "A", "", 1)
        EQ("AAA", "AAA", "replace", "A", "", 0)
        EQ("", "AAAAAAAAAA", "replace", "A", "")
        EQ("BCD", "ABACADA", "replace", "A", "")
        EQ("BCD", "ABACADA", "replace", "A", "", -1)
        EQ("BCD", "ABACADA", "replace", "A", "", sys.maxint)
        EQ("BCD", "ABACADA", "replace", "A", "", 5)
        EQ("BCD", "ABACADA", "replace", "A", "", 4)
        EQ("BCDA", "ABACADA", "replace", "A", "", 3)
        EQ("BCADA", "ABACADA", "replace", "A", "", 2)
        EQ("BACADA", "ABACADA", "replace", "A", "", 1)
        EQ("ABACADA", "ABACADA", "replace", "A", "", 0)
        EQ("BCD", "ABCAD", "replace", "A", "")
        EQ("BCD", "ABCADAA", "replace", "A", "")
        EQ("BCD", "BCD", "replace", "A", "")
        EQ("*************", "*************", "replace", "A", "")
        EQ("^A^", "^"+"A"*1000+"^", "replace", "A", "", 999)

        # substring deletion (from=="the", to=="")
        EQ("", "the", "replace", "the", "")
        EQ("ater", "theater", "replace", "the", "")
        EQ("", "thethe", "replace", "the", "")
        EQ("", "thethethethe", "replace", "the", "")
        EQ("aaaa", "theatheatheathea", "replace", "the", "")
        EQ("that", "that", "replace", "the", "")
        EQ("thaet", "thaet", "replace", "the", "")
        EQ("here and re", "here and there", "replace", "the", "")
        EQ("here and re and re", "here and there and there",
           "replace", "the", "", sys.maxint)
        EQ("here and re and re", "here and there and there",
           "replace", "the", "", -1)
        EQ("here and re and re", "here and there and there",
           "replace", "the", "", 3)
        EQ("here and re and re", "here and there and there",
           "replace", "the", "", 2)
        EQ("here and re and there", "here and there and there",
           "replace", "the", "", 1)
        EQ("here and there and there", "here and there and there",
           "replace", "the", "", 0)
        EQ("here and re and re", "here and there and there", "replace", "the", "")

        EQ("abc", "abc", "replace", "the", "")
        EQ("abcdefg", "abcdefg", "replace", "the", "")

        # substring deletion (from=="bob", to=="")
        EQ("bob", "bbobob", "replace", "bob", "")
        EQ("bobXbob", "bbobobXbbobob", "replace", "bob", "")
        EQ("aaaaaaa", "aaaaaaabob", "replace", "bob", "")
        EQ("aaaaaaa", "aaaaaaa", "replace", "bob", "")

        # single character replace in place (len(from)==len(to)==1)
        EQ("Who goes there?", "Who goes there?", "replace", "o", "o")
        EQ("WhO gOes there?", "Who goes there?", "replace", "o", "O")
        EQ("WhO gOes there?", "Who goes there?", "replace", "o", "O", sys.maxint)
        EQ("WhO gOes there?", "Who goes there?", "replace", "o", "O", -1)
        EQ("WhO gOes there?", "Who goes there?", "replace", "o", "O", 3)
        EQ("WhO gOes there?", "Who goes there?", "replace", "o", "O", 2)
        EQ("WhO goes there?", "Who goes there?", "replace", "o", "O", 1)
        EQ("Who goes there?", "Who goes there?", "replace", "o", "O", 0)

        EQ("Who goes there?", "Who goes there?", "replace", "a", "q")
        EQ("who goes there?", "Who goes there?", "replace", "W", "w")
        EQ("wwho goes there?ww", "WWho goes there?WW", "replace", "W", "w")
        EQ("Who goes there!", "Who goes there?", "replace", "?", "!")
        EQ("Who goes there!!", "Who goes there??", "replace", "?", "!")

        EQ("Who goes there?", "Who goes there?", "replace", ".", "!")

