summaryrefslogtreecommitdiffstats
path: root/Lib/test/test_raise.py
blob: a41b35377872d02f6ae651f616d4f1f8768fe257 (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
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
# Copyright 2007 Google, Inc. All Rights Reserved.
# Licensed to PSF under a Contributor Agreement.

"""Tests for the raise statement."""

from test import support
import re
import sys
import types
import unittest


def get_tb():
    try:
        raise OSError()
    except:
        return sys.exc_info()[2]


class Context:
    def __enter__(self):
        return self
    def __exit__(self, exc_type, exc_value, exc_tb):
        return True


class TestRaise(unittest.TestCase):
    def test_invalid_reraise(self):
        try:
            raise
        except RuntimeError as e:
            self.assertIn("No active exception", str(e))
        else:
            self.fail("No exception raised")

    def test_reraise(self):
        try:
            try:
                raise IndexError()
            except IndexError as e:
                exc1 = e
                raise
        except IndexError as exc2:
            self.assertTrue(exc1 is exc2)
        else:
            self.fail("No exception raised")

    def test_except_reraise(self):
        def reraise():
            try:
                raise TypeError("foo")
            except:
                try:
                    raise KeyError("caught")
                except KeyError:
                    pass
                raise
        self.assertRaises(TypeError, reraise)

    def test_finally_reraise(self):
        def reraise():
            try:
                raise TypeError("foo")
            except:
                try:
                    raise KeyError("caught")
                finally:
                    raise
        self.assertRaises(KeyError, reraise)

    def test_nested_reraise(self):
        def nested_reraise():
            raise
        def reraise():
            try:
                raise TypeError("foo")
            except:
                nested_reraise()
        self.assertRaises(TypeError, reraise)

    def test_raise_from_None(self):
        try:
            try:
                raise TypeError("foo")
            except:
                raise ValueError() from None
        except ValueError as e:
            self.assertTrue(isinstance(e.__context__, TypeError))
            self.assertIsNone(e.__cause__)

    def test_with_reraise1(self):
        def reraise():
            try:
                raise TypeError("foo")
            except:
                with Context():
                    pass
                raise
        self.assertRaises(TypeError, reraise)

    def test_with_reraise2(self):
        def reraise():
            try:
                raise TypeError("foo")
            except:
                with Context():
                    raise KeyError("caught")
                raise
        self.assertRaises(TypeError, reraise)

    def test_yield_reraise(self):
        def reraise():
            try:
                raise TypeError("foo")
            except:
                yield 1
                raise
        g = reraise()
        next(g)
        self.assertRaises(TypeError, lambda: next(g))
        self.assertRaises(StopIteration, lambda: next(g))

    def test_erroneous_exception(self):
        class MyException(Exception):
            def __init__(self):
                raise RuntimeError()

        try:
            raise MyException
        except RuntimeError:
            pass
        else:
            self.fail("No exception raised")

    def test_new_returns_invalid_instance(self):
        # See issue #11627.
        class MyException(Exception):
            def __new__(cls, *args):
                return object()

        with self.assertRaises(TypeError):
            raise MyException

    def test_assert_with_tuple_arg(self):
        try:
            assert False, (3,)
        except AssertionError as e:
            self.assertEqual(str(e), "(3,)")



class TestCause(unittest.TestCase):

    def testCauseSyntax(self):
        try:
            try:
                try:
                    raise TypeError
                except Exception:
                    raise ValueError from None
            except ValueError as exc:
                self.assertIsNone(exc.__cause__)
                self.assertTrue(exc.__suppress_context__)
                exc.__suppress_context__ = False
                raise exc
        except ValueError as exc:
            e = exc

        self.assertIsNone(e.__cause__)
        self.assertFalse(e.__suppress_context__)
        self.assertIsInstance(e.__context__, TypeError)

    def test_invalid_cause(self):
        try:
            raise IndexError from 5
        except TypeError as e:
            self.assertIn("exception cause", str(e))
        else:
            self.fail("No exception raised")

    def test_class_cause(self):
        try:
            raise IndexError from KeyError
        except IndexError as e:
            self.assertIsInstance(e.__cause__, KeyError)
        else:
            self.fail("No exception raised")

    def test_instance_cause(self):
        cause = KeyError()
        try:
            raise IndexError from cause
        except IndexError as e:
            self.assertTrue(e.__cause__ is cause)
        else:
            self.fail("No exception raised")

    def test_erroneous_cause(self):
        class MyException(Exception):
            def __init__(self):
                raise RuntimeError()

