[Python-checkins] python/dist/src/Lib/test test_genexps.py, NONE, 1.1 test_deque.py, 1.10, 1.11 test_grammar.py, 1.49, 1.50 test_parser.py, 1.17, 1.18

rhettinger at users.sourceforge.net rhettinger at users.sourceforge.net
Wed May 19 04:20:43 EDT 2004 

Update of /cvsroot/python/python/dist/src/Lib/test
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv9770/Lib/test

Modified Files:
	test_deque.py test_grammar.py test_parser.py 
Added Files:
	test_genexps.py 
Log Message:
SF patch #872326:  Generator expression implementation
(Code contributed by Jiwon Seo.)

The documentation portion of the patch is being re-worked and will be
checked-in soon.  Likewise, PEP 289 will be updated to reflect Guido's
rationale for the design decisions on binding behavior (as described in
in his patch comments and in discussions on python-dev).

The test file, test_genexps.py, is written in doctest format and is
meant to exercise all aspects of the the patch.  Further additions are
welcome from everyone.  Please stress test this new feature as much as
possible before the alpha release.



--- NEW FILE: test_genexps.py ---
doctests = """

Test simple loop with conditional

    >>> sum(i*i for i in range(100) if i&1 == 1)
    166650

Test simple nesting

    >>> list((i,j) for i in range(3) for j in range(4) )
    [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]

Test nesting with the inner expression dependent on the outer

    >>> list((i,j) for i in range(4) for j in range(i) )
    [(1, 0), (2, 0), (2, 1), (3, 0), (3, 1), (3, 2)]

Make sure the induction variable is not exposed

    >>> i = 20
    >>> sum(i*i for i in range(100))
    328350
    >>> i
    20

Test first class

    >>> g = (i*i for i in range(4))
    >>> type(g)
    <type 'generator'>
    >>> list(g)
    [0, 1, 4, 9]

Test direct calls to next()

    >>> g = (i*i for i in range(3))
    >>> g.next()
    0
    >>> g.next()
    1
    >>> g.next()
    4
    >>> g.next()
    Traceback (most recent call last):
      File "<pyshell#21>", line 1, in -toplevel-
        g.next()
    StopIteration

Does it stay stopped?

    >>> g.next()
    Traceback (most recent call last):
      File "<pyshell#21>", line 1, in -toplevel-
        g.next()
    StopIteration
    >>> list(g)
    []

Test running gen when defining function is out of scope

    >>> def f(n):
    ...     return (i*i for i in xrange(n))
    ...
    >>> list(f(10))
    [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

    >>> def f(n):
    ...     return ((i,j) for i in xrange(3) for j in xrange(n))
    ...
    >>> list(f(4))
    [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
    >>> def f(n):
    ...     return ((i,j) for i in xrange(3) for j in xrange(4) if j in xrange(n))
    ...
    >>> list(f(4))
    [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]
    >>> list(f(2))
    [(0, 0), (0, 1), (1, 0), (1, 1), (2, 0), (2, 1)]

#Verify that parenthesis are required in a statement
#>>> def f(n):
#...     return i*i for i in xrange(n)
#...
#SyntaxError: invalid syntax

Verify early binding for the outermost for-expression

    >>> x=10
    >>> g = (i*i for i in range(x))
    >>> x = 5
    >>> list(g)
    [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

Verify late binding for the outermost if-expression

    >>> include = (2,4,6,8)
    >>> g = (i*i for i in range(10) if i in include)
    >>> include = (1,3,5,7,9)
    >>> list(g)
    [1, 9, 25, 49, 81]

Verify late binding for the innermost for-expression

    >>> g = ((i,j) for i in range(3) for j in range(x))
    >>> x = 4
    >>> list(g)
    [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)]

Verify re-use of tuples (a side benefit of using genexps over listcomps)

    >>> tupleids = map(id, ((i,i) for i in xrange(10)))
    >>> max(tupleids) - min(tupleids)
    0



########### Tests borrowed from or inspired by test_generators.py ############

Make a generator that acts like range()

    >>> yrange = lambda n:  (i for i in xrange(n))
    >>> list(yrange(10))
    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Generators always return to the most recent caller:

    >>> def creator():
    ...     r = yrange(5)
    ...     print "creator", r.next()
    ...     return r
    ...
    >>> def caller():
    ...     r = creator()
    ...     for i in r:
    ...             print "caller", i
    ...
    >>> caller()
    creator 0
    caller 1
    caller 2
    caller 3
    caller 4

Generators can call other generators:

    >>> def zrange(n):
    ...     for i in yrange(n):
    ...         yield i
    ...
    >>> list(zrange(5))
    [0, 1, 2, 3, 4]


Verify that a gen exp cannot be resumed while it is actively running:

    >>> g = (me.next() for i in xrange(10))
    >>> me = g
    >>> me.next()
    Traceback (most recent call last):
      File "<pyshell#30>", line 1, in -toplevel-
        me.next()
      File "<pyshell#28>", line 1, in <generator expression>
        g = (me.next() for i in xrange(10))
    ValueError: generator already executing

Verify exception propagation

    >>> g = (10 // i for i in (5, 0, 2))
    >>> g.next()
    2
    >>> g.next()
    Traceback (most recent call last):
      File "<pyshell#37>", line 1, in -toplevel-
        g.next()
      File "<pyshell#35>", line 1, in <generator expression>
        g = (10 // i for i in (5, 0, 2))
    ZeroDivisionError: integer division or modulo by zero
    >>> g.next()
    Traceback (most recent call last):
      File "<pyshell#38>", line 1, in -toplevel-
        g.next()
    StopIteration