        # substring replace in place (len(from)==len(to) > 1)
        EQ("Th** ** a t**sue", "This is a tissue", "replace", "is", "**")
        EQ("Th** ** a t**sue", "This is a tissue", "replace", "is", "**", sys.maxint)
        EQ("Th** ** a t**sue", "This is a tissue", "replace", "is", "**", -1)
        EQ("Th** ** a t**sue", "This is a tissue", "replace", "is", "**", 4)
        EQ("Th** ** a t**sue", "This is a tissue", "replace", "is", "**", 3)
        EQ("Th** ** a tissue", "This is a tissue", "replace", "is", "**", 2)
        EQ("Th** is a tissue", "This is a tissue", "replace", "is", "**", 1)
        EQ("This is a tissue", "This is a tissue", "replace", "is", "**", 0)
        EQ("cobob", "bobob", "replace", "bob", "cob")
        EQ("cobobXcobocob", "bobobXbobobob", "replace", "bob", "cob")
        EQ("bobob", "bobob", "replace", "bot", "bot")

        # replace single character (len(from)==1, len(to)>1)
        EQ("ReyKKjaviKK", "Reykjavik", "replace", "k", "KK")
        EQ("ReyKKjaviKK", "Reykjavik", "replace", "k", "KK", -1)
        EQ("ReyKKjaviKK", "Reykjavik", "replace", "k", "KK", sys.maxint)
        EQ("ReyKKjaviKK", "Reykjavik", "replace", "k", "KK", 2)
        EQ("ReyKKjavik", "Reykjavik", "replace", "k", "KK", 1)
        EQ("Reykjavik", "Reykjavik", "replace", "k", "KK", 0)
        EQ("A----B----C----", "A.B.C.", "replace", ".", "----")

        EQ("Reykjavik", "Reykjavik", "replace", "q", "KK")

        # replace substring (len(from)>1, len(to)!=len(from))
        EQ("ham, ham, eggs and ham", "spam, spam, eggs and spam",
           "replace", "spam", "ham")
        EQ("ham, ham, eggs and ham", "spam, spam, eggs and spam",
           "replace", "spam", "ham", sys.maxint)
        EQ("ham, ham, eggs and ham", "spam, spam, eggs and spam",
           "replace", "spam", "ham", -1)
        EQ("ham, ham, eggs and ham", "spam, spam, eggs and spam",
           "replace", "spam", "ham", 4)
        EQ("ham, ham, eggs and ham", "spam, spam, eggs and spam",
           "replace", "spam", "ham", 3)
        EQ("ham, ham, eggs and spam", "spam, spam, eggs and spam",
           "replace", "spam", "ham", 2)
        EQ("ham, spam, eggs and spam", "spam, spam, eggs and spam",
           "replace", "spam", "ham", 1)
        EQ("spam, spam, eggs and spam", "spam, spam, eggs and spam",
           "replace", "spam", "ham", 0)

        EQ("bobob", "bobobob", "replace", "bobob", "bob")
        EQ("bobobXbobob", "bobobobXbobobob", "replace", "bobob", "bob")
        EQ("BOBOBOB", "BOBOBOB", "replace", "bob", "bobby")

        #
        self.checkequal('one@two!three!', 'one!two!three!', 'replace', '!', '@', 1)
        self.checkequal('onetwothree', 'one!two!three!', 'replace', '!', '')
        self.checkequal('one@two@three!', 'one!two!three!', 'replace', '!', '@', 2)
        self.checkequal('one@two@three@', 'one!two!three!', 'replace', '!', '@', 3)
        self.checkequal('one@two@three@', 'one!two!three!', 'replace', '!', '@', 4)
        self.checkequal('one!two!three!', 'one!two!three!', 'replace', '!', '@', 0)
        self.checkequal('one@two@three@', 'one!two!three!', 'replace', '!', '@')
        self.checkequal('one!two!three!', 'one!two!three!', 'replace', 'x', '@')
        self.checkequal('one!two!three!', 'one!two!three!', 'replace', 'x', '@', 2)
        self.checkequal('-a-b-c-', 'abc', 'replace', '', '-')
        self.checkequal('-a-b-c', 'abc', 'replace', '', '-', 3)
        self.checkequal('abc', 'abc', 'replace', '', '-', 0)
        self.checkequal('', '', 'replace', '', '')
        self.checkequal('abc', 'abc', 'replace', 'ab', '--', 0)
        self.checkequal('abc', 'abc', 'replace', 'xy', '--')
        # Next three for SF bug 422088: [OSF1 alpha] string.replace(); died with
        # MemoryError due to empty result (platform malloc issue when requesting
        # 0 bytes).
        self.checkequal('', '123', 'replace', '123', '')
        self.checkequal('', '123123', 'replace', '123', '')
        self.checkequal('x', '123x123', 'replace', '123', '')