        try:
            raise IndexError from MyException
        except RuntimeError:
            pass
        else:
            self.fail("No exception raised")


class TestTraceback(unittest.TestCase):

    def test_sets_traceback(self):
        try:
            raise IndexError()
        except IndexError as e:
            self.assertIsInstance(e.__traceback__, types.TracebackType)
        else:
            self.fail("No exception raised")

    def test_accepts_traceback(self):
        tb = get_tb()
        try:
            raise IndexError().with_traceback(tb)
        except IndexError as e:
            self.assertNotEqual(e.__traceback__, tb)
            self.assertEqual(e.__traceback__.tb_next, tb)
        else:
            self.fail("No exception raised")


class TestContext(unittest.TestCase):
    def test_instance_context_instance_raise(self):
        context = IndexError()
        try:
            try:
                raise context
            except:
                raise OSError()
        except OSError as e:
            self.assertEqual(e.__context__, context)
        else:
            self.fail("No exception raised")

    def test_class_context_instance_raise(self):
        context = IndexError
        try:
            try:
                raise context
            except:
                raise OSError()
        except OSError as e:
            self.assertNotEqual(e.__context__, context)
            self.assertIsInstance(e.__context__, context)
        else:
            self.fail("No exception raised")

    def test_class_context_class_raise(self):
        context = IndexError
        try:
            try:
                raise context
            except:
                raise OSError
        except OSError as e:
            self.assertNotEqual(e.__context__, context)
            self.assertIsInstance(e.__context__, context)
        else:
            self.fail("No exception raised")

    def test_c_exception_context(self):
        try:
            try:
                1/0
            except:
                raise OSError
        except OSError as e:
            self.assertIsInstance(e.__context__, ZeroDivisionError)
        else:
            self.fail("No exception raised")

    def test_c_exception_raise(self):
        try:
            try:
                1/0
            except:
                xyzzy
        except NameError as e:
            self.assertIsInstance(e.__context__, ZeroDivisionError)
        else:
            self.fail("No exception raised")

    def test_noraise_finally(self):
        try:
            try:
                pass
            finally:
                raise OSError
        except OSError as e:
            self.assertTrue(e.__context__ is None)
        else:
            self.fail("No exception raised")

    def test_raise_finally(self):
        try:
            try:
                1/0
            finally:
                raise OSError
        except OSError as e:
            self.assertIsInstance(e.__context__, ZeroDivisionError)
        else:
            self.fail("No exception raised")

    def test_context_manager(self):
        class ContextManager:
            def __enter__(self):
                pass
            def __exit__(self, t, v, tb):
                xyzzy
        try:
            with ContextManager():
                1/0
        except NameError as e:
            self.assertIsInstance(e.__context__, ZeroDivisionError)
        else:
            self.fail("No exception raised")

    def test_cycle_broken(self):
        # Self-cycles (when re-raising a caught exception) are broken
        try:
            try:
                1/0
            except ZeroDivisionError as e:
                raise e
        except ZeroDivisionError as e:
            self.assertTrue(e.__context__ is None, e.__context__)

    def test_reraise_cycle_broken(self):
        # Non-trivial context cycles (through re-raising a previous exception)
        # are broken too.
        try:
            try:
                xyzzy
            except NameError as a:
                try:
                    1/0
                except ZeroDivisionError:
                    raise a
        except NameError as e:
            self.assertTrue(e.__context__.__context__ is None)

    def test_3118(self):
        # deleting the generator caused the __context__ to be cleared
        def gen():
            try:
                yield 1
            finally:
                pass

        def f():
            g = gen()
            next(g)
            try:
                try:
                    raise ValueError
                except:
                    del g
                    raise KeyError
            except Exception as e:
                self.assertIsInstance(e.__context__, ValueError)

        f()

    def test_3611(self):
        # A re-raised exception in a __del__ caused the __context__
        # to be cleared
        class C:
            def __del__(self):
                try:
                    1/0
                except:
                    raise

        def f():
            x = C()
            try:
                try:
                    x.x
                except AttributeError:
                    del x
                    raise TypeError
            except Exception as e:
                self.assertNotEqual(e.__context__, None)
                self.assertIsInstance(e.__context__, AttributeError)

        with support.captured_output("stderr"):
            f()

class TestRemovedFunctionality(unittest.TestCase):
    def test_tuples(self):
        try:
            raise (IndexError, KeyError) # This should be a tuple!
        except TypeError:
            pass
        else:
            self.fail("No exception raised")

    def test_strings(self):
        try:
            raise "foo"
        except TypeError:
            pass
        else:
            self.fail("No exception raised")


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