Make sure that None is a valid return value

    >>> list(None for i in xrange(10))
    [None, None, None, None, None, None, None, None, None, None]

Check that generator attributes are present

    >>> g = (i*i for i in range(3))
    >>> expected = set(['gi_frame', 'gi_running', 'next'])
    >>> set(attr for attr in dir(g) if not attr.startswith('__')) >= expected
    True

    >>> print g.next.__doc__
    x.next() -> the next value, or raise StopIteration
    >>> import types
    >>> isinstance(g, types.GeneratorType)
    True

Check the __iter__ slot is defined to return self

    >>> iter(g) is g
    True

Verify that the running flag is set properly

    >>> g = (me.gi_running for i in (0,1))
    >>> me = g
    >>> me.gi_running
    0
    >>> me.next()
    1
    >>> me.gi_running
    0

Verify that genexps are weakly referencable

    >>> import weakref
    >>> g = (i*i for i in range(4))
    >>> wr = weakref.ref(g)
    >>> wr() is g
    True
    >>> p = weakref.proxy(g)
    >>> list(p)
    [0, 1, 4, 9]


"""


__test__ = {'doctests' : doctests}

def test_main(verbose=None):
    import sys
    from test import test_support
    from test import test_genexps
    test_support.run_doctest(test_genexps, verbose)

    # verify reference counting
    if verbose and hasattr(sys, "gettotalrefcount"):
        import gc
        counts = [None] * 5
        for i in xrange(len(counts)):
            test_support.run_doctest(test_genexps, verbose)
            gc.collect()
            counts[i] = sys.gettotalrefcount()
        print counts

if __name__ == "__main__":
    test_main(verbose=True)







Index: test_deque.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_deque.py,v
retrieving revision 1.10
retrieving revision 1.11
diff -C2 -d -r1.10 -r1.11
*** test_deque.py	12 May 2004 20:55:56 -0000	1.10
--- test_deque.py	19 May 2004 08:20:08 -0000	1.11
***************
*** 567,571 ****
      # doctests
      from test import test_deque
! #    test_support.run_doctest(test_deque, verbose)
  
  if __name__ == "__main__":
--- 567,571 ----
      # doctests
      from test import test_deque
!     test_support.run_doctest(test_deque, verbose)
  
  if __name__ == "__main__":

Index: test_grammar.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_grammar.py,v
retrieving revision 1.49
retrieving revision 1.50
diff -C2 -d -r1.49 -r1.50
*** test_grammar.py	12 Feb 2004 17:35:11 -0000	1.49
--- test_grammar.py	19 May 2004 08:20:09 -0000	1.50
***************
*** 740,741 ****
--- 740,784 ----
            if sno == sp_sno and pno == sp_pno
  ]
+ 
+ # generator expression tests
+ g = ([x for x in range(10)] for x in range(1))
+ verify(g.next() == [x for x in range(10)])
+ try:
+     g.next()
+     raise TestFailed, 'should produce StopIteration exception'
+ except StopIteration:
+     pass
+ 
+ a = 1
+ try:
+     g = (a for d in a)
+     g.next()
+     raise TestFailed, 'should produce TypeError'
+ except TypeError:
+     pass
+ 
+ verify(list((x, y) for x in 'abcd' for y in 'abcd') == [(x, y) for x in 'abcd' for y in 'abcd'])
+ verify(list((x, y) for x in 'ab' for y in 'xy') == [(x, y) for x in 'ab' for y in 'xy'])
+ 
+ a = [x for x in range(10)]
+ b = (x for x in (y for y in a))
+ verify(sum(b) == sum([x for x in range(10)]))
+ 
+ verify(sum(x**2 for x in range(10)) == sum([x**2 for x in range(10)]))
+ verify(sum(x*x for x in range(10) if x%2) == sum([x*x for x in range(10) if x%2]))
+ verify(sum(x for x in (y for y in range(10))) == sum([x for x in range(10)]))
+ verify(sum(x for x in (y for y in (z for z in range(10)))) == sum([x for x in range(10)]))
+ verify(sum(x for x in [y for y in (z for z in range(10))]) == sum([x for x in range(10)]))
+ verify(sum(x for x in (y for y in (z for z in range(10) if True)) if True) == sum([x for x in range(10)]))
+ verify(sum(x for x in (y for y in (z for z in range(10) if True) if False) if True) == 0)
+ check_syntax("foo(x for x in range(10), 100)")
+ check_syntax("foo(100, x for x in range(10))")
+ 
+ # test for outmost iterable precomputation
+ x = 10; g = (i for i in range(x)); x = 5
+ verify(len(list(g)) == 10)
+ 
+ # This should hold, since we're only precomputing outmost iterable.
+ x = 10; t = False; g = ((i,j) for i in range(x) if t for j in range(x))
+ x = 5; t = True;
+ verify([(i,j) for i in range(10) for j in range(5)] == list(g))

Index: test_parser.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_parser.py,v
retrieving revision 1.17
retrieving revision 1.18
diff -C2 -d -r1.17 -r1.18
*** test_parser.py	1 May 2003 17:45:44 -0000	1.17
--- test_parser.py	19 May 2004 08:20:09 -0000	1.18
***************
*** 68,71 ****
--- 68,73 ----
          self.check_expr("lambda foo=bar, blaz=blat+2, *y, **z: 0")
          self.check_expr("lambda x, *y, **z: 0")
+         self.check_expr("(x for x in range(10))")
+         self.check_expr("foo(x for x in range(10))")
  
      def test_print(self):

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