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- 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)
- Traceback (most recent call last):
- ...
- 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 that the outermost for-expression makes an immediate check
- for iterability
-
- >>> (i for i in 6)
- Traceback (most recent call last):
- File "<pyshell#4>", line 1, in -toplevel-
- (i for i in 6)
- TypeError: iteration over non-sequence
-
- 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
-
- Verify that syntax error's are raised for genexps used as lvalues
-
- >>> (y for y in (1,2)) = 10
- Traceback (most recent call last):
- ...
- SyntaxError: assign to generator expression not possible
-
- >>> (y for y in (1,2)) += 10
- Traceback (most recent call last):
- ...
- SyntaxError: augmented assign to tuple literal or generator expression not possible
-
-
-
- ########### 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)
-