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
|
# Copyright 2019 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import re
import sys
import unittest
from py_utils import exc_util
class FakeConnectionError(Exception):
pass
class FakeDisconnectionError(Exception):
pass
class FakeProcessingError(Exception):
pass
class FakeCleanupError(Exception):
pass
class FaultyClient(object):
def __init__(self, *args):
self.failures = set(args)
self.called = set()
def Connect(self):
self.called.add('Connect')
if FakeConnectionError in self.failures:
raise FakeConnectionError('Oops!')
def Process(self):
self.called.add('Process')
if FakeProcessingError in self.failures:
raise FakeProcessingError('Oops!')
@exc_util.BestEffort
def Disconnect(self):
self.called.add('Disconnect')
if FakeDisconnectionError in self.failures:
raise FakeDisconnectionError('Oops!')
@exc_util.BestEffort
def Cleanup(self):
self.called.add('Cleanup')
if FakeCleanupError in self.failures:
raise FakeCleanupError('Oops!')
class ReraiseTests(unittest.TestCase):
def assertLogMatches(self, pattern):
self.assertRegexpMatches(
sys.stderr.getvalue(), pattern) # pylint: disable=no-member
def assertLogNotMatches(self, pattern):
self.assertNotRegexpMatches(
sys.stderr.getvalue(), pattern) # pylint: disable=no-member
def testTryRaisesExceptRaises(self):
client = FaultyClient(FakeConnectionError, FakeDisconnectionError)
# The connection error reaches the top level, while the disconnection
# error is logged.
with self.assertRaises(FakeConnectionError):
try:
client.Connect()
except:
client.Disconnect()
raise
self.assertLogMatches(re.compile(
r'While handling a FakeConnectionError, .* was also raised:\n'
r'Traceback \(most recent call last\):\n'
r'.*\n'
r'FakeDisconnectionError: Oops!\n', re.DOTALL))
self.assertItemsEqual(client.called, ['Connect', 'Disconnect'])
def testTryRaisesExceptDoesnt(self):
client = FaultyClient(FakeConnectionError)
# The connection error reaches the top level, disconnecting did not raise
# an exception (so nothing is logged).
with self.assertRaises(FakeConnectionError):
try:
client.Connect()
except:
client.Disconnect()
raise
self.assertLogNotMatches('FakeDisconnectionError')
self.assertItemsEqual(client.called, ['Connect', 'Disconnect'])
def testTryPassesNoException(self):
client = FaultyClient(FakeDisconnectionError)
# If there is no connection error, the except clause is not called (even if
# it would have raised an exception).
try:
client.Connect()
except:
client.Disconnect()
raise
self.assertLogNotMatches('FakeConnectionError')
self.assertLogNotMatches('FakeDisconnectionError')
self.assertItemsEqual(client.called, ['Connect'])
def testTryRaisesFinallyRaises(self):
worker = FaultyClient(FakeProcessingError, FakeCleanupError)
# The processing error reaches the top level, the cleanup error is logged.
with self.assertRaises(FakeProcessingError):
try:
worker.Process()
except:
raise # Needed for Cleanup to know if an exception is handled.
finally:
worker.Cleanup()
self.assertLogMatches(re.compile(
r'While handling a FakeProcessingError, .* was also raised:\n'
r'Traceback \(most recent call last\):\n'
r'.*\n'
r'FakeCleanupError: Oops!\n', re.DOTALL))
self.assertItemsEqual(worker.called, ['Process', 'Cleanup'])
def testTryRaisesFinallyDoesnt(self):
worker = FaultyClient(FakeProcessingError)
# The processing error reaches the top level, the cleanup code runs fine.
with self.assertRaises(FakeProcessingError):
try:
worker.Process()
except:
raise # Needed for Cleanup to know if an exception is handled.
finally:
worker.Cleanup()
self.assertLogNotMatches('FakeProcessingError')
self.assertLogNotMatches('FakeCleanupError')
self.assertItemsEqual(worker.called, ['Process', 'Cleanup'])
def testTryPassesFinallyRaises(self):
worker = FaultyClient(FakeCleanupError)
# The processing code runs fine, the cleanup code raises an exception
# which reaches the top level.
with self.assertRaises(FakeCleanupError):
try:
worker.Process()
except:
raise # Needed for Cleanup to know if an exception is handled.
finally:
worker.Cleanup()
self.assertLogNotMatches('FakeProcessingError')
self.assertLogNotMatches('FakeCleanupError')
self.assertItemsEqual(worker.called, ['Process', 'Cleanup'])
def testTryRaisesExceptRaisesFinallyRaises(self):
worker = FaultyClient(
FakeProcessingError, FakeDisconnectionError, FakeCleanupError)
# Chaining try-except-finally works fine. Only the processing error reaches
# the top level; the other two are logged.
with self.assertRaises(FakeProcessingError):
try:
worker.Process()
except:
worker.Disconnect()
raise
finally:
worker.Cleanup()
self.assertLogMatches('FakeDisconnectionError')
self.assertLogMatches('FakeCleanupError')
self.assertItemsEqual(worker.called, ['Process', 'Disconnect', 'Cleanup'])
|
