Python code coverage for Lib/test/test_baseexception.py

#	count	content
1	n/a	import unittest
2	n/a	import builtins
3	n/a	import os
4	n/a	from platform import system as platform_system
5	n/a
6	n/a
7	n/a	class ExceptionClassTests(unittest.TestCase):
8	n/a
9	n/a	"""Tests for anything relating to exception objects themselves (e.g.,
10	n/a	inheritance hierarchy)"""
11	n/a
12	n/a	def test_builtins_new_style(self):
13	n/a	self.assertTrue(issubclass(Exception, object))
14	n/a
15	n/a	def verify_instance_interface(self, ins):
16	n/a	for attr in ("args", "__str__", "__repr__"):
17	n/a	self.assertTrue(hasattr(ins, attr),
18	n/a	"%s missing %s attribute" %
19	n/a	(ins.__class__.__name__, attr))
20	n/a
21	n/a	def test_inheritance(self):
22	n/a	# Make sure the inheritance hierarchy matches the documentation
23	n/a	exc_set = set()
24	n/a	for object_ in builtins.__dict__.values():
25	n/a	try:
26	n/a	if issubclass(object_, BaseException):
27	n/a	exc_set.add(object_.__name__)
28	n/a	except TypeError:
29	n/a	pass
30	n/a
31	n/a	inheritance_tree = open(os.path.join(os.path.split(__file__)[0],
32	n/a	'exception_hierarchy.txt'))
33	n/a	try:
34	n/a	superclass_name = inheritance_tree.readline().rstrip()
35	n/a	try:
36	n/a	last_exc = getattr(builtins, superclass_name)
37	n/a	except AttributeError:
38	n/a	self.fail("base class %s not a built-in" % superclass_name)
39	n/a	self.assertIn(superclass_name, exc_set,
40	n/a	'%s not found' % superclass_name)
41	n/a	exc_set.discard(superclass_name)
42	n/a	superclasses = [] # Loop will insert base exception
43	n/a	last_depth = 0
44	n/a	for exc_line in inheritance_tree:
45	n/a	exc_line = exc_line.rstrip()
46	n/a	depth = exc_line.rindex('-')
47	n/a	exc_name = exc_line[depth+2:] # Slice past space
48	n/a	if '(' in exc_name:
49	n/a	paren_index = exc_name.index('(')
50	n/a	platform_name = exc_name[paren_index+1:-1]
51	n/a	exc_name = exc_name[:paren_index-1] # Slice off space
52	n/a	if platform_system() != platform_name:
53	n/a	exc_set.discard(exc_name)
54	n/a	continue
55	n/a	if '[' in exc_name:
56	n/a	left_bracket = exc_name.index('[')
57	n/a	exc_name = exc_name[:left_bracket-1] # cover space
58	n/a	try:
59	n/a	exc = getattr(builtins, exc_name)
60	n/a	except AttributeError:
61	n/a	self.fail("%s not a built-in exception" % exc_name)
62	n/a	if last_depth < depth:
63	n/a	superclasses.append((last_depth, last_exc))
64	n/a	elif last_depth > depth:
65	n/a	while superclasses[-1][0] >= depth:
66	n/a	superclasses.pop()
67	n/a	self.assertTrue(issubclass(exc, superclasses[-1][1]),
68	n/a	"%s is not a subclass of %s" % (exc.__name__,
69	n/a	superclasses[-1][1].__name__))
70	n/a	try: # Some exceptions require arguments; just skip them
71	n/a	self.verify_instance_interface(exc())
72	n/a	except TypeError:
73	n/a	pass
74	n/a	self.assertIn(exc_name, exc_set)
75	n/a	exc_set.discard(exc_name)
76	n/a	last_exc = exc
77	n/a	last_depth = depth
78	n/a	finally:
79	n/a	inheritance_tree.close()
80	n/a	self.assertEqual(len(exc_set), 0, "%s not accounted for" % exc_set)
81	n/a
82	n/a	interface_tests = ("length", "args", "str", "repr")
83	n/a
84	n/a	def interface_test_driver(self, results):
85	n/a	for test_name, (given, expected) in zip(self.interface_tests, results):
86	n/a	self.assertEqual(given, expected, "%s: %s != %s" % (test_name,
87	n/a	given, expected))
88	n/a