        self.checkraises(TypeError, 'hello', 'replace')
        self.checkraises(TypeError, 'hello', 'replace', 42)
        self.checkraises(TypeError, 'hello', 'replace', 42, 'h')
        self.checkraises(TypeError, 'hello', 'replace', 'h', 42)

    def test_replace_overflow(self):
        # Check for overflow checking on 32 bit machines
        if sys.maxint != 2147483647:
            return
        A2_16 = "A" * (2**16)
        self.checkraises(OverflowError, A2_16, "replace", "", A2_16)
        self.checkraises(OverflowError, A2_16, "replace", "A", A2_16)
        self.checkraises(OverflowError, A2_16, "replace", "AA", A2_16+A2_16)

    def test_zfill(self):
        self.checkequal('123', '123', 'zfill', 2)
        self.checkequal('123', '123', 'zfill', 3)
        self.checkequal('0123', '123', 'zfill', 4)
        self.checkequal('+123', '+123', 'zfill', 3)
        self.checkequal('+123', '+123', 'zfill', 4)
        self.checkequal('+0123', '+123', 'zfill', 5)
        self.checkequal('-123', '-123', 'zfill', 3)
        self.checkequal('-123', '-123', 'zfill', 4)
        self.checkequal('-0123', '-123', 'zfill', 5)
        self.checkequal('000', '', 'zfill', 3)
        self.checkequal('34', '34', 'zfill', 1)
        self.checkequal('0034', '34', 'zfill', 4)

        self.checkraises(TypeError, '123', 'zfill')

class MixinStrUnicodeUserStringTest:
    # additional tests that only work for
    # stringlike objects, i.e. str, unicode, UserString
    # (but not the string module)

    def test_islower(self):
        self.checkequal(False, '', 'islower')
        self.checkequal(True, 'a', 'islower')
        self.checkequal(False, 'A', 'islower')
        self.checkequal(False, '\n', 'islower')
        self.checkequal(True, 'abc', 'islower')
        self.checkequal(False, 'aBc', 'islower')
        self.checkequal(True, 'abc\n', 'islower')
        self.checkraises(TypeError, 'abc', 'islower', 42)

    def test_isupper(self):
        self.checkequal(False, '', 'isupper')
        self.checkequal(False, 'a', 'isupper')
        self.checkequal(True, 'A', 'isupper')
        self.checkequal(False, '\n', 'isupper')
        self.checkequal(True, 'ABC', 'isupper')
        self.checkequal(False, 'AbC', 'isupper')
        self.checkequal(True, 'ABC\n', 'isupper')
        self.checkraises(TypeError, 'abc', 'isupper', 42)

    def test_istitle(self):
        self.checkequal(False, '', 'istitle')
        self.checkequal(False, 'a', 'istitle')
        self.checkequal(True, 'A', 'istitle')
        self.checkequal(False, '\n', 'istitle')
        self.checkequal(True, 'A Titlecased Line', 'istitle')
        self.checkequal(True, 'A\nTitlecased Line', 'istitle')
        self.checkequal(True, 'A Titlecased, Line', 'istitle')
        self.checkequal(False, 'Not a capitalized String', 'istitle')
        self.checkequal(False, 'Not\ta Titlecase String', 'istitle')
        self.checkequal(False, 'Not--a Titlecase String', 'istitle')
        self.checkequal(False, 'NOT', 'istitle')
        self.checkraises(TypeError, 'abc', 'istitle', 42)

