Adding support to replaced_task_nesting in chains allows for overcoming a very specific use case.
Overall, what it does is set all of the tasks of the chain with the correct replaced_task_nesting level, if the canvas is built from a chain that contains a replaced task that is also a chain (in which case the DAG gets broken as two tasks can be each other's parents which this fix allows overcoming).

TODO:
Maybe add some example doc with enhanced explanation although it would require a bit of effort so I'll get to it at a later date.
Added support for replaced_task_nesting in chains. Adding support to replaced_task_nesting in chains allows for overcoming a very specific use case.
Overall, what it does is set all of the tasks of the chain with the correct replaced_task_nesting level, if the canvas is built from a chain that contains a replaced task that is also a chain (in which case the DAG gets broken as two tasks can be each other's parents which this fix allows overcoming).

TODO:
Maybe add some example doc with enhanced explanation although it would require a bit of effort so I'll get to it at a later date.
import socket
import tempfile
from datetime import datetime, timedelta
from unittest.mock import ANY, MagicMock, Mock, patch, sentinel

import pytest
from kombu import Queue
from kombu.exceptions import EncodeError

from celery import Task, group, uuid
from celery.app.task import _reprtask
from celery.canvas import StampingVisitor, signature
from celery.contrib.testing.mocks import ContextMock
from celery.exceptions import Ignore, ImproperlyConfigured, Retry
from celery.result import AsyncResult, EagerResult
from celery.utils.serialization import UnpickleableExceptionWrapper

try:
    from urllib.error import HTTPError
except ImportError:
    from urllib2 import HTTPError


def return_True(*args, **kwargs):
    # Task run functions can't be closures/lambdas, as they're pickled.
    return True


class MockApplyTask(Task):
    abstract = True
    applied = 0

    def run(self, x, y):
        return x * y

    def apply_async(self, *args, **kwargs):
        self.applied += 1


class TaskWithPriority(Task):
    priority = 10


class TaskWithRetry(Task):
    autoretry_for = (TypeError,)
    retry_kwargs = {'max_retries': 5}
    retry_backoff = True
    retry_backoff_max = 700
    retry_jitter = False


class TaskWithRetryButForTypeError(Task):
    autoretry_for = (Exception,)
    dont_autoretry_for = (TypeError,)
    retry_kwargs = {'max_retries': 5}
    retry_backoff = True
    retry_backoff_max = 700
    retry_jitter = False


class TasksCase:

    def setup_method(self):
        self.mytask = self.app.task(shared=False)(return_True)

        @self.app.task(bind=True, count=0, shared=False)
        def increment_counter(self, increment_by=1):
            self.count += increment_by or 1
            return self.count

        self.increment_counter = increment_counter

        @self.app.task(shared=False)
        def raising():
            raise KeyError('foo')

        self.raising = raising

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task(self, arg1, arg2, kwarg=1, max_retries=None, care=True):
            self.iterations += 1
            rmax = self.max_retries if max_retries is None else max_retries

            assert repr(self.request)
            retries = self.request.retries
            if care and retries >= rmax:
                return arg1
            else:
                raise self.retry(countdown=0, max_retries=rmax)

        self.retry_task = retry_task

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_noargs(self, **kwargs):
            self.iterations += 1

            if self.request.retries >= 3:
                return 42
            else:
                raise self.retry(countdown=0)

        self.retry_task_noargs = retry_task_noargs

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_return_without_throw(self, **kwargs):
            self.iterations += 1
            try:
                if self.request.retries >= 3:
                    return 42
                else:
                    raise Exception("random code exception")
            except Exception as exc:
                return self.retry(exc=exc, throw=False)

        self.retry_task_return_without_throw = retry_task_return_without_throw

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_return_with_throw(self, **kwargs):
            self.iterations += 1
            try:
                if self.request.retries >= 3:
                    return 42
                else:
                    raise Exception("random code exception")
            except Exception as exc:
                return self.retry(exc=exc, throw=True)

        self.retry_task_return_with_throw = retry_task_return_with_throw

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False, autoretry_for=(Exception,))
        def retry_task_auto_retry_with_single_new_arg(self, ret=None, **kwargs):
            if ret is None:
                return self.retry(exc=Exception("I have filled now"), args=["test"], kwargs=kwargs)
            else:
                return ret

        self.retry_task_auto_retry_with_single_new_arg = retry_task_auto_retry_with_single_new_arg

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_auto_retry_with_new_args(self, ret=None, place_holder=None, **kwargs):
            if ret is None:
                return self.retry(args=[place_holder, place_holder], kwargs=kwargs)
            else:
                return ret

        self.retry_task_auto_retry_with_new_args = retry_task_auto_retry_with_new_args

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False, autoretry_for=(Exception,))
        def retry_task_auto_retry_exception_with_new_args(self, ret=None, place_holder=None, **kwargs):
            if ret is None:
                return self.retry(exc=Exception("I have filled"), args=[place_holder, place_holder], kwargs=kwargs)
            else:
                return ret

        self.retry_task_auto_retry_exception_with_new_args = retry_task_auto_retry_exception_with_new_args

        @self.app.task(bind=True, max_retries=10, iterations=0, shared=False,
                       autoretry_for=(Exception,))
        def retry_task_max_retries_override(self, **kwargs):
            # Test for #6436
            self.iterations += 1
            if self.iterations == 3:
                # I wanna force fail here cause i have enough
                self.retry(exc=MyCustomException, max_retries=0)
            self.retry(exc=MyCustomException)

        self.retry_task_max_retries_override = retry_task_max_retries_override

        @self.app.task(bind=True, max_retries=0, iterations=0, shared=False,
                       autoretry_for=(Exception,))
        def retry_task_explicit_exception(self, **kwargs):
            # Test for #6436
            self.iterations += 1
            raise MyCustomException()

        self.retry_task_explicit_exception = retry_task_explicit_exception

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_raise_without_throw(self, **kwargs):
            self.iterations += 1
            try:
                if self.request.retries >= 3:
                    return 42
                else:
                    raise Exception("random code exception")
            except Exception as exc:
                raise self.retry(exc=exc, throw=False)

        self.retry_task_raise_without_throw = retry_task_raise_without_throw

        @self.app.task(bind=True, max_retries=3, iterations=0,
                       base=MockApplyTask, shared=False)
        def retry_task_mockapply(self, arg1, arg2, kwarg=1):
            self.iterations += 1

            retries = self.request.retries
            if retries >= 3:
                return arg1
            raise self.retry(countdown=0)

        self.retry_task_mockapply = retry_task_mockapply

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_customexc(self, arg1, arg2, kwarg=1, **kwargs):
            self.iterations += 1

