doc/src/snippets/code/doc_src_q3valuestack.qdoc


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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

//! [0]
Q3ValueStack<int> stack;
stack.push( 1 );
stack.push( 2 );
stack.push( 3 );
while ( ! stack.isEmpty() )
    cout << "Item: " << stack.pop() << endl;

// Output:
//	Item: 3
//	Item: 2
//	Item: 1
//! [0]
"""Unit tests for collections.defaultdict."""

import os
import copy
import pickle
import tempfile
import unittest
from test import support

from collections import defaultdict

def foobar():
    return list

class TestDefaultDict(unittest.TestCase):

    def test_basic(self):
        d1 = defaultdict()
        self.assertEqual(d1.default_factory, None)
        d1.default_factory = list
        d1[12].append(42)
        self.assertEqual(d1, {12: [42]})
        d1[12].append(24)
        self.assertEqual(d1, {12: [42, 24]})
        d1[13]
        d1[14]
        self.assertEqual(d1, {12: [42, 24], 13: [], 14: []})
        self.assertTrue(d1[12] is not d1[13] is not d1[14])
        d2 = defaultdict(list, foo=1, bar=2)
        self.assertEqual(d2.default_factory, list)
        self.assertEqual(d2, {"foo": 1, "bar": 2})
        self.assertEqual(d2["foo"], 1)
        self.assertEqual(d2["bar"], 2)
        self.assertEqual(d2[42], [])
        self.assertIn("foo", d2)
        self.assertIn("foo", d2.keys())
        self.assertIn("bar", d2)
        self.assertIn("bar", d2.keys())
        self.assertIn(42, d2)
        self.assertIn(42, d2.keys())
        self.assertNotIn(12, d2)
        self.assertNotIn(12, d2.keys())
        d2.default_factory = None
        self.assertEqual(d2.default_factory, None)
        try:
            d2[15]
        except KeyError as err:
            self.assertEqual(err.args, (15,))
        else:
            self.fail("d2[15] didn't raise KeyError")
        self.assertRaises(TypeError, defaultdict, 1)

    def test_missing(self):
        d1 = defaultdict()
        self.assertRaises(KeyError, d1.__missing__, 42)
        d1.default_factory = list
        self.assertEqual(d1.__missing__(42), [])

    def test_repr(self):
        d1 = defaultdict()
        self.assertEqual(d1.default_factory, None)
        self.assertEqual(repr(d1), "defaultdict(None, {})")
        self.assertEqual(eval(repr(d1)), d1)
        d1[11] = 41
        self.assertEqual(repr(d1), "defaultdict(None, {11: 41})")
        d2 = defaultdict(int)
        self.assertEqual(d2.default_factory, int)
        d2[12] = 42
        self.assertEqual(repr(d2), "defaultdict(<class 'int'>, {12: 42})")
        def foo(): return 43
        d3 = defaultdict(foo)
        self.assertTrue(d3.default_factory is foo)
        d3[13]
        self.assertEqual(repr(d3), "defaultdict(%s, {13: 43})" % repr(foo))

    def test_print(self):
        d1 = defaultdict()
        def foo(): return 42
        d2 = defaultdict(foo, {1: 2})
        # NOTE: We can't use tempfile.[Named]TemporaryFile since this
        # code must exercise the tp_print C code, which only gets
        # invoked for *real* files.
        tfn = tempfile.mktemp()
        try:
            f = open(tfn, "w+")
            try:
                print(d1, file=f)
                print(d2, file=f)
                f.seek(0)
                self.assertEqual(f.readline(), repr(d1) + "\n")
                self.assertEqual(f.readline(), repr(d2) + "\n")
            finally:
                f.close()
        finally:
            os.remove(tfn)

    def test_copy(self):
        d1 = defaultdict()
        d2 = d1.copy()
        self.assertEqual(type(d2), defaultdict)
        self.assertEqual(d2.default_factory, None)
        self.assertEqual(d2, {})
        d1.default_factory = list
        d3 = d1.copy()
        self.assertEqual(type(d3), defaultdict)
        self.assertEqual(d3.default_factory, list)
        self.assertEqual(d3, {})
        d1[42]
        d4 = d1.copy()
        self.assertEqual(type(d4), defaultdict)
        self.assertEqual(d4.default_factory, list)
        self.assertEqual(d4, {42: []})
        d4[12]
        self.assertEqual(d4, {42: [], 12: []})

        # Issue 6637: Copy fails for empty default dict
        d = defaultdict()
        d['a'] = 42
        e = d.copy()
        self.assertEqual(e['a'], 42)

    def test_shallow_copy(self):
        d1 = defaultdict(foobar, {1: 1})
        d2 = copy.copy(d1)
        self.assertEqual(d2.default_factory, foobar)
        self.assertEqual(d2, d1)
        d1.default_factory = list
        d2 = copy.copy(d1)
        self.assertEqual(d2.default_factory, list)
        self.assertEqual(d2, d1)

    def test_deep_copy(self):
        d1 = defaultdict(foobar, {1: [1]})
        d2 = copy.deepcopy(d1)
        self.assertEqual(d2.default_factory, foobar)
        self.assertEqual(d2, d1)
        self.assertTrue(d1[1] is not d2[1])
        d1.default_factory = list
        d2 = copy.deepcopy(d1)
        self.assertEqual(d2.default_factory, list)
        self.assertEqual(d2, d1)

    def test_keyerror_without_factory(self):
        d1 = defaultdict()
        try:
            d1[(1,)]
        except KeyError as err:
            self.assertEqual(err.args[0], (1,))
        else:
            self.fail("expected KeyError")

    def test_recursive_repr(self):
        # Issue2045: stack overflow when default_factory is a bound method
        class sub(defaultdict):
            def __init__(self):
                self.default_factory = self._factory
            def _factory(self):
                return []
        d = sub()
        self.assertTrue(repr(d).startswith(
            "defaultdict(<bound method sub._factory of defaultdict(..."))

        # NOTE: printing a subclass of a builtin type does not call its
        # tp_print slot. So this part is essentially the same test as above.
        tfn = tempfile.mktemp()
        try:
            f = open(tfn, "w+")
            try:
                print(d, file=f)
            finally:
                f.close()
        finally:
            os.remove(tfn)

    def test_callable_arg(self):
        self.assertRaises(TypeError, defaultdict, {})

    def test_pickleing(self):
        d = defaultdict(int)
        d[1]
        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
            s = pickle.dumps(d, proto)
            o = pickle.loads(s)
            self.assertEqual(d, o)

def test_main():
    support.run_unittest(TestDefaultDict)

if __name__ == "__main__":
    test_main()