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import dis
import sys
from cStringIO import StringIO
import unittest
def disassemble(func):
f = StringIO()
tmp = sys.stdout
sys.stdout = f
dis.dis(func)
sys.stdout = tmp
result = f.getvalue()
f.close()
return result
def dis_single(line):
return disassemble(compile(line, '', 'single'))
class TestTranforms(unittest.TestCase):
def test_unot(self):
# UNARY_NOT JUMP_IF_FALSE POP_TOP --> JUMP_IF_TRUE POP_TOP'
def unot(x):
if not x == 2:
del x
asm = disassemble(unot)
for elem in ('UNARY_NOT', 'JUMP_IF_FALSE'):
self.assert_(elem not in asm)
for elem in ('JUMP_IF_TRUE', 'POP_TOP'):
self.assert_(elem in asm)
def test_elim_inversion_of_is_or_in(self):
for line, elem in (
('not a is b', '(is not)',),
('not a in b', '(not in)',),
('not a is not b', '(is)',),
('not a not in b', '(in)',),
):
asm = dis_single(line)
self.assert_(elem in asm)
def test_none_as_constant(self):
# LOAD_GLOBAL None --> LOAD_CONST None
def f(x):
None
return x
asm = disassemble(f)
for elem in ('LOAD_GLOBAL',):
self.assert_(elem not in asm)
for elem in ('LOAD_CONST', '(None)'):
self.assert_(elem in asm)
def test_while_one(self):
# Skip over: LOAD_CONST trueconst JUMP_IF_FALSE xx POP_TOP
def f():
while 1:
pass
return list
asm = disassemble(f)
for elem in ('LOAD_CONST', 'JUMP_IF_FALSE'):
self.assert_(elem not in asm)
for elem in ('JUMP_ABSOLUTE',):
self.assert_(elem in asm)
def test_pack_unpack(self):
for line, elem in (
('a, = a,', 'LOAD_CONST',),
('a, b = a, b', 'ROT_TWO',),
('a, b, c = a, b, c', 'ROT_THREE',),
):
asm = dis_single(line)
self.assert_(elem in asm)
self.assert_('BUILD_TUPLE' not in asm)
self.assert_('UNPACK_TUPLE' not in asm)
def test_folding_of_tuples_of_constants(self):
for line, elem in (
('a = 1,2,3', '((1, 2, 3))',),
('("a","b","c")', "(('a', 'b', 'c'))",),
('a,b,c = 1,2,3', '((1, 2, 3))',),
):
asm = dis_single(line)
self.assert_(elem in asm)
self.assert_('BUILD_TUPLE' not in asm)
def test_elim_extra_return(self):
# RETURN LOAD_CONST None RETURN --> RETURN
def f(x):
return x
asm = disassemble(f)
self.assert_('LOAD_CONST' not in asm)
self.assert_('(None)' not in asm)
self.assertEqual(asm.split().count('RETURN_VALUE'), 1)
def test_main(verbose=None):
import sys
from test import test_support
test_classes = (TestTranforms,)
test_support.run_unittest(*test_classes)
# verify reference counting
if verbose and hasattr(sys, "gettotalrefcount"):
import gc
counts = [None] * 5
for i in xrange(len(counts)):
test_support.run_unittest(*test_classes)
gc.collect()
counts[i] = sys.gettotalrefcount()
print counts
if __name__ == "__main__":
test_main(verbose=True)
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