            retries = self.request.retries
            if retries >= 3:
                return arg1 + kwarg
            else:
                try:
                    raise MyCustomException('Elaine Marie Benes')
                except MyCustomException as exc:
                    kwargs.update(kwarg=kwarg)
                    raise self.retry(countdown=0, exc=exc)

        self.retry_task_customexc = retry_task_customexc

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_unpickleable_exc(self, foo, bar):
            self.iterations += 1
            raise self.retry(countdown=0, exc=UnpickleableException(foo, bar))

        self.retry_task_unpickleable_exc = retry_task_unpickleable_exc

        @self.app.task(bind=True, autoretry_for=(ZeroDivisionError,),
                       shared=False)
        def autoretry_task_no_kwargs(self, a, b):
            self.iterations += 1
            return a / b

        self.autoretry_task_no_kwargs = autoretry_task_no_kwargs

        @self.app.task(bind=True, autoretry_for=(ZeroDivisionError,),
                       retry_kwargs={'max_retries': 5}, shared=False)
        def autoretry_task(self, a, b):
            self.iterations += 1
            return a / b

        self.autoretry_task = autoretry_task

        @self.app.task(bind=True, autoretry_for=(ArithmeticError,),
                       dont_autoretry_for=(ZeroDivisionError,),
                       retry_kwargs={'max_retries': 5}, shared=False)
        def autoretry_arith_task(self, a, b):
            self.iterations += 1
            return a / b

        self.autoretry_arith_task = autoretry_arith_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def autoretry_for_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.autoretry_for_from_base_task = autoretry_for_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       autoretry_for=(ZeroDivisionError,), shared=False)
        def override_autoretry_for_from_base_task(self, a, b):
            self.iterations += 1
            return a / b

        self.override_autoretry_for = override_autoretry_for_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def retry_kwargs_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.retry_kwargs_from_base_task = retry_kwargs_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       retry_kwargs={'max_retries': 2}, shared=False)
        def override_retry_kwargs_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.override_retry_kwargs = override_retry_kwargs_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def retry_backoff_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.retry_backoff_from_base_task = retry_backoff_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       retry_backoff=False, shared=False)
        def override_retry_backoff_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.override_retry_backoff = override_retry_backoff_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def retry_backoff_max_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.retry_backoff_max_from_base_task = retry_backoff_max_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       retry_backoff_max=16, shared=False)
        def override_retry_backoff_max_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.override_backoff_max = override_retry_backoff_max_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def retry_backoff_jitter_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.retry_backoff_jitter_from_base = retry_backoff_jitter_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       retry_jitter=True, shared=False)
        def override_backoff_jitter_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.override_backoff_jitter = override_backoff_jitter_from_base_task

        @self.app.task(bind=True)
        def task_check_request_context(self):
            assert self.request.hostname == socket.gethostname()

        self.task_check_request_context = task_check_request_context

        @self.app.task(ignore_result=True)
        def task_with_ignored_result():
            pass

        self.task_with_ignored_result = task_with_ignored_result

        @self.app.task(bind=True)
        def task_called_by_other_task(self):
            pass

        @self.app.task(bind=True)
        def task_which_calls_other_task(self):
            # Couldn't find a better way to mimic an apply_async()
            # request with set priority
            self.request.delivery_info['priority'] = 5

            task_called_by_other_task.delay()

        self.task_which_calls_other_task = task_which_calls_other_task

        @self.app.task(bind=True)
        def task_replacing_another_task(self):
            return "replaced"

        self.task_replacing_another_task = task_replacing_another_task

        @self.app.task(bind=True)
        def task_replaced_by_other_task(self):
            return self.replace(task_replacing_another_task.si())

        @self.app.task(bind=True, autoretry_for=(Exception,))
        def task_replaced_by_other_task_with_autoretry(self):
            return self.replace(task_replacing_another_task.si())

        self.task_replaced_by_other_task = task_replaced_by_other_task
        self.task_replaced_by_other_task_with_autoretry = task_replaced_by_other_task_with_autoretry

        # Remove all messages from memory-transport
        from kombu.transport.memory import Channel
        Channel.queues.clear()


class MyCustomException(Exception):
    """Random custom exception."""


class UnpickleableException(Exception):
    """Exception that doesn't survive a pickling roundtrip (dump + load)."""
    def __init__(self, foo, bar):
        super().__init__(foo)
        self.bar = bar


class test_task_retries(TasksCase):

    def test_retry(self):
        self.retry_task.max_retries = 3
        self.retry_task.iterations = 0
        self.retry_task.apply([0xFF, 0xFFFF])
        assert self.retry_task.iterations == 4

        self.retry_task.max_retries = 3
        self.retry_task.iterations = 0
        self.retry_task.apply([0xFF, 0xFFFF], {'max_retries': 10})
        assert self.retry_task.iterations == 11

    def test_retry_priority(self):
        priority = 7

        # Technically, task.priority doesn't need to be set here
        # since push_request() doesn't populate the delivery_info
        # with it. However, setting task.priority here also doesn't
        # cause any problems.
        self.retry_task.priority = priority

        self.retry_task.push_request()
        self.retry_task.request.delivery_info = {
            'priority': priority
        }
        sig = self.retry_task.signature_from_request()
        assert sig.options['priority'] == priority

    def test_retry_no_args(self):
        self.retry_task_noargs.max_retries = 3
        self.retry_task_noargs.iterations = 0
        self.retry_task_noargs.apply(propagate=True).get()
        assert self.retry_task_noargs.iterations == 4

    def test_signature_from_request__passes_headers(self):
        self.retry_task.push_request()
        self.retry_task.request.headers = {'custom': 10.1}
        sig = self.retry_task.signature_from_request()
        assert sig.options['headers']['custom'] == 10.1

    def test_signature_from_request__delivery_info(self):
        self.retry_task.push_request()
        self.retry_task.request.delivery_info = {
            'exchange': 'testex',
            'routing_key': 'testrk',
        }
        sig = self.retry_task.signature_from_request()
        assert sig.options['exchange'] == 'testex'
        assert sig.options['routing_key'] == 'testrk'

    def test_signature_from_request__shadow_name(self):
        self.retry_task.push_request()
        self.retry_task.request.shadow = 'test'
        sig = self.retry_task.signature_from_request()
        assert sig.options['shadow'] == 'test'

    def test_retry_kwargs_can_be_empty(self):
        self.retry_task_mockapply.push_request()
        try:
            with pytest.raises(Retry):
                import sys
                try:
                    sys.exc_clear()
                except AttributeError:
                    pass
                self.retry_task_mockapply.retry(args=[4, 4], kwargs=None)
        finally:
            self.retry_task_mockapply.pop_request()

