cpython/Lib/test/test_parser.py

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import os.path
import parser
import pprint
import sys
from parser import expr, suite, sequence2ast
from test_support import verbose
#
# First, we test that we can generate trees from valid source fragments,
# and that these valid trees are indeed allowed by the tree-loading side
# of the parser module.
#
def roundtrip(f, s):
st1 = f(s)
t = st1.totuple()
st2 = parser.sequence2ast(t)
def roundtrip_fromfile(filename):
roundtrip(suite, open(filename).read())
def test_expr(s):
print "expr:", s
roundtrip(expr, s)
def test_suite(s):
print "suite:", s
roundtrip(suite, s)
print "Expressions:"
test_expr("foo(1)")
test_expr("[1, 2, 3]")
test_expr("[x**3 for x in range(20)]")
test_expr("[x**3 for x in range(20) if x % 3]")
test_expr("foo(*args)")
test_expr("foo(*args, **kw)")
test_expr("foo(**kw)")
test_expr("foo(key=value)")
test_expr("foo(key=value, *args)")
test_expr("foo(key=value, *args, **kw)")
test_expr("foo(key=value, **kw)")
test_expr("foo(a, b, c, *args)")
test_expr("foo(a, b, c, *args, **kw)")
test_expr("foo(a, b, c, **kw)")
test_expr("foo + bar")
print
print "Statements:"
test_suite("print")
test_suite("print 1")
test_suite("print 1,")
test_suite("print >>fp")
test_suite("print >>fp, 1")
test_suite("print >>fp, 1,")
# expr_stmt
test_suite("a")
test_suite("a = b")
test_suite("a = b = c = d = e")
test_suite("a += b")
test_suite("a -= b")
test_suite("a *= b")
test_suite("a /= b")
test_suite("a %= b")
test_suite("a &= b")
test_suite("a |= b")
test_suite("a ^= b")
test_suite("a <<= b")
test_suite("a >>= b")
test_suite("a **= b")
#d = os.path.dirname(os.__file__)
#roundtrip_fromfile(os.path.join(d, "os.py"))
#roundtrip_fromfile(os.path.join(d, "test", "test_parser.py"))
#
# Second, we take *invalid* trees and make sure we get ParserError
# rejections for them.
#
print
print "Invalid parse trees:"
def check_bad_tree(tree, label):
print
print label
try:
sequence2ast(tree)
except parser.ParserError:
print "caught expected exception for invalid tree"
pass
else:
print "test failed: did not properly detect invalid tree:"
pprint.pprint(tree)
# not even remotely valid:
check_bad_tree((1, 2, 3), "<junk>")
# print >>fp,
tree = \
(257,
(264,
(265,
(266,
(268,
(1, 'print'),
(35, '>>'),
(290,
(291,
(292,
(293,
(295,
(296,
(297,
(298, (299, (300, (301, (302, (303, (1, 'fp')))))))))))))),
(12, ','))),
(4, ''))),
(0, ''))
check_bad_tree(tree, "print >>fp,")
# a,,c
tree = \
(258,
(311,
(290,
(291,
(292,
(293,
(295,
(296, (297, (298, (299, (300, (301, (302, (303, (1, 'a')))))))))))))),
(12, ','),
(12, ','),
(290,
(291,
(292,
(293,
(295,
(296, (297, (298, (299, (300, (301, (302, (303, (1, 'c'))))))))))))))),
(4, ''),
(0, ''))
check_bad_tree(tree, "a,,c")
# a $= b
tree = \
(257,
(264,
(265,
(266,
(267,
(312,
(291,
(292,
(293,
(294,
(296,
(297,
(298,
(299, (300, (301, (302, (303, (304, (1, 'a'))))))))))))))),
(268, (37, '$=')),
(312,
(291,
(292,
(293,
(294,
(296,
(297,
(298,
(299, (300, (301, (302, (303, (304, (1, 'b'))))))))))))))))),
(4, ''))),
(0, ''))
check_bad_tree(tree, "a $= b")