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tests/basics: Add tests for weakref.ref and weakref.finalize.
Signed-off-by: Damien George <damien@micropython.org>
1 parent 74e9457 commit c91d09a

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‎tests/basics/weakref_finalize_basic.py‎

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# Test weakref.finalize() functionality that doesn't require gc.collect().
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try:
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import weakref
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except ImportError:
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print("SKIP")
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raise SystemExit
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# Cannot reference non-heap objects.
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for value in (None, False, True, Ellipsis, 0, "", ()):
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try:
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weakref.finalize(value, lambda: None)
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except TypeError:
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print(value, "TypeError")
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# Convert (obj, func, args, kwargs) so CPython and MicroPython have a chance to match.
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def convert_4_tuple(values):
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if values is None:
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return None
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return (type(values[0]).__name__, type(values[1]), values[2], values[3])
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class A:
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def __str__(self):
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return "<A object>"
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print("test alive, peek, detach")
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a = A()
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f = weakref.finalize(a, lambda: None, 1, 2, kwarg=3)
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print("alive", f.alive)
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print("peek", convert_4_tuple(f.peek()))
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print("detach", convert_4_tuple(f.detach()))
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print("alive", f.alive)
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print("peek", convert_4_tuple(f.peek()))
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print("detach", convert_4_tuple(f.detach()))
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print("call", f())
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a = None
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print("test alive, peek, call")
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a = A()
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f = weakref.finalize(a, lambda *args, **kwargs: (args, kwargs), 1, 2, kwarg=3)
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print("alive", f.alive)
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print("peek", convert_4_tuple(f.peek()))
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print("call", f())
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print("alive", f.alive)
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print("peek", convert_4_tuple(f.peek()))
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print("call", f())
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print("detach", convert_4_tuple(f.detach()))
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print("test call which raises exception")
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a = A()
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f = weakref.finalize(a, lambda: 1 / 0)
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try:
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f()
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except ZeroDivisionError as er:
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print("call ZeroDivisionError")

‎tests/basics/weakref_finalize_collect.py‎

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# Test weakref.finalize() functionality requiring gc.collect().
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try:
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import weakref
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except ImportError:
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print("SKIP")
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raise SystemExit
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# gc module must be available if weakref is.
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import gc
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class A:
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def __str__(self):
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return "<A object>"
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def callback(*args, **kwargs):
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print("callback({}, {})".format(args, kwargs))
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return 42
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def test():
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print("test basic use of finalize() with a simple callback")
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a = A()
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f = weakref.finalize(a, callback)
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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print("alive", f.alive)
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print("peek", f.peek())
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print("detach", f.detach())
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print("call", f())
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print("test that a callback is passed the correct values")
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a = A()
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f = weakref.finalize(a, callback, 1, 2, kwarg=3)
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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print("alive", f.alive)
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print("peek", f.peek())
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print("detach", f.detach())
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print("call", f())
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print("test that calling the finalizer cancels the finalizer")
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a = A()
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f = weakref.finalize(a, callback)
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print(f())
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print(a)
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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print("test that calling detach cancels the finalizer")
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a = A()
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f = weakref.finalize(a, callback)
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print(len(f.detach()))
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print(a)
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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print("test that finalize does not get collected before its ref does")
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a = A()
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weakref.finalize(a, callback)
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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print("free a")
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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test()

‎tests/basics/weakref_multiple_refs.py‎

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# Test weakref when multiple weak references are active.
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#
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# This test has different output to CPython due to the order that MicroPython
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# executes weak reference callbacks.
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try:
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import weakref
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except ImportError:
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print("SKIP")
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raise SystemExit
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# gc module must be available if weakref is.
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import gc
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class A:
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def __str__(self):
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return "<A object>"
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def test():
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print("test having multiple ref and finalize objects referencing the same thing")
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a = A()
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r1 = weakref.ref(a, lambda r: print("ref1", r()))
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f1 = weakref.finalize(a, lambda: print("finalize1"))
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r2 = weakref.ref(a, lambda r: print("ref2", r()))
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f2 = weakref.finalize(a, lambda: print("finalize2"))
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print(r1(), f1.alive, r2(), f2.alive)
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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test()

‎tests/basics/weakref_multiple_refs.py.exp‎

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test having multiple ref and finalize objects referencing the same thing
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<A object> True <A object> True
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finalize2
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finalize1
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ref2 None
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ref1 None

‎tests/basics/weakref_ref_basic.py‎

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# Test weakref.ref() functionality that doesn't require gc.collect().
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try:
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import weakref
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except ImportError:
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print("SKIP")
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raise SystemExit
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# Cannot reference non-heap objects.
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for value in (None, False, True, Ellipsis, 0, "", ()):
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try:
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weakref.ref(value)
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except TypeError:
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print(value, "TypeError")

‎tests/basics/weakref_ref_collect.py‎

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# Test weakref.ref() functionality requiring gc.collect().
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try:
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import weakref
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except ImportError:
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print("SKIP")
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raise SystemExit
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# gc module must be available if weakref is.
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import gc
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# Cannot reference non-heap objects.
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for value in (None, False, True, Ellipsis, 0, "", ()):
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try:
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weakref.ref(value)
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except TypeError:
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print(value, "TypeError")
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class A:
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def __str__(self):
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return "<A object>"
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def callback(r):
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print("callback", r())
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def test():
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print("test basic use of ref() with only one argument")
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a = A()
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r = weakref.ref(a)
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print(r())
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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print(r())
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print("test use of ref() with a callback")
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a = A()
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r = weakref.ref(a, callback)
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print(r())
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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print(r())
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print("test when weakref gets collected before the object it refs")
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a = A()
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r = weakref.ref(a, callback)
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print(r())
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r = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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a = None
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print("test a double reference")
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a = A()
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r1 = weakref.ref(a, callback)
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r2 = weakref.ref(a, callback)
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print(r1(), r2())
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a = None
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clean_the_stack = [0, 0, 0, 0]
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gc.collect()
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print(r1(), r2())
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test()

‎tests/run-tests.py‎

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"webassembly": (
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"basics/string_format_modulo.py", # can't print nulls to stdout
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"basics/string_strip.py", # can't print nulls to stdout
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"basics/weakref_ref_collect.py", # requires custom test due to GC behaviour
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"basics/weakref_finalize_collect.py", # requires custom test due to GC behaviour
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"extmod/asyncio_basic2.py",
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"extmod/asyncio_cancel_self.py",
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"extmod/asyncio_current_task.py",

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