Python code coverage for Modules/_decimal/tests/randfloat.py

#	count	content
1	n/a	# Copyright (c) 2010 Python Software Foundation. All Rights Reserved.
2	n/a	# Adapted from Python's Lib/test/test_strtod.py (by Mark Dickinson)
3	n/a
4	n/a	# More test cases for deccheck.py.
5	n/a
6	n/a	import random
7	n/a
8	n/a	TEST_SIZE = 2
9	n/a
10	n/a
11	n/a	def test_short_halfway_cases():
12	n/a	# exact halfway cases with a small number of significant digits
13	n/a	for k in 0, 5, 10, 15, 20:
14	n/a	# upper = smallest integer >= 254/5k
15	n/a	upper = -(-254//5k)
16	n/a	# lower = smallest odd number >= 253/5k
17	n/a	lower = -(-253//5k)
18	n/a	if lower % 2 == 0:
19	n/a	lower += 1
20	n/a	for i in range(10 * TEST_SIZE):
21	n/a	# Select a random odd n in [253/5k,
22	n/a	# 254/5k). Then n * 10**k gives a halfway case
23	n/a	# with small number of significant digits.
24	n/a	n, e = random.randrange(lower, upper, 2), k
25	n/a
26	n/a	# Remove any additional powers of 5.
27	n/a	while n % 5 == 0:
28	n/a	n, e = n // 5, e + 1
29	n/a	assert n % 10 in (1, 3, 7, 9)
30	n/a
31	n/a	# Try numbers of the form n * 2*p2 10**e, p2 >= 0,
32	n/a	# until n * 2**p2 has more than 20 significant digits.
33	n/a	digits, exponent = n, e
34	n/a	while digits < 10**20:
35	n/a	s = '{}e{}'.format(digits, exponent)
36	n/a	yield s
37	n/a	# Same again, but with extra trailing zeros.
38	n/a	s = '{}e{}'.format(digits * 10**40, exponent - 40)
39	n/a	yield s
40	n/a	digits *= 2
41	n/a
42	n/a	# Try numbers of the form n * 5*p2 10**(e - p5), p5
43	n/a	# >= 0, with n * 5p5 < 1020.
44	n/a	digits, exponent = n, e
45	n/a	while digits < 10**20:
46	n/a	s = '{}e{}'.format(digits, exponent)
47	n/a	yield s
48	n/a	# Same again, but with extra trailing zeros.
49	n/a	s = '{}e{}'.format(digits * 10**40, exponent - 40)
50	n/a	yield s
51	n/a	digits *= 5
52	n/a	exponent -= 1
53	n/a
54	n/a	def test_halfway_cases():
55	n/a	# test halfway cases for the round-half-to-even rule
56	n/a	for i in range(1000):
57	n/a	for j in range(TEST_SIZE):
58	n/a	# bit pattern for a random finite positive (or +0.0) float
59	n/a	bits = random.randrange(20472*52)
60	n/a
61	n/a	# convert bit pattern to a number of the form m * 2**e
62	n/a	e, m = divmod(bits, 2**52)
63	n/a	if e:
64	n/a	m, e = m + 2**52, e - 1
65	n/a	e -= 1074
66	n/a
67	n/a	# add 0.5 ulps
68	n/a	m, e = 2*m + 1, e - 1
69	n/a
70	n/a	# convert to a decimal string
71	n/a	if e >= 0:
72	n/a	digits = m << e
73	n/a	exponent = 0
74	n/a	else:
75	n/a	# m * 2*e = (m 5*-e) 10**e
76	n/a	digits = m * 5**-e
77	n/a	exponent = e
78	n/a	s = '{}e{}'.format(digits, exponent)
79	n/a	yield s
80	n/a
81	n/a	def test_boundaries():
82	n/a	# boundaries expressed as triples (n, e, u), where
83	n/a	# n10*e is an approximation to the boundary value and
84	n/a	# u10*e is 1ulp
85	n/a	boundaries = [
86	n/a	(10000000000000000000, -19, 1110), # a power of 2 boundary (1.0)
87	n/a	(17976931348623159077, 289, 1995), # overflow boundary (2.**1024)
88	n/a	(22250738585072013831, -327, 4941), # normal/subnormal (2.**-1022)
89	n/a	(0, -327, 4941), # zero
90	n/a	]
91	n/a	for n, e, u in boundaries:
92	n/a	for j in range(1000):
