cpython/Lib/test/test_unpack_ex.py

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Merged revisions 55225-55227,55229-55269 via svnmerge from svn+ssh://pythondev@svn.python.org/python/branches/p3yk ................ r55238 | guido.van.rossum | 2007-05-10 16:46:05 -0700 (Thu, 10 May 2007) | 9 lines Merged revisions 55227 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r55227 | guido.van.rossum | 2007-05-10 10:20:15 -0700 (Thu, 10 May 2007) | 2 lines Fix a bug in test_c_api() that caused a negative refcount. ........ ................ r55246 | neal.norwitz | 2007-05-11 00:01:52 -0700 (Fri, 11 May 2007) | 1 line Remove commands.getstatus() it is obsolete. ................ r55248 | neal.norwitz | 2007-05-11 00:29:05 -0700 (Fri, 11 May 2007) | 2 lines Remove bsddb185 support. ................ r55249 | neal.norwitz | 2007-05-11 00:29:50 -0700 (Fri, 11 May 2007) | 1 line Remove bsddb185 module too ................ r55250 | neal.norwitz | 2007-05-11 00:32:13 -0700 (Fri, 11 May 2007) | 1 line bsddb185: Gotta remove from the file checked in, not Setup ................ r55251 | neal.norwitz | 2007-05-11 00:53:26 -0700 (Fri, 11 May 2007) | 1 line Remove obsolete IRIX modules (as much as I could find, there is probably more) ................ r55252 | neal.norwitz | 2007-05-11 00:55:35 -0700 (Fri, 11 May 2007) | 1 line Remove SGI turd. ................ r55254 | georg.brandl | 2007-05-11 03:11:01 -0700 (Fri, 11 May 2007) | 2 lines Add a case for set comprehensions to the "cannot assign to" switch. ................ r55255 | georg.brandl | 2007-05-11 03:11:25 -0700 (Fri, 11 May 2007) | 2 lines Fix wrong imports. ................ r55261 | georg.brandl | 2007-05-11 07:37:48 -0700 (Fri, 11 May 2007) | 2 lines Remove removed tex files. ................ r55262 | georg.brandl | 2007-05-11 08:28:41 -0700 (Fri, 11 May 2007) | 2 lines Commit PEP 3132 implementation. ................ r55264 | georg.brandl | 2007-05-11 08:50:19 -0700 (Fri, 11 May 2007) | 2 lines Check in the inevitable AST version number and format Py_ssize_t with %zd. ................ r55265 | neal.norwitz | 2007-05-11 09:12:22 -0700 (Fri, 11 May 2007) | 1 line Remove mention of os.popen* and popen2.* since these will be removed. ................ r55266 | neal.norwitz | 2007-05-11 09:19:57 -0700 (Fri, 11 May 2007) | 1 line Get doc to build again (almost, the doc is fine) ................ r55267 | neal.norwitz | 2007-05-11 09:21:02 -0700 (Fri, 11 May 2007) | 1 line Really get doc to build (remove use of string module) ................ r55269 | neal.norwitz | 2007-05-11 09:29:43 -0700 (Fri, 11 May 2007) | 1 line Add some notes to cleanup later ................
2007-05-11 13:50:42 -03:00
# Tests for extended unpacking, starred expressions.
doctests = """
Unpack tuple
>>> t = (1, 2, 3)
>>> a, *b, c = t
>>> a == 1 and b == [2] and c == 3
True
Unpack list
>>> l = [4, 5, 6]
>>> a, *b = l
>>> a == 4 and b == [5, 6]
True
Unpack implied tuple
>>> *a, = 7, 8, 9
>>> a == [7, 8, 9]
True
Unpack string... fun!
>>> a, *b = 'one'
>>> a == 'o' and b == ['n', 'e']
True
Unpack long sequence
>>> a, b, c, *d, e, f, g = range(10)
>>> (a, b, c, d, e, f, g) == (0, 1, 2, [3, 4, 5, 6], 7, 8, 9)
True
Unpack short sequence
>>> a, *b, c = (1, 2)
>>> a == 1 and c == 2 and b == []
True
Unpack generic sequence
>>> class Seq:
... def __getitem__(self, i):
... if i >= 0 and i < 3: return i
... raise IndexError
...
>>> a, *b = Seq()
>>> a == 0 and b == [1, 2]
True
Unpack in for statement
>>> for a, *b, c in [(1,2,3), (4,5,6,7)]:
... print(a, b, c)
...
1 [2] 3
4 [5, 6] 7
Unpack in list
>>> [a, *b, c] = range(5)
>>> a == 0 and b == [1, 2, 3] and c == 4
True
Multiple targets
>>> a, *b, c = *d, e = range(5)
>>> a == 0 and b == [1, 2, 3] and c == 4 and d == [0, 1, 2, 3] and e == 4
True
Now for some failures
Unpacking non-sequence
>>> a, *b = 7
Traceback (most recent call last):
...
TypeError: 'int' object is not iterable
Unpacking sequence too short
>>> a, *b, c, d, e = Seq()
Traceback (most recent call last):
...
ValueError: need more than 3 values to unpack
Unpacking a sequence where the test for too long raises a different kind of
error
>>> class BozoError(Exception):
... pass
...
>>> class BadSeq:
... def __getitem__(self, i):
... if i >= 0 and i < 3:
... return i
... elif i == 3:
... raise BozoError
... else:
... raise IndexError
...
Trigger code while not expecting an IndexError (unpack sequence too long, wrong
error)
>>> a, *b, c, d, e = BadSeq()
Traceback (most recent call last):
...
test.test_unpack_ex.BozoError
Now some general starred expressions (all fail).
>>> a, *b, c, *d, e = range(10) # doctest:+ELLIPSIS
Traceback (most recent call last):
...
SyntaxError: two starred expressions in assignment (...)
>>> [*b, *c] = range(10) # doctest:+ELLIPSIS
Traceback (most recent call last):
...
SyntaxError: two starred expressions in assignment (...)
>>> *a = range(10) # doctest:+ELLIPSIS
Traceback (most recent call last):
...
SyntaxError: starred assignment target must be in a list or tuple (...)
>>> *a # doctest:+ELLIPSIS
Traceback (most recent call last):
...
SyntaxError: can use starred expression only as assignment target (...)
>>> *1 # doctest:+ELLIPSIS
Traceback (most recent call last):
...
SyntaxError: can use starred expression only as assignment target (...)
>>> x = *a # doctest:+ELLIPSIS
Traceback (most recent call last):
...
SyntaxError: can use starred expression only as assignment target (...)
"""
__test__ = {'doctests' : doctests}
def test_main(verbose=False):
import sys
from test import test_support
from test import test_unpack_ex
test_support.run_doctest(test_unpack_ex, verbose)
if __name__ == "__main__":
test_main(verbose=True)