    def test_isspace(self):
        self.checkequal(False, '', 'isspace')
        self.checkequal(False, 'a', 'isspace')
        self.checkequal(True, ' ', 'isspace')
        self.checkequal(True, '\t', 'isspace')
        self.checkequal(True, '\r', 'isspace')
        self.checkequal(True, '\n', 'isspace')
        self.checkequal(True, ' \t\r\n', 'isspace')
        self.checkequal(False, ' \t\r\na', 'isspace')
        self.checkraises(TypeError, 'abc', 'isspace', 42)

    def test_isalpha(self):
        self.checkequal(False, '', 'isalpha')
        self.checkequal(True, 'a', 'isalpha')
        self.checkequal(True, 'A', 'isalpha')
        self.checkequal(False, '\n', 'isalpha')
        self.checkequal(True, 'abc', 'isalpha')
        self.checkequal(False, 'aBc123', 'isalpha')
        self.checkequal(False, 'abc\n', 'isalpha')
        self.checkraises(TypeError, 'abc', 'isalpha', 42)

    def test_isalnum(self):
        self.checkequal(False, '', 'isalnum')
        self.checkequal(True, 'a', 'isalnum')
        self.checkequal(True, 'A', 'isalnum')
        self.checkequal(False, '\n', 'isalnum')
        self.checkequal(True, '123abc456', 'isalnum')
        self.checkequal(True, 'a1b3c', 'isalnum')
        self.checkequal(False, 'aBc000 ', 'isalnum')
        self.checkequal(False, 'abc\n', 'isalnum')
        self.checkraises(TypeError, 'abc', 'isalnum', 42)

    def test_isdigit(self):
        self.checkequal(False, '', 'isdigit')
        self.checkequal(False, 'a', 'isdigit')
        self.checkequal(True, '0', 'isdigit')
        self.checkequal(True, '0123456789', 'isdigit')
        self.checkequal(False, '0123456789a', 'isdigit')

        self.checkraises(TypeError, 'abc', 'isdigit', 42)

    def test_title(self):
        self.checkequal(' Hello ', ' hello ', 'title')
        self.checkequal('Hello ', 'hello ', 'title')
        self.checkequal('Hello ', 'Hello ', 'title')
        self.checkequal('Format This As Title String', "fOrMaT thIs aS titLe String", 'title')
        self.checkequal('Format,This-As*Title;String', "fOrMaT,thIs-aS*titLe;String", 'title', )
        self.checkequal('Getint', "getInt", 'title')
        self.checkraises(TypeError, 'hello', 'title', 42)

    def test_splitlines(self):
        self.checkequal(['abc', 'def', '', 'ghi'], "abc\ndef\n\rghi", 'splitlines')
        self.checkequal(['abc', 'def', '', 'ghi'], "abc\ndef\n\r\nghi", 'splitlines')
        self.checkequal(['abc', 'def', 'ghi'], "abc\ndef\r\nghi", 'splitlines')
        self.checkequal(['abc', 'def', 'ghi'], "abc\ndef\r\nghi\n", 'splitlines')
        self.checkequal(['abc', 'def', 'ghi', ''], "abc\ndef\r\nghi\n\r", 'splitlines')
        self.checkequal(['', 'abc', 'def', 'ghi', ''], "\nabc\ndef\r\nghi\n\r", 'splitlines')
        self.checkequal(['\n', 'abc\n', 'def\r\n', 'ghi\n', '\r'], "\nabc\ndef\r\nghi\n\r", 'splitlines', 1)

        self.checkraises(TypeError, 'abc', 'splitlines', 42, 42)