89	n/a	def test_interface_single_arg(self):
90	n/a	# Make sure interface works properly when given a single argument
91	n/a	arg = "spam"
92	n/a	exc = Exception(arg)
93	n/a	results = ([len(exc.args), 1], [exc.args[0], arg],
94	n/a	[str(exc), str(arg)],
95	n/a	[repr(exc), exc.__class__.__name__ + repr(exc.args)])
96	n/a	self.interface_test_driver(results)
97	n/a
98	n/a	def test_interface_multi_arg(self):
99	n/a	# Make sure interface correct when multiple arguments given
100	n/a	arg_count = 3
101	n/a	args = tuple(range(arg_count))
102	n/a	exc = Exception(*args)
103	n/a	results = ([len(exc.args), arg_count], [exc.args, args],
104	n/a	[str(exc), str(args)],
105	n/a	[repr(exc), exc.__class__.__name__ + repr(exc.args)])
106	n/a	self.interface_test_driver(results)
107	n/a
108	n/a	def test_interface_no_arg(self):
109	n/a	# Make sure that with no args that interface is correct
110	n/a	exc = Exception()
111	n/a	results = ([len(exc.args), 0], [exc.args, tuple()],
112	n/a	[str(exc), ''],
113	n/a	[repr(exc), exc.__class__.__name__ + '()'])
114	n/a	self.interface_test_driver(results)
115	n/a
116	n/a	class UsageTests(unittest.TestCase):
117	n/a
118	n/a	"""Test usage of exceptions"""
119	n/a
120	n/a	def raise_fails(self, object_):
121	n/a	"""Make sure that raising 'object_' triggers a TypeError."""
122	n/a	try:
123	n/a	raise object_
124	n/a	except TypeError:
125	n/a	return # What is expected.
126	n/a	self.fail("TypeError expected for raising %s" % type(object_))
127	n/a
128	n/a	def catch_fails(self, object_):
129	n/a	"""Catching 'object_' should raise a TypeError."""
130	n/a	try:
131	n/a	try:
132	n/a	raise Exception
133	n/a	except object_:
134	n/a	pass
135	n/a	except TypeError:
136	n/a	pass
137	n/a	except Exception:
138	n/a	self.fail("TypeError expected when catching %s" % type(object_))
139	n/a
140	n/a	try:
141	n/a	try:
142	n/a	raise Exception
143	n/a	except (object_,):
144	n/a	pass
145	n/a	except TypeError:
146	n/a	return
147	n/a	except Exception:
148	n/a	self.fail("TypeError expected when catching %s as specified in a "
149	n/a	"tuple" % type(object_))
150	n/a
151	n/a	def test_raise_new_style_non_exception(self):
152	n/a	# You cannot raise a new-style class that does not inherit from
153	n/a	# BaseException; the ability was not possible until BaseException's
154	n/a	# introduction so no need to support new-style objects that do not
155	n/a	# inherit from it.
156	n/a	class NewStyleClass(object):
157	n/a	pass
158	n/a	self.raise_fails(NewStyleClass)
159	n/a	self.raise_fails(NewStyleClass())
160	n/a
161	n/a	def test_raise_string(self):
162	n/a	# Raising a string raises TypeError.
163	n/a	self.raise_fails("spam")
164	n/a
165	n/a	def test_catch_non_BaseException(self):
166	n/a	# Tryinng to catch an object that does not inherit from BaseException
167	n/a	# is not allowed.
168	n/a	class NonBaseException(object):
169	n/a	pass
170	n/a	self.catch_fails(NonBaseException)
171	n/a	self.catch_fails(NonBaseException())
172	n/a
173	n/a	def test_catch_BaseException_instance(self):
174	n/a	# Catching an instance of a BaseException subclass won't work.
175	n/a	self.catch_fails(BaseException())
176	n/a
177	n/a	def test_catch_string(self):
178	n/a	# Catching a string is bad.
179	n/a	self.catch_fails("spam")
180	n/a
181	n/a
182	n/a	if __name__ == '__main__':
183	n/a	unittest.main()