    def test_retry_without_throw_eager(self):
        assert self.retry_task_return_without_throw.apply().get() == 42

    def test_raise_without_throw_eager(self):
        assert self.retry_task_raise_without_throw.apply().get() == 42

    def test_return_with_throw_eager(self):
        assert self.retry_task_return_with_throw.apply().get() == 42

    def test_eager_retry_with_single_new_params(self):
        assert self.retry_task_auto_retry_with_single_new_arg.apply().get() == "test"

    def test_eager_retry_with_new_params(self):
        assert self.retry_task_auto_retry_with_new_args.si(place_holder="test").apply().get() == "test"

    def test_eager_retry_with_autoretry_for_exception(self):
        assert self.retry_task_auto_retry_exception_with_new_args.si(place_holder="test").apply().get() == "test"

    def test_retry_task_max_retries_override(self):
        self.retry_task_max_retries_override.max_retries = 10
        self.retry_task_max_retries_override.iterations = 0
        result = self.retry_task_max_retries_override.apply()
        with pytest.raises(MyCustomException):
            result.get()
        assert self.retry_task_max_retries_override.iterations == 3

    def test_retry_task_explicit_exception(self):
        self.retry_task_explicit_exception.max_retries = 0
        self.retry_task_explicit_exception.iterations = 0
        result = self.retry_task_explicit_exception.apply()
        with pytest.raises(MyCustomException):
            result.get()
        assert self.retry_task_explicit_exception.iterations == 1

    def test_retry_eager_should_return_value(self):
        self.retry_task.max_retries = 3
        self.retry_task.iterations = 0
        assert self.retry_task.apply([0xFF, 0xFFFF]).get() == 0xFF
        assert self.retry_task.iterations == 4

    def test_retry_not_eager(self):
        self.retry_task_mockapply.push_request()
        try:
            self.retry_task_mockapply.request.called_directly = False
            exc = Exception('baz')
            try:
                self.retry_task_mockapply.retry(
                    args=[4, 4], kwargs={'task_retries': 0},
                    exc=exc, throw=False,
                )
                assert self.retry_task_mockapply.applied
            finally:
                self.retry_task_mockapply.applied = 0

            try:
                with pytest.raises(Retry):
                    self.retry_task_mockapply.retry(
                        args=[4, 4], kwargs={'task_retries': 0},
                        exc=exc, throw=True)
                assert self.retry_task_mockapply.applied
            finally:
                self.retry_task_mockapply.applied = 0
        finally:
            self.retry_task_mockapply.pop_request()

    def test_retry_with_kwargs(self):
        self.retry_task_customexc.max_retries = 3
        self.retry_task_customexc.iterations = 0
        self.retry_task_customexc.apply([0xFF, 0xFFFF], {'kwarg': 0xF})
        assert self.retry_task_customexc.iterations == 4

    def test_retry_with_custom_exception(self):
        self.retry_task_customexc.max_retries = 2
        self.retry_task_customexc.iterations = 0
        result = self.retry_task_customexc.apply(
            [0xFF, 0xFFFF], {'kwarg': 0xF},
        )
        with pytest.raises(MyCustomException):
            result.get()
        assert self.retry_task_customexc.iterations == 3

    def test_retry_with_unpickleable_exception(self):
        self.retry_task_unpickleable_exc.max_retries = 2
        self.retry_task_unpickleable_exc.iterations = 0

        result = self.retry_task_unpickleable_exc.apply(
            ["foo", "bar"]
        )
        with pytest.raises(UnpickleableExceptionWrapper) as exc_info:
            result.get()

        assert self.retry_task_unpickleable_exc.iterations == 3

        exc_wrapper = exc_info.value
        assert exc_wrapper.exc_cls_name == "UnpickleableException"
        assert exc_wrapper.exc_args == ("foo", )

    def test_max_retries_exceeded(self):
        self.retry_task.max_retries = 2
        self.retry_task.iterations = 0
        result = self.retry_task.apply([0xFF, 0xFFFF], {'care': False})
        with pytest.raises(self.retry_task.MaxRetriesExceededError):
            result.get()
        assert self.retry_task.iterations == 3

        self.retry_task.max_retries = 1
        self.retry_task.iterations = 0
        result = self.retry_task.apply([0xFF, 0xFFFF], {'care': False})
        with pytest.raises(self.retry_task.MaxRetriesExceededError):
            result.get()
        assert self.retry_task.iterations == 2

    def test_max_retries_exceeded_task_args(self):
        self.retry_task.max_retries = 2
        self.retry_task.iterations = 0
        args = (0xFF, 0xFFFF)
        kwargs = {'care': False}
        result = self.retry_task.apply(args, kwargs)
        with pytest.raises(self.retry_task.MaxRetriesExceededError) as e:
            result.get()

        assert e.value.task_args == args
        assert e.value.task_kwargs == kwargs

    def test_autoretry_no_kwargs(self):
        self.autoretry_task_no_kwargs.max_retries = 3
        self.autoretry_task_no_kwargs.iterations = 0
        self.autoretry_task_no_kwargs.apply((1, 0))
        assert self.autoretry_task_no_kwargs.iterations == 4

    def test_autoretry(self):
        self.autoretry_task.max_retries = 3
        self.autoretry_task.iterations = 0
        self.autoretry_task.apply((1, 0))
        assert self.autoretry_task.iterations == 6

    def test_autoretry_arith(self):
        self.autoretry_arith_task.max_retries = 3
        self.autoretry_arith_task.iterations = 0
        self.autoretry_arith_task.apply((1, 0))
        assert self.autoretry_arith_task.iterations == 1

    @pytest.mark.parametrize(
        'retry_backoff, expected_countdowns',
        [
            (False, [None, None, None, None]),
            (0, [None, None, None, None]),
            (0.0, [None, None, None, None]),
            (True, [1, 2, 4, 8]),
            (-1, [1, 2, 4, 8]),
            (0.1, [1, 2, 4, 8]),
            (1, [1, 2, 4, 8]),
            (1.9, [1, 2, 4, 8]),
            (2, [2, 4, 8, 16]),
        ],
    )
    def test_autoretry_backoff(self, retry_backoff, expected_countdowns):
        @self.app.task(bind=True, shared=False, autoretry_for=(ZeroDivisionError,),
                       retry_backoff=retry_backoff, retry_jitter=False, max_retries=3)
        def task(self_, x, y):
            self_.iterations += 1
            return x / y

        task.iterations = 0

        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, 0))

        assert task.iterations == 4
        retry_call_countdowns = [
            call_[1].get('countdown') for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == expected_countdowns