    def test_startswith(self):
        self.checkequal(True, 'hello', 'startswith', 'he')
        self.checkequal(True, 'hello', 'startswith', 'hello')
        self.checkequal(False, 'hello', 'startswith', 'hello world')
        self.checkequal(True, 'hello', 'startswith', '')
        self.checkequal(False, 'hello', 'startswith', 'ello')
        self.checkequal(True, 'hello', 'startswith', 'ello', 1)
        self.checkequal(True, 'hello', 'startswith', 'o', 4)
        self.checkequal(False, 'hello', 'startswith', 'o', 5)
        self.checkequal(True, 'hello', 'startswith', '', 5)
        self.checkequal(False, 'hello', 'startswith', 'lo', 6)
        self.checkequal(True, 'helloworld', 'startswith', 'lowo', 3)
        self.checkequal(True, 'helloworld', 'startswith', 'lowo', 3, 7)
        self.checkequal(False, 'helloworld', 'startswith', 'lowo', 3, 6)

        # test negative indices
        self.checkequal(True, 'hello', 'startswith', 'he', 0, -1)
        self.checkequal(True, 'hello', 'startswith', 'he', -53, -1)
        self.checkequal(False, 'hello', 'startswith', 'hello', 0, -1)
        self.checkequal(False, 'hello', 'startswith', 'hello world', -1, -10)
        self.checkequal(False, 'hello', 'startswith', 'ello', -5)
        self.checkequal(True, 'hello', 'startswith', 'ello', -4)
        self.checkequal(False, 'hello', 'startswith', 'o', -2)
        self.checkequal(True, 'hello', 'startswith', 'o', -1)
        self.checkequal(True, 'hello', 'startswith', '', -3, -3)
        self.checkequal(False, 'hello', 'startswith', 'lo', -9)

        self.checkraises(TypeError, 'hello', 'startswith')
        self.checkraises(TypeError, 'hello', 'startswith', 42)

    def test_endswith(self):
        self.checkequal(True, 'hello', 'endswith', 'lo')
        self.checkequal(False, 'hello', 'endswith', 'he')
        self.checkequal(True, 'hello', 'endswith', '')
        self.checkequal(False, 'hello', 'endswith', 'hello world')
        self.checkequal(False, 'helloworld', 'endswith', 'worl')
        self.checkequal(True, 'helloworld', 'endswith', 'worl', 3, 9)
        self.checkequal(True, 'helloworld', 'endswith', 'world', 3, 12)
        self.checkequal(True, 'helloworld', 'endswith', 'lowo', 1, 7)
        self.checkequal(True, 'helloworld', 'endswith', 'lowo', 2, 7)
        self.checkequal(True, 'helloworld', 'endswith', 'lowo', 3, 7)
        self.checkequal(False, 'helloworld', 'endswith', 'lowo', 4, 7)
        self.checkequal(False, 'helloworld', 'endswith', 'lowo', 3, 8)
        self.checkequal(False, 'ab', 'endswith', 'ab', 0, 1)
        self.checkequal(False, 'ab', 'endswith', 'ab', 0, 0)

        # test negative indices
        self.checkequal(True, 'hello', 'endswith', 'lo', -2)
        self.checkequal(False, 'hello', 'endswith', 'he', -2)
        self.checkequal(True, 'hello', 'endswith', '', -3, -3)
        self.checkequal(False, 'hello', 'endswith', 'hello world', -10, -2)
        self.checkequal(False, 'helloworld', 'endswith', 'worl', -6)
        self.checkequal(True, 'helloworld', 'endswith', 'worl', -5, -1)
        self.checkequal(True, 'helloworld', 'endswith', 'worl', -5, 9)
        self.checkequal(True, 'helloworld', 'endswith', 'world', -7, 12)
        self.checkequal(True, 'helloworld', 'endswith', 'lowo', -99, -3)
        self.checkequal(True, 'helloworld', 'endswith', 'lowo', -8, -3)
        self.checkequal(True, 'helloworld', 'endswith', 'lowo', -7, -3)
        self.checkequal(False, 'helloworld', 'endswith', 'lowo', 3, -4)
        self.checkequal(False, 'helloworld', 'endswith', 'lowo', -8, -2)

        self.checkraises(TypeError, 'hello', 'endswith')
        self.checkraises(TypeError, 'hello', 'endswith', 42)

