summaryrefslogtreecommitdiffstats
path: root/Lib/test/test_threading_local.py
blob: 1567c41000bc59470f4134c1fd83b82a3d487071 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
import sys
import unittest
from doctest import DocTestSuite
from test import support
from test.support import threading_helper
import weakref
import gc

# Modules under test
import _thread
import threading
import _threading_local


class Weak(object):
    pass

def target(local, weaklist):
    weak = Weak()
    local.weak = weak
    weaklist.append(weakref.ref(weak))


class BaseLocalTest:

    def test_local_refs(self):
        self._local_refs(20)
        self._local_refs(50)
        self._local_refs(100)

    def _local_refs(self, n):
        local = self._local()
        weaklist = []
        for i in range(n):
            t = threading.Thread(target=target, args=(local, weaklist))
            t.start()
            t.join()
        del t

        support.gc_collect()  # For PyPy or other GCs.
        self.assertEqual(len(weaklist), n)

        # XXX _threading_local keeps the local of the last stopped thread alive.
        deadlist = [weak for weak in weaklist if weak() is None]
        self.assertIn(len(deadlist), (n-1, n))

        # Assignment to the same thread local frees it sometimes (!)
        local.someothervar = None
        support.gc_collect()  # For PyPy or other GCs.
        deadlist = [weak for weak in weaklist if weak() is None]
        self.assertIn(len(deadlist), (n-1, n), (n, len(deadlist)))

    def test_derived(self):
        # Issue 3088: if there is a threads switch inside the __init__
        # of a threading.local derived class, the per-thread dictionary
        # is created but not correctly set on the object.
        # The first member set may be bogus.
        import time
        class Local(self._local):
            def __init__(self):
                time.sleep(0.01)
        local = Local()

        def f(i):
            local.x = i
            # Simply check that the variable is correctly set
            self.assertEqual(local.x, i)

        with threading_helper.start_threads(threading.Thread(target=f, args=(i,))
                                            for i in range(10)):
            pass

    def test_derived_cycle_dealloc(self):
        # http://bugs.python.org/issue6990
        class Local(self._local):
            pass
        locals = None
        passed = False
        e1 = threading.Event()
        e2 = threading.Event()

        def f():
            nonlocal passed
            # 1) Involve Local in a cycle
            cycle = [Local()]
            cycle.append(cycle)
            cycle[0].foo = 'bar'

            # 2) GC the cycle (triggers threadmodule.c::local_clear
            # before local_dealloc)
            del cycle
            support.gc_collect()  # For PyPy or other GCs.
            e1.set()
            e2.wait()

            # 4) New Locals should be empty
            passed = all(not hasattr(local, 'foo') for local in locals)

        t = threading.Thread(target=f)
        t.start()
        e1.wait()

        # 3) New Locals should recycle the original's address. Creating
        # them in the thread overwrites the thread state and avoids the
        # bug
        locals = [Local() for i in range(10)]
        e2.set()
        t.join()

        self.assertTrue(passed)

    def test_arguments(self):
        # Issue 1522237
        class MyLocal(self._local):
            def __init__(self, *args, **kwargs):
                pass

        MyLocal(a=1)
        MyLocal(1)
        self.assertRaises(TypeError, self._local, a=1)
        self.assertRaises(TypeError, self._local, 1)

    def _test_one_class(self, c):
        self._failed = "No error message set or cleared."
        obj = c()
        e1 = threading.Event()
        e2 = threading.Event()

        def f1():
            obj.x = 'foo'
            obj.y = 'bar'
            del obj.y
            e1.set()
            e2.wait()

        def f2():
            try:
                foo = obj.x
            except AttributeError:
                # This is expected -- we haven't set obj.x in this thread yet!
                self._failed = ""  # passed
            else:
                self._failed = ('Incorrectly got value %r from class %r\n' %
                                (foo, c))
                sys.stderr.write(self._failed)

        t1 = threading.Thread(target=f1)
        t1.start()
        e1.wait()
        t2 = threading.Thread(target=f2)
        t2.start()
        t2.join()
        # The test is done; just let t1 know it can exit, and wait for it.
        e2.set()
        t1.join()

        self.assertFalse(self._failed, self._failed)

    def test_threading_local(self):
        self._test_one_class(self._local)

    def test_threading_local_subclass(self):
        class LocalSubclass(self._local):
            """To test that subclasses behave properly."""
        self._test_one_class(LocalSubclass)

    def _test_dict_attribute(self, cls):
        obj = cls()
        obj.x = 5
        self.assertEqual(obj.__dict__, {'x': 5})
        with self.assertRaises(AttributeError):
            obj.__dict__ = {}
        with self.assertRaises(AttributeError):
            del obj.__dict__

    def test_dict_attribute(self):
        self._test_dict_attribute(self._local)

    def test_dict_attribute_subclass(self):
        class LocalSubclass(self._local):
            """To test that subclasses behave properly."""
        self._test_dict_attribute(LocalSubclass)

    def test_cycle_collection(self):
        class X:
            pass

        x = X()
        x.local = self._local()
        x.local.x = x
        wr = weakref.ref(x)
        del x
        support.gc_collect()  # For PyPy or other GCs.
        self.assertIsNone(wr())


class ThreadLocalTest(unittest.TestCase, BaseLocalTest):
    _local = _thread._local

class PyThreadingLocalTest(unittest.TestCase, BaseLocalTest):
    _local = _threading_local.local


def load_tests(loader, tests, pattern):
    tests.addTest(DocTestSuite('_threading_local'))

    local_orig = _threading_local.local
    def setUp(test):
        _threading_local.local = _thread._local
    def tearDown(test):
        _threading_local.local = local_orig
    tests.addTests(DocTestSuite('_threading_local',
                                setUp=setUp, tearDown=tearDown)
                   )
    return tests


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