    @pytest.mark.parametrize(
        'retry_backoff, expected_countdowns',
        [
            (False, [None, None, None, None]),
            (0, [None, None, None, None]),
            (0.0, [None, None, None, None]),
            (True, [0, 1, 3, 7]),
            (-1, [0, 1, 3, 7]),
            (0.1, [0, 1, 3, 7]),
            (1, [0, 1, 3, 7]),
            (1.9, [0, 1, 3, 7]),
            (2, [1, 3, 7, 15]),
        ],
    )
    @patch('random.randrange', side_effect=lambda i: i - 2)
    def test_autoretry_backoff_jitter(self, randrange, retry_backoff, expected_countdowns):
        @self.app.task(bind=True, shared=False, autoretry_for=(HTTPError,),
                       retry_backoff=retry_backoff, retry_jitter=True, max_retries=3)
        def task(self_, url):
            self_.iterations += 1
            if "error" in url:
                fp = tempfile.TemporaryFile()
                raise HTTPError(url, '500', 'Error', '', fp)

        task.iterations = 0

        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply(("http://httpbin.org/error",))

        assert task.iterations == 4
        retry_call_countdowns = [
            call_[1].get('countdown') for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == expected_countdowns

    def test_autoretry_for_from_base(self):
        self.autoretry_for_from_base_task.iterations = 0
        self.autoretry_for_from_base_task.apply((1, "a"))
        assert self.autoretry_for_from_base_task.iterations == 6

    def test_override_autoretry_for_from_base(self):
        self.override_autoretry_for.iterations = 0
        self.override_autoretry_for.apply((1, 0))
        assert self.override_autoretry_for.iterations == 6

    def test_retry_kwargs_from_base(self):
        self.retry_kwargs_from_base_task.iterations = 0
        self.retry_kwargs_from_base_task.apply((1, "a"))
        assert self.retry_kwargs_from_base_task.iterations == 6

    def test_override_retry_kwargs_from_base(self):
        self.override_retry_kwargs.iterations = 0
        self.override_retry_kwargs.apply((1, "a"))
        assert self.override_retry_kwargs.iterations == 3

    def test_retry_backoff_from_base(self):
        task = self.retry_backoff_from_base_task
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [1, 2, 4, 8, 16, 32]

    @patch('celery.app.autoretry.get_exponential_backoff_interval')
    def test_override_retry_backoff_from_base(self, backoff):
        self.override_retry_backoff.iterations = 0
        self.override_retry_backoff.apply((1, "a"))
        assert self.override_retry_backoff.iterations == 6
        assert backoff.call_count == 0

    def test_retry_backoff_max_from_base(self):
        task = self.retry_backoff_max_from_base_task
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [1, 2, 4, 8, 16, 32]

    def test_override_retry_backoff_max_from_base(self):
        task = self.override_backoff_max
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [1, 2, 4, 8, 16, 16]

    def test_retry_backoff_jitter_from_base(self):
        task = self.retry_backoff_jitter_from_base
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [1, 2, 4, 8, 16, 32]

    @patch('random.randrange', side_effect=lambda i: i - 2)
    def test_override_backoff_jitter_from_base(self, randrange):
        task = self.override_backoff_jitter
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [0, 1, 3, 7, 15, 31]

    def test_retry_wrong_eta_when_not_enable_utc(self):
        """Issue #3753"""
        self.app.conf.enable_utc = False
        self.app.conf.timezone = 'US/Eastern'
        self.autoretry_task.iterations = 0
        self.autoretry_task.default_retry_delay = 2

        self.autoretry_task.apply((1, 0))
        assert self.autoretry_task.iterations == 6

    @pytest.mark.parametrize(
        'backoff_value, expected_countdowns',
        [
            (False, [None, None, None]),
            (0, [None, None, None]),
            (0.0, [None, None, None]),
            (True, [1, 2, 4]),
            (-1, [1, 2, 4]),
            (0.1, [1, 2, 4]),
            (1, [1, 2, 4]),
            (1.9, [1, 2, 4]),
            (2, [2, 4, 8]),
        ],
    )
    def test_autoretry_class_based_task(self, backoff_value, expected_countdowns):
        class ClassBasedAutoRetryTask(Task):
            name = 'ClassBasedAutoRetryTask'
            autoretry_for = (ZeroDivisionError,)
            retry_kwargs = {'max_retries': 2}
            retry_backoff = backoff_value
            retry_backoff_max = 700
            retry_jitter = False
            iterations = 0
            _app = self.app

            def run(self, x, y):
                self.iterations += 1
                return x / y

        task = ClassBasedAutoRetryTask()
        self.app.tasks.register(task)
        task.iterations = 0

        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, 0))

        assert task.iterations == 3
        retry_call_countdowns = [
            call_[1].get('countdown') for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == expected_countdowns


class test_canvas_utils(TasksCase):

    def test_si(self):
        assert self.retry_task.si()
        assert self.retry_task.si().immutable

    def test_chunks(self):
        assert self.retry_task.chunks(range(100), 10)

    def test_map(self):
        assert self.retry_task.map(range(100))

    def test_starmap(self):
        assert self.retry_task.starmap(range(100))

    def test_on_success(self):
        self.retry_task.on_success(1, 1, (), {})


class test_tasks(TasksCase):

    def now(self):
        return self.app.now()

    def test_typing(self):
        @self.app.task()
        def add(x, y, kw=1):
            pass

        with pytest.raises(TypeError):
            add.delay(1)

        with pytest.raises(TypeError):
            add.delay(1, kw=2)

        with pytest.raises(TypeError):
            add.delay(1, 2, foobar=3)

        add.delay(2, 2)

    def test_shadow_name(self):
        def shadow_name(task, args, kwargs, options):
            return 'fooxyz'