93	n/a	for i in range(TEST_SIZE):
94	n/a	digits = n + random.randrange(-3u, 3u)
95	n/a	exponent = e
96	n/a	s = '{}e{}'.format(digits, exponent)
97	n/a	yield s
98	n/a	n *= 10
99	n/a	u *= 10
100	n/a	e -= 1
101	n/a
102	n/a	def test_underflow_boundary():
103	n/a	# test values close to 2**-1075, the underflow boundary; similar
104	n/a	# to boundary_tests, except that the random error doesn't scale
105	n/a	# with n
106	n/a	for exponent in range(-400, -320):
107	n/a	base = 10-exponent // 21075
108	n/a	for j in range(TEST_SIZE):
109	n/a	digits = base + random.randrange(-1000, 1000)
110	n/a	s = '{}e{}'.format(digits, exponent)
111	n/a	yield s
112	n/a
113	n/a	def test_bigcomp():
114	n/a	for ndigs in 5, 10, 14, 15, 16, 17, 18, 19, 20, 40, 41, 50:
115	n/a	dig10 = 10**ndigs
116	n/a	for i in range(100 * TEST_SIZE):
117	n/a	digits = random.randrange(dig10)
118	n/a	exponent = random.randrange(-400, 400)
119	n/a	s = '{}e{}'.format(digits, exponent)
120	n/a	yield s
121	n/a
122	n/a	def test_parsing():
123	n/a	# make '0' more likely to be chosen than other digits
124	n/a	digits = '000000123456789'
125	n/a	signs = ('+', '-', '')
126	n/a
127	n/a	# put together random short valid strings
128	n/a	# \d[.\d]?e
129	n/a	for i in range(1000):
130	n/a	for j in range(TEST_SIZE):
131	n/a	s = random.choice(signs)
132	n/a	intpart_len = random.randrange(5)
133	n/a	s += ''.join(random.choice(digits) for _ in range(intpart_len))
134	n/a	if random.choice([True, False]):
135	n/a	s += '.'
136	n/a	fracpart_len = random.randrange(5)
137	n/a	s += ''.join(random.choice(digits)
138	n/a	for _ in range(fracpart_len))
139	n/a	else:
140	n/a	fracpart_len = 0
141	n/a	if random.choice([True, False]):
142	n/a	s += random.choice(['e', 'E'])
143	n/a	s += random.choice(signs)
144	n/a	exponent_len = random.randrange(1, 4)
145	n/a	s += ''.join(random.choice(digits)
146	n/a	for _ in range(exponent_len))
147	n/a
148	n/a	if intpart_len + fracpart_len:
149	n/a	yield s
150	n/a
151	n/a	test_particular = [
152	n/a	# squares
153	n/a	'1.00000000100000000025',
154	n/a	'1.0000000000000000000000000100000000000000000000000' #...
155	n/a	'00025',
156	n/a	'1.0000000000000000000000000000000000000000000010000' #...
157	n/a	'0000000000000000000000000000000000000000025',
158	n/a	'1.0000000000000000000000000000000000000000000000000' #...
159	n/a	'000001000000000000000000000000000000000000000000000' #...
160	n/a	'000000000025',
161	n/a	'0.99999999900000000025',
162	n/a	'0.9999999999999999999999999999999999999999999999999' #...
163	n/a	'999000000000000000000000000000000000000000000000000' #...
164	n/a	'000025',
165	n/a	'0.9999999999999999999999999999999999999999999999999' #...
166	n/a	'999999999999999999999999999999999999999999999999999' #...
167	n/a	'999999999999999999999999999999999999999990000000000' #...
168	n/a	'000000000000000000000000000000000000000000000000000' #...
169	n/a	'000000000000000000000000000000000000000000000000000' #...
170	n/a	'0000000000000000000000000000025',
171	n/a
172	n/a	'1.0000000000000000000000000000000000000000000000000' #...
173	n/a	'000000000000000000000000000000000000000000000000000' #...