    def test___contains__(self):
        self.checkequal(True, '', '__contains__', '')         # vereq('' in '', True)
        self.checkequal(True, 'abc', '__contains__', '')      # vereq('' in 'abc', True)
        self.checkequal(False, 'abc', '__contains__', '\0')   # vereq('\0' in 'abc', False)
        self.checkequal(True, '\0abc', '__contains__', '\0')  # vereq('\0' in '\0abc', True)
        self.checkequal(True, 'abc\0', '__contains__', '\0')  # vereq('\0' in 'abc\0', True)
        self.checkequal(True, '\0abc', '__contains__', 'a')   # vereq('a' in '\0abc', True)
        self.checkequal(True, 'asdf', '__contains__', 'asdf') # vereq('asdf' in 'asdf', True)
        self.checkequal(False, 'asd', '__contains__', 'asdf') # vereq('asdf' in 'asd', False)
        self.checkequal(False, '', '__contains__', 'asdf')    # vereq('asdf' in '', False)

    def test_subscript(self):
        self.checkequal(u'a', 'abc', '__getitem__', 0)
        self.checkequal(u'c', 'abc', '__getitem__', -1)
        self.checkequal(u'a', 'abc', '__getitem__', 0L)
        self.checkequal(u'abc', 'abc', '__getitem__', slice(0, 3))
        self.checkequal(u'abc', 'abc', '__getitem__', slice(0, 1000))
        self.checkequal(u'a', 'abc', '__getitem__', slice(0, 1))
        self.checkequal(u'', 'abc', '__getitem__', slice(0, 0))
        # FIXME What about negative indizes? This is handled differently by [] and __getitem__(slice)

        self.checkraises(TypeError, 'abc', '__getitem__', 'def')

    def test_slice(self):
        self.checkequal('abc', 'abc', '__getslice__', 0, 1000)
        self.checkequal('abc', 'abc', '__getslice__', 0, 3)
        self.checkequal('ab', 'abc', '__getslice__', 0, 2)
        self.checkequal('bc', 'abc', '__getslice__', 1, 3)
        self.checkequal('b', 'abc', '__getslice__', 1, 2)
        self.checkequal('', 'abc', '__getslice__', 2, 2)
        self.checkequal('', 'abc', '__getslice__', 1000, 1000)
        self.checkequal('', 'abc', '__getslice__', 2000, 1000)
        self.checkequal('', 'abc', '__getslice__', 2, 1)
        # FIXME What about negative indizes? This is handled differently by [] and __getslice__

        self.checkraises(TypeError, 'abc', '__getslice__', 'def')

    def test_mul(self):
        self.checkequal('', 'abc', '__mul__', -1)
        self.checkequal('', 'abc', '__mul__', 0)
        self.checkequal('abc', 'abc', '__mul__', 1)
        self.checkequal('abcabcabc', 'abc', '__mul__', 3)
        self.checkraises(TypeError, 'abc', '__mul__')
        self.checkraises(TypeError, 'abc', '__mul__', '')
        # XXX: on a 64-bit system, this doesn't raise an overflow error,
        # but either raises a MemoryError, or succeeds (if you have 54TiB)
        #self.checkraises(OverflowError, 10000*'abc', '__mul__', 2000000000)

    def test_join(self):
        # join now works with any sequence type
        # moved here, because the argument order is
        # different in string.join (see the test in
        # test.test_string.StringTest.test_join)
        self.checkequal('a b c d', ' ', 'join', ['a', 'b', 'c', 'd'])
        self.checkequal('abcd', '', 'join', ('a', 'b', 'c', 'd'))
        self.checkequal('w x y z', ' ', 'join', Sequence())
        self.checkequal('abc', 'a', 'join', ('abc',))
        self.checkequal('z', 'a', 'join', UserList(['z']))
        if test_support.have_unicode:
            self.checkequal(unicode('a.b.c'), unicode('.'), 'join', ['a', 'b', 'c'])
            self.checkequal(unicode('a.b.c'), '.', 'join', [unicode('a'), 'b', 'c'])
            self.checkequal(unicode('a.b.c'), '.', 'join', ['a', unicode('b'), 'c'])
            self.checkequal(unicode('a.b.c'), '.', 'join', ['a', 'b', unicode('c')])
            self.checkraises(TypeError, '.', 'join', ['a', unicode('b'), 3])
        for i in [5, 25, 125]:
            self.checkequal(((('a' * i) + '-') * i)[:-1], '-', 'join',
                 ['a' * i] * i)
            self.checkequal(((('a' * i) + '-') * i)[:-1], '-', 'join',
                 ('a' * i,) * i)