        @self.app.task(shadow_name=shadow_name)
        def shadowed():
            pass

        old_send_task = self.app.send_task
        self.app.send_task = Mock()

        shadowed.delay()

        self.app.send_task.assert_called_once_with(ANY, ANY, ANY,
                                                   compression=ANY,
                                                   delivery_mode=ANY,
                                                   exchange=ANY,
                                                   expires=ANY,
                                                   immediate=ANY,
                                                   link=ANY,
                                                   link_error=ANY,
                                                   mandatory=ANY,
                                                   priority=ANY,
                                                   producer=ANY,
                                                   queue=ANY,
                                                   result_cls=ANY,
                                                   routing_key=ANY,
                                                   serializer=ANY,
                                                   soft_time_limit=ANY,
                                                   task_id=ANY,
                                                   task_type=ANY,
                                                   time_limit=ANY,
                                                   shadow='fooxyz',
                                                   ignore_result=False)

        self.app.send_task = old_send_task

    def test_inherit_parent_priority_child_task(self):
        self.app.conf.task_inherit_parent_priority = True

        self.app.producer_or_acquire = Mock()
        self.app.producer_or_acquire.attach_mock(
            ContextMock(serializer='json'), 'return_value')
        self.app.amqp.send_task_message = Mock(name="send_task_message")

        self.task_which_calls_other_task.apply(args=[])

        self.app.amqp.send_task_message.assert_called_with(
            ANY, 't.unit.tasks.test_tasks.task_called_by_other_task',
            ANY, priority=5, queue=ANY, serializer=ANY)

    def test_typing__disabled(self):
        @self.app.task(typing=False)
        def add(x, y, kw=1):
            pass
        add.delay(1)
        add.delay(1, kw=2)
        add.delay(1, 2, foobar=3)

    def test_typing__disabled_by_app(self):
        with self.Celery(set_as_current=False, strict_typing=False) as app:
            @app.task()
            def add(x, y, kw=1):
                pass
            assert not add.typing
            add.delay(1)
            add.delay(1, kw=2)
            add.delay(1, 2, foobar=3)

    @pytest.mark.usefixtures('depends_on_current_app')
    def test_unpickle_task(self):
        import pickle

        @self.app.task(shared=True)
        def xxx():
            pass

        assert pickle.loads(pickle.dumps(xxx)) is xxx.app.tasks[xxx.name]

    @patch('celery.app.task.current_app')
    @pytest.mark.usefixtures('depends_on_current_app')
    def test_bind__no_app(self, current_app):

        class XTask(Task):
            _app = None

        XTask._app = None
        XTask.__bound__ = False
        XTask.bind = Mock(name='bind')
        assert XTask.app is current_app
        XTask.bind.assert_called_with(current_app)

    def test_reprtask__no_fmt(self):
        assert _reprtask(self.mytask)

    def test_AsyncResult(self):
        task_id = uuid()
        result = self.retry_task.AsyncResult(task_id)
        assert result.backend == self.retry_task.backend
        assert result.id == task_id

    def assert_next_task_data_equal(self, consumer, presult, task_name,
                                    test_eta=False, test_expires=False,
                                    properties=None, headers=None, **kwargs):
        next_task = consumer.queues[0].get(accept=['pickle', 'json'])
        task_properties = next_task.properties
        task_headers = next_task.headers
        task_body = next_task.decode()
        task_args, task_kwargs, embed = task_body
        assert task_headers['id'] == presult.id
        assert task_headers['task'] == task_name
        if test_eta:
            assert isinstance(task_headers.get('eta'), str)
            to_datetime = datetime.fromisoformat(task_headers.get('eta'))
            assert isinstance(to_datetime, datetime)
        if test_expires:
            assert isinstance(task_headers.get('expires'), str)
            to_datetime = datetime.fromisoformat(task_headers.get('expires'))
            assert isinstance(to_datetime, datetime)
        properties = properties or {}
        for arg_name, arg_value in properties.items():
            assert task_properties.get(arg_name) == arg_value
        headers = headers or {}
        for arg_name, arg_value in headers.items():
            assert task_headers.get(arg_name) == arg_value
        for arg_name, arg_value in kwargs.items():
            assert task_kwargs.get(arg_name) == arg_value

    def test_incomplete_task_cls(self):

        class IncompleteTask(Task):
            app = self.app
            name = 'c.unittest.t.itask'

        with pytest.raises(NotImplementedError):
            IncompleteTask().run()

    def test_task_kwargs_must_be_dictionary(self):
        with pytest.raises(TypeError):
            self.increment_counter.apply_async([], 'str')

    def test_task_args_must_be_list(self):
        with pytest.raises(TypeError):
            self.increment_counter.apply_async('s', {})

    def test_regular_task(self):
        assert isinstance(self.mytask, Task)
        assert self.mytask.run()
        assert callable(self.mytask)
        assert self.mytask(), 'Task class runs run() when called'

        with self.app.connection_or_acquire() as conn:
            consumer = self.app.amqp.TaskConsumer(conn)
            with pytest.raises(NotImplementedError):
                consumer.receive('foo', 'foo')
            consumer.purge()
            assert consumer.queues[0].get() is None
            self.app.amqp.TaskConsumer(conn, queues=[Queue('foo')])

            # Without arguments.
            presult = self.mytask.delay()
            self.assert_next_task_data_equal(
                consumer, presult, self.mytask.name)

            # With arguments.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name, name='George Costanza',
            )

            # send_task
            sresult = self.app.send_task(self.mytask.name,
                                         kwargs={'name': 'Elaine M. Benes'})
            self.assert_next_task_data_equal(
                consumer, sresult, self.mytask.name, name='Elaine M. Benes',
            )

            # With ETA, absolute expires.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
                eta=self.now() + timedelta(days=1),
                expires=self.now() + timedelta(days=2),
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # With ETA, absolute expires without timezone.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Constanza'},
                eta=self.now() + timedelta(days=1),
                expires=(self.now() + timedelta(hours=2)).replace(tzinfo=None),
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Constanza', test_eta=True, test_expires=True,
            )

            # With ETA, absolute expires in the past.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
                eta=self.now() + timedelta(days=1),
                expires=self.now() - timedelta(days=2),
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # With ETA, relative expires.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
                eta=self.now() + timedelta(days=1),
                expires=2 * 24 * 60 * 60,
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # With countdown.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'}, countdown=10, expires=12,
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # With ETA, absolute expires in the past in ISO format.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
                eta=self.now() + timedelta(days=1),
                expires=self.now() - timedelta(days=2),
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # Default argsrepr/kwargsrepr behavior
            presult2 = self.mytask.apply_async(
                args=('spam',), kwargs={'name': 'Jerry Seinfeld'}
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                headers={'argsrepr': "('spam',)",
                         'kwargsrepr': "{'name': 'Jerry Seinfeld'}"},
            )

            # With argsrepr/kwargsrepr
            presult2 = self.mytask.apply_async(
                args=('secret',), argsrepr="'***'",
                kwargs={'password': 'foo'}, kwargsrepr="{'password': '***'}",
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                headers={'argsrepr': "'***'",
                         'kwargsrepr': "{'password': '***'}"},
            )

