def test_deferred_callback_returns_another_deferred():
d = Deferred()
d2 = Deferred()
d.add_callback(lambda r: succeed(r + 5).add_callback(lambda v: v + 5))
d.add_callback(lambda r: d2)
d.callback(5)
assert d.result is d2
assert d.paused
assert d.called
d2.callback(7)
assert d.result == 7
assert d2.result == 7
def test_deferred_list_fails():
d1 = Deferred()
d2 = Deferred()
d3 = Deferred()
dl = DeferredList([1, succeed(2), d1, d2, d3])
assert not dl.called
e1 = Exception('d1 failed')
d1.errback(e1)
d2.errback(Exception('d2 failed'))
d3.callback('hello')
assert dl.called
assert isinstance(dl.result, DeferredException)
assert dl.result.value == e1
def test_deferred_exception_catch():
def dummy_errback(deferred_exception):
deferred_exception.catch(OSError)
return "caught"
deferred = Deferred()
deferred.add_errback(dummy_errback)
deferred.errback(OSError())
assert deferred.result == 'caught'
def test_errback():
holder = []
d = Deferred()
e = Exception('errback test')
d.add_errback(lambda e: holder.append(e))
d.errback(e)
assert isinstance(holder[0], DeferredException)
assert holder[0].value == e
def test_callback_resolution():
d = Deferred()
d.add_callback(lambda r: fail(Exception(r + "b")))
d.add_errback(lambda e: e.value.args[0] + "c")
d.add_callbacks(lambda r: r + "d", lambda e: e.value.args[0] + 'f')
d.callback("a")
assert d.result == "abcd"
def run_resolve_fn(resolver, original_resolver):
result = resolver()
if isinstance(result, Future) or iscoroutine(result):
future = gen.convert_yielded(result)
d = Deferred()
IOLoop.current().add_future(future, process_future_result(d))
return d
# Si no es future ni corutina
return result
def test_deferred_dict():
d = Deferred()
dd = DeferredDict({'a': 1, 'b': d})
assert not dd.called
d.callback(2)
assert dd.called
assert dd.result == {'a': 1, 'b': 2}
def test_deferred_list():
d = Deferred()
dl = DeferredList([1, d])
assert not dl.called
d.callback(2)
assert dl.called
assert dl.result == [1, 2]
def test_callback_var_args():
holder = []
d = Deferred()
d.add_callback(lambda *args, **kwargs: holder.append((args, kwargs)),
2,
3,
a=4,
b=5)
d.callback(1)
assert holder[0] == ((1, 2, 3), {'a': 4, 'b': 5})
def test_errback_chain():
holder = []
d = Deferred()
e = Exception('a')
d.add_callbacks(holder.append, lambda e: Exception(e.value.args[0] + 'b'))
d.add_callbacks(holder.append, lambda e: Exception(e.value.args[0] + 'c'))
d.errback(e)
assert d.result.value.args[0] == 'abc'
assert len(holder) == 0
def test_callback_raises_exception():
def callback(val):
raise AttributeError(val)
d = Deferred()
d.add_callback(callback)
d.callback('test')
assert isinstance(d.result, DeferredException)
assert isinstance(d.result.value, AttributeError)
assert d.result.value.args[0] == "test"
def test_callback_resolution_weaving():
d = Deferred()
d.add_callbacks(lambda r: fail(Exception(r + "b")),
lambda e: e.value.args[0] + 'w')
d.add_callbacks(lambda e: Exception(e + "x"),
lambda e: e.value.args[0] + "c")
d.add_callbacks(lambda r: Exception(r + "d"),
lambda e: e.value.args[0] + 'y')
d.add_callbacks(lambda r: r + "z", lambda e: e.value.args[0] + 'e')
d.callback("a")
assert d.result == "abcde"
def test_callback_resolution_weaving_2():
d = Deferred()
d.add_callbacks(lambda r: fail(Exception(r + "b")),
lambda e: e.value.args[0] + 'w')
d.add_callbacks(lambda e: Exception(e + "x"),
lambda e: e.value.args[0] + "c")
d.add_callbacks(lambda r: Exception(r + "d"),
lambda e: e.value.args[0] + 'y')
d.add_callbacks(lambda r: fail(ValueError(r + "z")),
lambda e: e.value.args[0] + 'e')
d.errback(Exception('v'))
assert isinstance(d.result, DeferredException)
assert isinstance(d.result.value, ValueError)
assert d.result.value.args[0] == "vwxyz"
def test_callbacks_and_errbacks_return_original_deferred():
d = Deferred()
assert d.add_callback(lambda a: None) is d
assert d.add_errback(lambda a: None) is d
assert d.add_callbacks(lambda a: None, lambda a: None) is d
def test_cant_errback_twice():
d1 = Deferred()
d1.errback(Exception('hello'))
with raises(AlreadyCalledDeferred):
d1.errback(Exception('world'))
def test_cant_callback_twice():
d1 = Deferred()
d1.callback('hello')
with raises(AlreadyCalledDeferred):
d1.callback('world')