        self.checkraises(TypeError, ' ', 'join', BadSeq1())
        self.checkequal('a b c', ' ', 'join', BadSeq2())

        self.checkraises(TypeError, ' ', 'join')
        self.checkraises(TypeError, ' ', 'join', 7)
        self.checkraises(TypeError, ' ', 'join', Sequence([7, 'hello', 123L]))
        try:
            def f():
                yield 4 + ""
            self.fixtype(' ').join(f())
        except TypeError, e:
            if '+' not in str(e):
                self.fail('join() ate exception message')
        else:
            self.fail('exception not raised')

    def test_formatting(self):
        self.checkequal('+hello+', '+%s+', '__mod__', 'hello')
        self.checkequal('+10+', '+%d+', '__mod__', 10)
        self.checkequal('a', "%c", '__mod__', "a")
        self.checkequal('a', "%c", '__mod__', "a")
        self.checkequal('"', "%c", '__mod__', 34)
        self.checkequal('$', "%c", '__mod__', 36)
        self.checkequal('10', "%d", '__mod__', 10)
        self.checkequal('\x7f', "%c", '__mod__', 0x7f)

        for ordinal in (-100, 0x200000):
            # unicode raises ValueError, str raises OverflowError
            self.checkraises((ValueError, OverflowError), '%c', '__mod__', ordinal)

        self.checkequal(' 42', '%3ld', '__mod__', 42)
        self.checkequal('0042.00', '%07.2f', '__mod__', 42)
        self.checkequal('0042.00', '%07.2F', '__mod__', 42)

        self.checkraises(TypeError, 'abc', '__mod__')
        self.checkraises(TypeError, '%(foo)s', '__mod__', 42)
        self.checkraises(TypeError, '%s%s', '__mod__', (42,))
        self.checkraises(TypeError, '%c', '__mod__', (None,))
        self.checkraises(ValueError, '%(foo', '__mod__', {})
        self.checkraises(TypeError, '%(foo)s %(bar)s', '__mod__', ('foo', 42))

        # argument names with properly nested brackets are supported
        self.checkequal('bar', '%((foo))s', '__mod__', {'(foo)': 'bar'})

        # 100 is a magic number in PyUnicode_Format, this forces a resize
        self.checkequal(103*'a'+'x', '%sx', '__mod__', 103*'a')

        self.checkraises(TypeError, '%*s', '__mod__', ('foo', 'bar'))
        self.checkraises(TypeError, '%10.*f', '__mod__', ('foo', 42.))
        self.checkraises(ValueError, '%10', '__mod__', (42,))

    def test_floatformatting(self):
        # float formatting
        for prec in xrange(100):
            format = '%%.%if' % prec
            value = 0.01
            for x in xrange(60):
                value = value * 3.141592655 / 3.0 * 10.0
                # The formatfloat() code in stringobject.c and
                # unicodeobject.c uses a 120 byte buffer and switches from
                # 'f' formatting to 'g' at precision 50, so we expect
                # OverflowErrors for the ranges x < 50 and prec >= 67.
                if x < 50 and prec >= 67:
                    self.checkraises(OverflowError, format, "__mod__", value)
                else:
                    self.checkcall(format, "__mod__", value)

    def test_inplace_rewrites(self):
        # Check that strings don't copy and modify cached single-character strings
        self.checkequal('a', 'A', 'lower')
        self.checkequal(True, 'A', 'isupper')
        self.checkequal('A', 'a', 'upper')
        self.checkequal(True, 'a', 'islower')