            # Discarding all tasks.
            consumer.purge()
            self.mytask.apply_async()
            assert consumer.purge() == 1
            assert consumer.queues[0].get() is None

            assert not presult.successful()
            self.mytask.backend.mark_as_done(presult.id, result=None)
            assert presult.successful()

    def test_send_event(self):
        mytask = self.mytask._get_current_object()
        mytask.app.events = Mock(name='events')
        mytask.app.events.attach_mock(ContextMock(), 'default_dispatcher')
        mytask.request.id = 'fb'
        mytask.send_event('task-foo', id=3122)
        mytask.app.events.default_dispatcher().send.assert_called_with(
            'task-foo', uuid='fb', id=3122,
            retry=True, retry_policy=self.app.conf.task_publish_retry_policy)

    @pytest.mark.usefixtures('depends_on_current_app')
    def test_on_replace(self):
        class CustomStampingVisitor(StampingVisitor):
            def on_signature(self, sig, **headers) -> dict:
                return {'header': 'value'}

        class MyTask(Task):
            def on_replace(self, sig):
                sig.stamp(CustomStampingVisitor())
                return super().on_replace(sig)

        mytask = self.app.task(shared=False, base=MyTask)(return_True)

        sig1 = signature('sig1')
        with pytest.raises(Ignore):
            mytask.replace(sig1)
        assert sig1.options['header'] == 'value'

    def test_replace(self):
        sig1 = MagicMock(name='sig1')
        sig1.options = {}
        self.mytask.request.id = sentinel.request_id
        with pytest.raises(Ignore):
            self.mytask.replace(sig1)
        sig1.freeze.assert_called_once_with(self.mytask.request.id)
        sig1.set.assert_called_once_with(replaced_task_nesting=1,
                                         chord=ANY,
                                         group_id=ANY,
                                         group_index=ANY,
                                         root_id=ANY)

    def test_replace_with_chord(self):
        sig1 = Mock(name='sig1')
        sig1.options = {'chord': None}
        with pytest.raises(ImproperlyConfigured):
            self.mytask.replace(sig1)

    def test_replace_callback(self):
        c = group([self.mytask.s()], app=self.app)
        c.freeze = Mock(name='freeze')
        c.delay = Mock(name='delay')
        self.mytask.request.id = 'id'
        self.mytask.request.group = 'group'
        self.mytask.request.root_id = 'root_id'
        self.mytask.request.callbacks = callbacks = 'callbacks'
        self.mytask.request.errbacks = errbacks = 'errbacks'

        # Replacement groups get uplifted to chords so that we can accumulate
        # the results and link call/errbacks - patch the appropriate `chord`
        # methods so we can validate this behaviour
        with patch(
            "celery.canvas.chord.link"
        ) as mock_chord_link, patch(
            "celery.canvas.chord.link_error"
        ) as mock_chord_link_error:
            with pytest.raises(Ignore):
                self.mytask.replace(c)
        # Confirm that the call/errbacks on the original signature are linked
        # to the replacement signature as expected
        mock_chord_link.assert_called_once_with(callbacks)
        mock_chord_link_error.assert_called_once_with(errbacks)

    def test_replace_group(self):
        c = group([self.mytask.s()], app=self.app)
        c.freeze = Mock(name='freeze')
        c.delay = Mock(name='delay')
        self.mytask.request.id = 'id'
        self.mytask.request.group = 'group'
        self.mytask.request.root_id = 'root_id',
        with pytest.raises(Ignore):
            self.mytask.replace(c)

    def test_replace_run(self):
        with pytest.raises(Ignore):
            self.task_replaced_by_other_task.run()

    def test_replace_run_with_autoretry(self):
        with pytest.raises(Ignore):
            self.task_replaced_by_other_task_with_autoretry.run()

    def test_replace_delay(self):
        res = self.task_replaced_by_other_task.delay()
        assert isinstance(res, AsyncResult)

    def test_replace_apply(self):
        res = self.task_replaced_by_other_task.apply()
        assert isinstance(res, EagerResult)
        assert res.get() == "replaced"

    def test_add_trail__no_trail(self):
        mytask = self.increment_counter._get_current_object()
        mytask.trail = False
        mytask.add_trail('foo')

    def test_repr_v2_compat(self):
        self.mytask.__v2_compat__ = True
        assert 'v2 compatible' in repr(self.mytask)

    def test_context_get(self):
        self.mytask.push_request()
        try:
            request = self.mytask.request
            request.foo = 32
            assert request.get('foo') == 32
            assert request.get('bar', 36) == 36
            request.clear()
        finally:
            self.mytask.pop_request()

    def test_annotate(self):
        with patch('celery.app.task.resolve_all_annotations') as anno:
            anno.return_value = [{'FOO': 'BAR'}]

            @self.app.task(shared=False)
            def task():
                pass

            task.annotate()
            assert task.FOO == 'BAR'

    def test_after_return(self):
        self.mytask.push_request()
        try:
            self.mytask.request.chord = self.mytask.s()
            self.mytask.after_return('SUCCESS', 1.0, 'foobar', (), {}, None)
            self.mytask.request.clear()
        finally:
            self.mytask.pop_request()

    def test_update_state(self):

        @self.app.task(shared=False)
        def yyy():
            pass

        yyy.push_request()
        try:
            tid = uuid()
            # update_state should accept arbitrary kwargs, which are passed to
            # the backend store_result method
            yyy.update_state(tid, 'FROBULATING', {'fooz': 'baaz'},
                             arbitrary_kwarg=None)
            assert yyy.AsyncResult(tid).status == 'FROBULATING'
            assert yyy.AsyncResult(tid).result == {'fooz': 'baaz'}

            yyy.request.id = tid
            yyy.update_state(state='FROBUZATING', meta={'fooz': 'baaz'})
            assert yyy.AsyncResult(tid).status == 'FROBUZATING'
            assert yyy.AsyncResult(tid).result == {'fooz': 'baaz'}
        finally:
            yyy.pop_request()

    def test_update_state_passes_request_to_backend(self):
        backend = Mock()

        @self.app.task(shared=False, backend=backend)
        def ttt():
            pass

        ttt.push_request()

        tid = uuid()
        ttt.update_state(tid, 'SHRIMMING', {'foo': 'bar'})

        backend.store_result.assert_called_once_with(
            tid, {'foo': 'bar'}, 'SHRIMMING', request=ttt.request
        )

    def test_repr(self):

        @self.app.task(shared=False)
        def task_test_repr():
            pass

        assert 'task_test_repr' in repr(task_test_repr)

    def test_has___name__(self):

        @self.app.task(shared=False)
        def yyy2():
            pass

        assert yyy2.__name__

    def test_default_priority(self):

