Mercurial > cpython-lru_cache-weakref
view Lib/test/test_setcomps.py @ 87690:66c1c9f32567 default tip
Add use_weakref option to functools.lru_cache
The use_weakref option makes lru_cache create weak references to the function
arguments when creating the cache key, which prevents them from staying in the
memory forever even after all other references to them are gone.
This is a proof of concept for http://bugs.python.org/issue19859
| author | Radomir Dopieralski <devel@sheep.art.pl> |
|---|---|
| date | Tue, 03 Dec 2013 16:02:48 +0100 |
| parents | 9c930a32cebb |
| children |
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doctests = """ ########### Tests mostly copied from test_listcomps.py ############ Test simple loop with conditional >>> sum({i*i for i in range(100) if i&1 == 1}) 166650 Test simple case >>> {2*y + x + 1 for x in (0,) for y in (1,)} {3} Test simple nesting >>> list(sorted({(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(sorted({(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 Verify that syntax error's are raised for setcomps used as lvalues >>> {y for y in (1,2)} = 10 # doctest: +IGNORE_EXCEPTION_DETAIL Traceback (most recent call last): ... SyntaxError: ... >>> {y for y in (1,2)} += 10 # doctest: +IGNORE_EXCEPTION_DETAIL Traceback (most recent call last): ... SyntaxError: ... Make a nested set comprehension that acts like set(range()) >>> def srange(n): ... return {i for i in range(n)} >>> list(sorted(srange(10))) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Same again, only as a lambda expression instead of a function definition >>> lrange = lambda n: {i for i in range(n)} >>> list(sorted(lrange(10))) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Generators can call other generators: >>> def grange(n): ... for x in {i for i in range(n)}: ... yield x >>> list(sorted(grange(5))) [0, 1, 2, 3, 4] Make sure that None is a valid return value >>> {None for i in range(10)} {None} ########### Tests for various scoping corner cases ############ Return lambdas that use the iteration variable as a default argument >>> items = {(lambda i=i: i) for i in range(5)} >>> {x() for x in items} == set(range(5)) True Same again, only this time as a closure variable >>> items = {(lambda: i) for i in range(5)} >>> {x() for x in items} {4} Another way to test that the iteration variable is local to the list comp >>> items = {(lambda: i) for i in range(5)} >>> i = 20 >>> {x() for x in items} {4} And confirm that a closure can jump over the list comp scope >>> items = {(lambda: y) for i in range(5)} >>> y = 2 >>> {x() for x in items} {2} We also repeat each of the above scoping tests inside a function >>> def test_func(): ... items = {(lambda i=i: i) for i in range(5)} ... return {x() for x in items} >>> test_func() == set(range(5)) True >>> def test_func(): ... items = {(lambda: i) for i in range(5)} ... return {x() for x in items} >>> test_func() {4} >>> def test_func(): ... items = {(lambda: i) for i in range(5)} ... i = 20 ... return {x() for x in items} >>> test_func() {4} >>> def test_func(): ... items = {(lambda: y) for i in range(5)} ... y = 2 ... return {x() for x in items} >>> test_func() {2} """ __test__ = {'doctests' : doctests} def test_main(verbose=None): import sys from test import support from test import test_setcomps support.run_doctest(test_setcomps, verbose) # verify reference counting if verbose and hasattr(sys, "gettotalrefcount"): import gc counts = [None] * 5 for i in range(len(counts)): support.run_doctest(test_setcomps, verbose) gc.collect() counts[i] = sys.gettotalrefcount() print(counts) if __name__ == "__main__": test_main(verbose=True)
