| 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 that parenthesis are required when used as a keyword argument value |
| |
| >>> dict(a = i for i in xrange(10)) |
| Traceback (most recent call last): |
| ... |
| SyntaxError: invalid syntax |
| |
| Verify that parenthesis are required when used as a keyword argument value |
| |
| >>> dict(a = (i for i in xrange(10))) #doctest: +ELLIPSIS |
| {'a': <generator object <genexpr> at ...>} |
| |
| 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: 'int' object is not iterable |
| |
| 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))) |
| >>> int(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): |
| ... |
| File "<doctest test.test_genexps.__test__.doctests[40]>", line 1 |
| SyntaxError: can't assign to generator expression |
| |
| >>> (y for y in (1,2)) += 10 |
| Traceback (most recent call last): |
| ... |
| File "<doctest test.test_genexps.__test__.doctests[41]>", line 1 |
| SyntaxError: can't assign to generator expression |
| |
| |
| ########### 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 |
| |
| >>> from test.test_support import HAVE_DOCSTRINGS |
| >>> print(g.next.__doc__ if HAVE_DOCSTRINGS else 'x.next() -> the next value, or raise StopIteration') |
| 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) |
