Python code coverage for Lib/test/test_dynamic.py

#	count	content
1	n/a	# Test the most dynamic corner cases of Python's runtime semantics.
2	n/a
3	n/a	import builtins
4	n/a	import unittest
5	n/a
6	n/a	from test.support import swap_item, swap_attr
7	n/a
8	n/a
9	n/a	class RebindBuiltinsTests(unittest.TestCase):
10	n/a
11	n/a	"""Test all the ways that we can change/shadow globals/builtins."""
12	n/a
13	n/a	def configure_func(self, func, *args):
14	n/a	"""Perform TestCase-specific configuration on a function before testing.
15	n/a
16	n/a	By default, this does nothing. Example usage: spinning a function so
17	n/a	that a JIT will optimize it. Subclasses should override this as needed.
18	n/a
19	n/a	Args:
20	n/a	func: function to configure.
21	n/a	*args: any arguments that should be passed to func, if calling it.
22	n/a
23	n/a	Returns:
24	n/a	Nothing. Work will be performed on func in-place.
25	n/a	"""
26	n/a	pass
27	n/a
28	n/a	def test_globals_shadow_builtins(self):
29	n/a	# Modify globals() to shadow an entry in builtins.
30	n/a	def foo():
31	n/a	return len([1, 2, 3])
32	n/a	self.configure_func(foo)
33	n/a
34	n/a	self.assertEqual(foo(), 3)
35	n/a	with swap_item(globals(), "len", lambda x: 7):
36	n/a	self.assertEqual(foo(), 7)
37	n/a
38	n/a	def test_modify_builtins(self):
39	n/a	# Modify the builtins module directly.
40	n/a	def foo():
41	n/a	return len([1, 2, 3])
42	n/a	self.configure_func(foo)
43	n/a
44	n/a	self.assertEqual(foo(), 3)
45	n/a	with swap_attr(builtins, "len", lambda x: 7):
46	n/a	self.assertEqual(foo(), 7)
47	n/a
48	n/a	def test_modify_builtins_while_generator_active(self):
49	n/a	# Modify the builtins out from under a live generator.
50	n/a	def foo():
51	n/a	x = range(3)
52	n/a	yield len(x)
53	n/a	yield len(x)
54	n/a	self.configure_func(foo)
55	n/a
56	n/a	g = foo()
57	n/a	self.assertEqual(next(g), 3)
58	n/a	with swap_attr(builtins, "len", lambda x: 7):
59	n/a	self.assertEqual(next(g), 7)
60	n/a
61	n/a	def test_modify_builtins_from_leaf_function(self):
62	n/a	# Verify that modifications made by leaf functions percolate up the
63	n/a	# callstack.
64	n/a	with swap_attr(builtins, "len", len):
65	n/a	def bar():
66	n/a	builtins.len = lambda x: 4
67	n/a
68	n/a	def foo(modifier):
69	n/a	l = []
70	n/a	l.append(len(range(7)))
71	n/a	modifier()
72	n/a	l.append(len(range(7)))
73	n/a	return l
74	n/a	self.configure_func(foo, lambda: None)
75	n/a
76	n/a	self.assertEqual(foo(bar), [7, 4])
77	n/a
78	n/a	def test_cannot_change_globals_or_builtins_with_eval(self):
79	n/a	def foo():
80	n/a	return len([1, 2, 3])
81	n/a	self.configure_func(foo)
82	n/a
83	n/a	# Note that this doesn't change the definition of len() seen by foo().
84	n/a	builtins_dict = {"len": lambda x: 7}
85	n/a	globals_dict = {"foo": foo, "__builtins__": builtins_dict,
86	n/a	"len": lambda x: 8}
87	n/a	self.assertEqual(eval("foo()", globals_dict), 3)
88	n/a
89	n/a	self.assertEqual(eval("foo()", {"foo": foo}), 3)
90	n/a
91	n/a	def test_cannot_change_globals_or_builtins_with_exec(self):
92	n/a	def foo():
93	n/a	return len([1, 2, 3])
94	n/a	self.configure_func(foo)
95	n/a
96	n/a	globals_dict = {"foo": foo}
97	n/a	exec("x = foo()", globals_dict)
98	n/a	self.assertEqual(globals_dict["x"], 3)
99	n/a
100	n/a	# Note that this doesn't change the definition of len() seen by foo().
101	n/a	builtins_dict = {"len": lambda x: 7}
102	n/a	globals_dict = {"foo": foo, "__builtins__": builtins_dict,
103	n/a	"len": lambda x: 8}
104	n/a
105	n/a	exec("x = foo()", globals_dict)
106	n/a	self.assertEqual(globals_dict["x"], 3)
107	n/a
108	n/a	def test_cannot_replace_builtins_dict_while_active(self):
109	n/a	def foo():
110	n/a	x = range(3)
111	n/a	yield len(x)
112	n/a	yield len(x)
113	n/a	self.configure_func(foo)
114	n/a
115	n/a	g = foo()
116	n/a	self.assertEqual(next(g), 3)
117	n/a	with swap_item(globals(), "__builtins__", {"len": lambda x: 7}):
118	n/a	self.assertEqual(next(g), 3)
119	n/a
120	n/a	def test_cannot_replace_builtins_dict_between_calls(self):
121	n/a	def foo():
122	n/a	return len([1, 2, 3])
123	n/a	self.configure_func(foo)
124	n/a
125	n/a	self.assertEqual(foo(), 3)
126	n/a	with swap_item(globals(), "__builtins__", {"len": lambda x: 7}):
127	n/a	self.assertEqual(foo(), 3)
128	n/a
129	n/a	def test_eval_gives_lambda_custom_globals(self):
130	n/a	globals_dict = {"len": lambda x: 7}
131	n/a	foo = eval("lambda: len([])", globals_dict)
132	n/a	self.configure_func(foo)
133	n/a
134	n/a	self.assertEqual(foo(), 7)
135	n/a
136	n/a
137	n/a	if __name__ == "__main__":
138	n/a	unittest.main()