        self.checkequal('a', 'A', 'replace', 'A', 'a')
        self.checkequal(True, 'A', 'isupper')

        self.checkequal('A', 'a', 'capitalize')
        self.checkequal(True, 'a', 'islower')

        self.checkequal('A', 'a', 'swapcase')
        self.checkequal(True, 'a', 'islower')

        self.checkequal('A', 'a', 'title')
        self.checkequal(True, 'a', 'islower')


class MixinStrStringUserStringTest:
    # Additional tests for 8bit strings, i.e. str, UserString and
    # the string module

    def test_maketrans(self):
        self.assertEqual(
           ''.join(map(chr, xrange(256))).replace('abc', 'xyz'),
           string.maketrans('abc', 'xyz')
        )
        self.assertRaises(ValueError, string.maketrans, 'abc', 'xyzw')

    def test_translate(self):
        table = string.maketrans('abc', 'xyz')
        self.checkequal('xyzxyz', 'xyzabcdef', 'translate', table, 'def')

        table = string.maketrans('a', 'A')
        self.checkequal('Abc', 'abc', 'translate', table)
        self.checkequal('xyz', 'xyz', 'translate', table)
        self.checkequal('yz', 'xyz', 'translate', table, 'x')
        self.checkraises(ValueError, 'xyz', 'translate', 'too short', 'strip')
        self.checkraises(ValueError, 'xyz', 'translate', 'too short')


class MixinStrUserStringTest:
    # Additional tests that only work with
    # 8bit compatible object, i.e. str and UserString

    if test_support.have_unicode:
        def test_encoding_decoding(self):
            codecs = [('rot13', 'uryyb jbeyq'),
                      ('base64', 'aGVsbG8gd29ybGQ=\n'),
                      ('hex', '68656c6c6f20776f726c64'),
                      ('uu', 'begin 666 <data>\n+:&5L;&\\@=V]R;&0 \n \nend\n')]
            for encoding, data in codecs:
                self.checkequal(data, 'hello world', 'encode', encoding)
                self.checkequal('hello world', data, 'decode', encoding)
            # zlib is optional, so we make the test optional too...
            try:
                import zlib
            except ImportError:
                pass
            else:
                data = 'x\x9c\xcbH\xcd\xc9\xc9W(\xcf/\xcaI\x01\x00\x1a\x0b\x04]'
                self.checkequal(data, 'hello world', 'encode', 'zlib')
                self.checkequal('hello world', data, 'decode', 'zlib')

            self.checkraises(TypeError, 'xyz', 'decode', 42)
            self.checkraises(TypeError, 'xyz', 'encode', 42)


class MixinStrUnicodeTest:
    # Additional tests that only work with str and unicode.

    def test_bug1001011(self):
        # Make sure join returns a NEW object for single item sequences
        # involving a subclass.
        # Make sure that it is of the appropriate type.
        # Check the optimisation still occurs for standard objects.
        t = self.type2test
        class subclass(t):
            pass
        s1 = subclass("abcd")
        s2 = t().join([s1])
        self.assert_(s1 is not s2)
        self.assert_(type(s2) is t)

        s1 = t("abcd")
        s2 = t().join([s1])
        self.assert_(s1 is s2)

        # Should also test mixed-type join.
        if t is unicode:
            s1 = subclass("abcd")
            s2 = "".join([s1])
            self.assert_(s1 is not s2)
            self.assert_(type(s2) is t)

            s1 = t("abcd")
            s2 = "".join([s1])
            self.assert_(s1 is s2)

        elif t is str:
            s1 = subclass("abcd")
            s2 = u"".join([s1])
            self.assert_(s1 is not s2)
            self.assert_(type(s2) is unicode) # promotes!

            s1 = t("abcd")
            s2 = u"".join([s1])
            self.assert_(s1 is not s2)
            self.assert_(type(s2) is unicode) # promotes!

        else:
            self.fail("unexpected type for MixinStrUnicodeTest %r" % t)