def test_separation_of_init_and_enter(self):
a = object()
t = TrackRCFor(a)
c = a
with t:
del c
del a
t.assertDelta(-2)
def test_nested_context_managers(self):
a, b = "vegan spam", "eggs"
with TrackRCFor(a) as outer:
d = dict(buy=a, sell=b)
with TrackRCFor(a, b) as inner:
del d["buy"]
inner.assertDelta(-1, 0)
del d
outer.assertEqualRC()
def test_nesting_by_using_pre_instantiated(self):
a = "Another Python string, given to name \"a\""
inner = TrackRCFor(a)
# "outer" will see "a" decrefed twice, first by the del statement, then
# by deleting "inner" (which itself holds a reference to a).
with TrackRCFor(inner, a) as outer:
with inner:
del a
inner.assertDelta(-1)
del inner
outer.assertDelta(-1, -2)
def test_wrong_arglist_length(self):
a = object()
b = object()
with TrackRCFor(a, b) as t:
pass
with self.assertRaisesRegex(ValueError, "[lL]ength.+mismatch"):
t.assertDelta(0, 0, 0)
def test_reuse_fail(self):
a = object()
with TrackRCFor(a) as t:
pass
with self.assertRaisesRegex(TypeError, "Context expired"):
with t:
pass
def test_assert_before_exiting(self):
a = object()
b = object()
with self.assertRaisesRegex(TypeError, "Context has not finalized"):
with TrackRCFor(a, b) as t:
c = a
t.assertDelta(1, 0)
def test_use_mixed(self):
a = object()
b = object()
c = object()
with TrackRCFor(a, b, c) as t:
a = b
del c
t.assertDelta(Neg, Pos, NonPos)
def test_use_with_number(self):
a = object()
b = object()
c = "spam"
with TrackRCFor(a, b, c) as t:
d = a
b = {c: c}
t.assertDelta(1, Neg, NonNeg)
def test_decrease_refcount_by_del(self):
class K:
pass
cls = K
with TrackRCFor(K) as keeper:
del K
keeper.assertDelta(-1)
def f():
nonlocal k
with TrackRCFor(k) as t:
d = dict(key=k)
# <---
# ^ This is where the context manager exits. It essentially saves
# the context regarding refcounts *before* the name "d" goes out of
# scope as f returns.
return t
def test_attribute(self):
class K:
def __init__(self, other):
self.attr = other
k = K("spam")
with TrackRCFor(k.attr) as t:
del k.attr
t.assertDelta(-1)
def test_nesting_by_self_duplication(self):
a, b = "cucumber", "pepper"
with TrackRCFor(a, b) as f:
d = dict(buy=a, sell=b)
with f() as g:
d.pop("sell")
self.assertIsNot(g, f)
g.assertDelta(0, -1)
del d
f.assertEqualRC()
def test_ref_cycle(self):
a = []
b = []
c = []
with TrackRCFor(a, b, c) as t:
a.append(b)
b.append(c)
c.append(a)
del a, b, c
t.assertEqualRC()
def test_raise_exception(self):
class SomeException(Exception):
pass
def just_raise(arg):
raise SomeException(arg)
k = "An argument"
with TrackRCFor(k, SomeException) as t:
try:
m = just_raise(k)
except SomeException as exc:
pass
t.assertEqualRC()
def test_container(self):
thing = dict.__getitem__
with TrackRCFor(thing) as k:
box = [thing]
k.assertDelta(1)
def test_increase_refcount_by_binding_new_name(self):
thing = 0
with TrackRCFor(thing) as k:
anotherthing = thing
k.assertDelta(1)
def test_empty_body(self):
a = object()
b = object()
with TrackRCFor(a, b) as t:
pass
t.assertEqualRC()
def test_bare_expression_as_statement(self):
thing = "abc"
with TrackRCFor(thing) as k:
thing
k.assertEqualRC()
def test_use_pos(self):
a = object()
with TrackRCFor(a) as t:
b = a
t.assertDelta(Pos)
def test_repeated_args(self):
a = "spam, spam, spam, spam"
with TrackRCFor(a, a, a) as t:
del a
t.assertDelta(-1, -1, -1)
def test_bind_to_context_manager_args(self):
with TrackRCFor([1]) as t:
a = t.args[0]
t.assertDelta(1)
def test_empty_empty(self):
with TrackRCFor() as t:
pass
t.assertEqualRC()
def test_empty_args(self):
with TrackRCFor() as t:
k = 1
t.assertEqualRC()
def test_use_anything(self):
a = object()
b = object()
with TrackRCFor(a, b) as t:
a = b
t.assertDelta(Anything)
def test_use_nonpos(self):
a = object()
with TrackRCFor(a) as t:
del a
t.assertDelta(Neg)
def test_just_one_arg_in_delta_check(self):
a, b, c = "spam", "spammer", "spamming"
with TrackRCFor(a, b, c) as t:
s = (a, b, c)
t.assertDelta(1)
def test_anonymous_expression(self):
with TrackRCFor([1]) as t:
pass
t.assertEqualRC()
def test_bad_assert(self):
a = object()
with self.assertRaises(AssertionError):
with TrackRCFor(a) as t:
del a
t.assertEqualRC()