        @self.app.task(shared=False)
        def yyy3():
            pass

        @self.app.task(shared=False, priority=66)
        def yyy4():
            pass

        @self.app.task(shared=False, bind=True, base=TaskWithPriority)
        def yyy5(self):
            pass

        self.app.conf.task_default_priority = 42
        old_send_task = self.app.send_task

        self.app.send_task = Mock()
        yyy3.delay()
        self.app.send_task.assert_called_once_with(ANY, ANY, ANY,
                                                   compression=ANY,
                                                   delivery_mode=ANY,
                                                   exchange=ANY,
                                                   expires=ANY,
                                                   immediate=ANY,
                                                   link=ANY,
                                                   link_error=ANY,
                                                   mandatory=ANY,
                                                   priority=42,
                                                   producer=ANY,
                                                   queue=ANY,
                                                   result_cls=ANY,
                                                   routing_key=ANY,
                                                   serializer=ANY,
                                                   soft_time_limit=ANY,
                                                   task_id=ANY,
                                                   task_type=ANY,
                                                   time_limit=ANY,
                                                   shadow=None,
                                                   ignore_result=False)

        self.app.send_task = Mock()
        yyy4.delay()
        self.app.send_task.assert_called_once_with(ANY, ANY, ANY,
                                                   compression=ANY,
                                                   delivery_mode=ANY,
                                                   exchange=ANY,
                                                   expires=ANY,
                                                   immediate=ANY,
                                                   link=ANY,
                                                   link_error=ANY,
                                                   mandatory=ANY,
                                                   priority=66,
                                                   producer=ANY,
                                                   queue=ANY,
                                                   result_cls=ANY,
                                                   routing_key=ANY,
                                                   serializer=ANY,
                                                   soft_time_limit=ANY,
                                                   task_id=ANY,
                                                   task_type=ANY,
                                                   time_limit=ANY,
                                                   shadow=None,
                                                   ignore_result=False)

        self.app.send_task = Mock()
        yyy5.delay()
        self.app.send_task.assert_called_once_with(ANY, ANY, ANY,
                                                   compression=ANY,
                                                   delivery_mode=ANY,
                                                   exchange=ANY,
                                                   expires=ANY,
                                                   immediate=ANY,
                                                   link=ANY,
                                                   link_error=ANY,
                                                   mandatory=ANY,
                                                   priority=10,
                                                   producer=ANY,
                                                   queue=ANY,
                                                   result_cls=ANY,
                                                   routing_key=ANY,
                                                   serializer=ANY,
                                                   soft_time_limit=ANY,
                                                   task_id=ANY,
                                                   task_type=ANY,
                                                   time_limit=ANY,
                                                   shadow=None,
                                                   ignore_result=False)

        self.app.send_task = old_send_task


class test_apply_task(TasksCase):

    def test_apply_throw(self):
        with pytest.raises(KeyError):
            self.raising.apply(throw=True)

    def test_apply_with_task_eager_propagates(self):
        self.app.conf.task_eager_propagates = True
        with pytest.raises(KeyError):
            self.raising.apply()

    def test_apply_request_context_is_ok(self):
        self.app.conf.task_eager_propagates = True
        self.task_check_request_context.apply()

    def test_apply(self):
        self.increment_counter.count = 0

        e = self.increment_counter.apply()
        assert isinstance(e, EagerResult)
        assert e.get() == 1

        e = self.increment_counter.apply(args=[1])
        assert e.get() == 2

        e = self.increment_counter.apply(kwargs={'increment_by': 4})
        assert e.get() == 6

        assert e.successful()
        assert e.ready()
        assert repr(e).startswith('<EagerResult:')

        f = self.raising.apply()
        assert f.ready()
        assert not f.successful()
        assert f.traceback
        with pytest.raises(KeyError):
            f.get()

    def test_apply_simulates_delivery_info(self):
        task_to_apply = self.task_check_request_context
        with patch.object(
            task_to_apply.request_stack, "push",
            wraps=task_to_apply.request_stack.push,
        ) as mock_push:
            task_to_apply.apply(
                priority=4,
                routing_key='myroutingkey',
                exchange='myexchange',
            )

        mock_push.assert_called_once()

        request = mock_push.call_args[0][0]

        assert request.delivery_info == {
            'is_eager': True,
            'exchange': 'myexchange',
            'routing_key': 'myroutingkey',
            'priority': 4,
        }


class test_apply_async(TasksCase):
    def common_send_task_arguments(self):
        return (ANY, ANY, ANY), dict(
            compression=ANY,
            delivery_mode=ANY,
            exchange=ANY,
            expires=ANY,
            immediate=ANY,
            link=ANY,
            link_error=ANY,
            mandatory=ANY,
            priority=ANY,
            producer=ANY,
            queue=ANY,
            result_cls=ANY,
            routing_key=ANY,
            serializer=ANY,
            soft_time_limit=ANY,
            task_id=ANY,
            task_type=ANY,
            time_limit=ANY,
            shadow=None,
            ignore_result=False
        )

    def test_eager_serialization_failure(self):
        @self.app.task
        def task(*args, **kwargs):
            pass
        with pytest.raises(EncodeError):
            task.apply_async((1, 2, 3, 4, {1}))

    def test_eager_serialization_uses_task_serializer_setting(self):
        @self.app.task
        def task(*args, **kwargs):
            pass
        with pytest.raises(EncodeError):
            task.apply_async((1, 2, 3, 4, {1}))

        self.app.conf.task_serializer = 'pickle'

        @self.app.task
        def task2(*args, **kwargs):
            pass
        task2.apply_async((1, 2, 3, 4, {1}))

    def test_always_eager_with_task_serializer_option(self):
        self.app.conf.task_always_eager = True
        self.app.conf.task_serializer = 'pickle'

        @self.app.task
        def task(*args, **kwargs):
            pass
        task.apply_async((1, 2, 3, 4, {1}))

    def test_always_eager_uses_task_serializer_setting(self):
        self.app.conf.task_always_eager = True