174	n/a	'100000000000000000000000000000000000000000000000000' #...
175	n/a	'000000000000000000000000000000000000000000000000001',
176	n/a	'1.0000000000000000000000000000000000000000000000000' #...
177	n/a	'000000000000000000000000000000000000000000000000000' #...
178	n/a	'500000000000000000000000000000000000000000000000000' #...
179	n/a	'000000000000000000000000000000000000000000000000005',
180	n/a	'1.0000000000000000000000000000000000000000000000000' #...
181	n/a	'000000000100000000000000000000000000000000000000000' #...
182	n/a	'000000000000000000250000000000000002000000000000000' #...
183	n/a	'000000000000000000000000000000000000000000010000000' #...
184	n/a	'000000000000000000000000000000000000000000000000000' #...
185	n/a	'0000000000000000001',
186	n/a	'1.0000000000000000000000000000000000000000000000000' #...
187	n/a	'000000000100000000000000000000000000000000000000000' #...
188	n/a	'000000000000000000249999999999999999999999999999999' #...
189	n/a	'999999999999979999999999999999999999999999999999999' #...
190	n/a	'999999999999999999999900000000000000000000000000000' #...
191	n/a	'000000000000000000000000000000000000000000000000000' #...
192	n/a	'00000000000000000000000001',
193	n/a
194	n/a	'0.9999999999999999999999999999999999999999999999999' #...
195	n/a	'999999999900000000000000000000000000000000000000000' #...
196	n/a	'000000000000000000249999999999999998000000000000000' #...
197	n/a	'000000000000000000000000000000000000000000010000000' #...
198	n/a	'000000000000000000000000000000000000000000000000000' #...
199	n/a	'0000000000000000001',
200	n/a	'0.9999999999999999999999999999999999999999999999999' #...
201	n/a	'999999999900000000000000000000000000000000000000000' #...
202	n/a	'000000000000000000250000001999999999999999999999999' #...
203	n/a	'999999999999999999999999999999999990000000000000000' #...
204	n/a	'000000000000000000000000000000000000000000000000000' #...
205	n/a	'1',
206	n/a
207	n/a	# tough cases for ln etc.
208	n/a	'1.000000000000000000000000000000000000000000000000' #...
209	n/a	'00000000000000000000000000000000000000000000000000' #...
210	n/a	'00100000000000000000000000000000000000000000000000' #...
211	n/a	'00000000000000000000000000000000000000000000000000' #...
212	n/a	'0001',
213	n/a	'0.999999999999999999999999999999999999999999999999' #...
214	n/a	'99999999999999999999999999999999999999999999999999' #...
215	n/a	'99899999999999999999999999999999999999999999999999' #...
216	n/a	'99999999999999999999999999999999999999999999999999' #...
217	n/a	'99999999999999999999999999999999999999999999999999' #...
218	n/a	'9999'
219	n/a	]
220	n/a
221	n/a
222	n/a	TESTCASES = [
223	n/a	[x for x in test_short_halfway_cases()],
224	n/a	[x for x in test_halfway_cases()],
225	n/a	[x for x in test_boundaries()],
226	n/a	[x for x in test_underflow_boundary()],
227	n/a	[x for x in test_bigcomp()],
228	n/a	[x for x in test_parsing()],
229	n/a	test_particular
230	n/a	]
231	n/a
232	n/a	def un_randfloat():
233	n/a	for i in range(1000):
234	n/a	l = random.choice(TESTCASES[:6])
235	n/a	yield random.choice(l)
236	n/a	for v in test_particular:
237	n/a	yield v
238	n/a
239	n/a	def bin_randfloat():
240	n/a	for i in range(1000):
241	n/a	l1 = random.choice(TESTCASES)
242	n/a	l2 = random.choice(TESTCASES)
243	n/a	yield random.choice(l1), random.choice(l2)
244	n/a
245	n/a	def tern_randfloat():
246	n/a	for i in range(1000):
247	n/a	l1 = random.choice(TESTCASES)
248	n/a	l2 = random.choice(TESTCASES)
249	n/a	l3 = random.choice(TESTCASES)
250	n/a	yield random.choice(l1), random.choice(l2), random.choice(l3)