[mirror_edk2.git] / AppPkg / Applications / Python / Python-2.7.2 / Lib / test / double_const.py

from test.test_support import TestFailed\r
\r
# A test for SF bug 422177:  manifest float constants varied way too much in\r
# precision depending on whether Python was loading a module for the first\r
# time, or reloading it from a precompiled .pyc.  The "expected" failure\r
# mode is that when test_import imports this after all .pyc files have been\r
# erased, it passes, but when test_import imports this from\r
# double_const.pyc, it fails.  This indicates a woeful loss of precision in\r
# the marshal format for doubles.  It's also possible that repr() doesn't\r
# produce enough digits to get reasonable precision for this box.\r
\r
PI    = 3.14159265358979324\r
TWOPI = 6.28318530717958648\r
\r
PI_str    = "3.14159265358979324"\r
TWOPI_str = "6.28318530717958648"\r
\r
# Verify that the double x is within a few bits of eval(x_str).\r
def check_ok(x, x_str):\r
    assert x > 0.0\r
    x2 = eval(x_str)\r
    assert x2 > 0.0\r
    diff = abs(x - x2)\r
    # If diff is no larger than 3 ULP (wrt x2), then diff/8 is no larger\r
    # than 0.375 ULP, so adding diff/8 to x2 should have no effect.\r
    if x2 + (diff / 8.) != x2:\r
        raise TestFailed("Manifest const %s lost too much precision " % x_str)\r
\r
check_ok(PI, PI_str)\r
check_ok(TWOPI, TWOPI_str)\r
Commit	Line	Data
4710c53d	1	from test.test_support import TestFailed\r
	2	\r
	3	# A test for SF bug 422177: manifest float constants varied way too much in\r
	4	# precision depending on whether Python was loading a module for the first\r
	5	# time, or reloading it from a precompiled .pyc. The "expected" failure\r
	6	# mode is that when test_import imports this after all .pyc files have been\r
	7	# erased, it passes, but when test_import imports this from\r
	8	# double_const.pyc, it fails. This indicates a woeful loss of precision in\r
	9	# the marshal format for doubles. It's also possible that repr() doesn't\r
	10	# produce enough digits to get reasonable precision for this box.\r
	11	\r
	12	PI = 3.14159265358979324\r
	13	TWOPI = 6.28318530717958648\r
	14	\r
	15	PI_str = "3.14159265358979324"\r
	16	TWOPI_str = "6.28318530717958648"\r
	17	\r
	18	# Verify that the double x is within a few bits of eval(x_str).\r
	19	def check_ok(x, x_str):\r
	20	assert x > 0.0\r
	21	x2 = eval(x_str)\r
	22	assert x2 > 0.0\r
	23	diff = abs(x - x2)\r
	24	# If diff is no larger than 3 ULP (wrt x2), then diff/8 is no larger\r
	25	# than 0.375 ULP, so adding diff/8 to x2 should have no effect.\r
	26	if x2 + (diff / 8.) != x2:\r
	27	raise TestFailed("Manifest const %s lost too much precision " % x_str)\r
	28	\r
	29	check_ok(PI, PI_str)\r
	30	check_ok(TWOPI, TWOPI_str)\r