Function check_against_PyObject_RichCompareBool

Lib/test/test_sort.py:284–310

(self, L)

#==============================================================================
def check_against_PyObject_RichCompareBool(self, L):
    ## The idea here is to exploit the fact that unsafe_tuple_compare uses
    ## PyObject_RichCompareBool for the second elements of tuples. So we have,
    ## for (most) L, sorted(L) == [y[1] for y in sorted([(0,x) for x in L])]
    ## This will work as long as __eq__ => not __lt__ for all the objects in L,
    ## which holds for all the types used below.
    ##
    ## Testing this way ensures that the optimized implementation remains consistent
    ## with the naive implementation, even if changes are made to any of the
    ## richcompares.
    ##
    ## This function tests sorting for three lists (it randomly shuffles each one):
    ##                        1. L
    ##                        2. [(x,) for x in L]
    ##                        3. [((x,),) for x in L]

    random.seed(0)
    random.shuffle(L)
    L_1 = L[:]
    L_2 = [(x,) for x in L]
    L_3 = [((x,),) for x in L]
    for L in [L_1, L_2, L_3]:
        optimized = sorted(L)
        reference = [y[1] for y in sorted([(0,x) for x in L])]
        for (opt, ref) in zip(optimized, reference):
            self.assertIs(opt, ref)
            #note: not assertEqual! We want to ensure *identical* behavior.

class TestOptimizedCompares(unittest.TestCase):
    def test_safe_object_compare(self):