        @self.app.task(serializer='pickle')
        def task(*args, **kwargs):
            pass
        task.apply_async((1, 2, 3, 4, {1}))

    def test_task_with_ignored_result(self):
        with patch.object(self.app, 'send_task') as send_task:
            self.task_with_ignored_result.apply_async()
            expected_args, expected_kwargs = self.common_send_task_arguments()
            expected_kwargs['ignore_result'] = True
            send_task.assert_called_once_with(
                *expected_args,
                **expected_kwargs
            )

    def test_task_with_result(self):
        with patch.object(self.app, 'send_task') as send_task:
            self.mytask.apply_async()
            expected_args, expected_kwargs = self.common_send_task_arguments()
            send_task.assert_called_once_with(
                *expected_args,
                **expected_kwargs
            )

    def test_task_with_result_ignoring_on_call(self):
        with patch.object(self.app, 'send_task') as send_task:
            self.mytask.apply_async(ignore_result=True)
            expected_args, expected_kwargs = self.common_send_task_arguments()
            expected_kwargs['ignore_result'] = True
            send_task.assert_called_once_with(
                *expected_args,
                **expected_kwargs
            )

import socket
import tempfile
from datetime import datetime, timedelta
from unittest.mock import ANY, MagicMock, Mock, patch, sentinel

import pytest
from kombu import Queue
from kombu.exceptions import EncodeError

from celery import Task, chain, group, uuid
from celery.app.task import _reprtask
from celery.canvas import StampingVisitor, signature
from celery.contrib.testing.mocks import ContextMock
from celery.exceptions import Ignore, ImproperlyConfigured, Retry
from celery.result import AsyncResult, EagerResult
from celery.utils.serialization import UnpickleableExceptionWrapper

try:
    from urllib.error import HTTPError
except ImportError:
    from urllib2 import HTTPError


def return_True(*args, **kwargs):
    # Task run functions can't be closures/lambdas, as they're pickled.
    return True


class MockApplyTask(Task):
    abstract = True
    applied = 0

    def run(self, x, y):
        return x * y

    def apply_async(self, *args, **kwargs):
        self.applied += 1


class TaskWithPriority(Task):
    priority = 10


class TaskWithRetry(Task):
    autoretry_for = (TypeError,)
    retry_kwargs = {'max_retries': 5}
    retry_backoff = True
    retry_backoff_max = 700
    retry_jitter = False


class TaskWithRetryButForTypeError(Task):
    autoretry_for = (Exception,)
    dont_autoretry_for = (TypeError,)
    retry_kwargs = {'max_retries': 5}
    retry_backoff = True
    retry_backoff_max = 700
    retry_jitter = False


class TasksCase:

    def setup_method(self):
        self.mytask = self.app.task(shared=False)(return_True)

        @self.app.task(bind=True, count=0, shared=False)
        def increment_counter(self, increment_by=1):
            self.count += increment_by or 1
            return self.count

        self.increment_counter = increment_counter

        @self.app.task(shared=False)
        def raising():
            raise KeyError('foo')

        self.raising = raising

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task(self, arg1, arg2, kwarg=1, max_retries=None, care=True):
            self.iterations += 1
            rmax = self.max_retries if max_retries is None else max_retries

            assert repr(self.request)
            retries = self.request.retries
            if care and retries >= rmax:
                return arg1
            else:
                raise self.retry(countdown=0, max_retries=rmax)

        self.retry_task = retry_task

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_noargs(self, **kwargs):
            self.iterations += 1

            if self.request.retries >= 3:
                return 42
            else:
                raise self.retry(countdown=0)

        self.retry_task_noargs = retry_task_noargs

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_return_without_throw(self, **kwargs):
            self.iterations += 1
            try:
                if self.request.retries >= 3:
                    return 42
                else:
                    raise Exception("random code exception")
            except Exception as exc:
                return self.retry(exc=exc, throw=False)

        self.retry_task_return_without_throw = retry_task_return_without_throw

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_return_with_throw(self, **kwargs):
            self.iterations += 1
            try:
                if self.request.retries >= 3:
                    return 42
                else:
                    raise Exception("random code exception")
            except Exception as exc:
                return self.retry(exc=exc, throw=True)

        self.retry_task_return_with_throw = retry_task_return_with_throw

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False, autoretry_for=(Exception,))
        def retry_task_auto_retry_with_single_new_arg(self, ret=None, **kwargs):
            if ret is None:
                return self.retry(exc=Exception("I have filled now"), args=["test"], kwargs=kwargs)
            else:
                return ret

        self.retry_task_auto_retry_with_single_new_arg = retry_task_auto_retry_with_single_new_arg

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_auto_retry_with_new_args(self, ret=None, place_holder=None, **kwargs):
            if ret is None:
                return self.retry(args=[place_holder, place_holder], kwargs=kwargs)
            else:
                return ret

        self.retry_task_auto_retry_with_new_args = retry_task_auto_retry_with_new_args

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False, autoretry_for=(Exception,))
        def retry_task_auto_retry_exception_with_new_args(self, ret=None, place_holder=None, **kwargs):
            if ret is None:
                return self.retry(exc=Exception("I have filled"), args=[place_holder, place_holder], kwargs=kwargs)
            else:
                return ret

        self.retry_task_auto_retry_exception_with_new_args = retry_task_auto_retry_exception_with_new_args

        @self.app.task(bind=True, max_retries=10, iterations=0, shared=False,
                       autoretry_for=(Exception,))
        def retry_task_max_retries_override(self, **kwargs):
            # Test for #6436
            self.iterations += 1
            if self.iterations == 3:
                # I wanna force fail here cause i have enough
                self.retry(exc=MyCustomException, max_retries=0)
            self.retry(exc=MyCustomException)

        self.retry_task_max_retries_override = retry_task_max_retries_override

        @self.app.task(bind=True, max_retries=0, iterations=0, shared=False,
                       autoretry_for=(Exception,))
        def retry_task_explicit_exception(self, **kwargs):
            # Test for #6436
            self.iterations += 1
            raise MyCustomException()

        self.retry_task_explicit_exception = retry_task_explicit_exception

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_raise_without_throw(self, **kwargs):
            self.iterations += 1
            try:
                if self.request.retries >= 3:
                    return 42
                else:
                    raise Exception("random code exception")
            except Exception as exc:
                raise self.retry(exc=exc, throw=False)

        self.retry_task_raise_without_throw = retry_task_raise_without_throw

        @self.app.task(bind=True, max_retries=3, iterations=0,
                       base=MockApplyTask, shared=False)
        def retry_task_mockapply(self, arg1, arg2, kwarg=1):
            self.iterations += 1

            retries = self.request.retries
            if retries >= 3:
                return arg1
            raise self.retry(countdown=0)

        self.retry_task_mockapply = retry_task_mockapply

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_customexc(self, arg1, arg2, kwarg=1, **kwargs):
            self.iterations += 1

            retries = self.request.retries
            if retries >= 3:
                return arg1 + kwarg
            else:
                try:
                    raise MyCustomException('Elaine Marie Benes')
                except MyCustomException as exc:
                    kwargs.update(kwarg=kwarg)
                    raise self.retry(countdown=0, exc=exc)

        self.retry_task_customexc = retry_task_customexc

        @self.app.task(bind=True, max_retries=3, iterations=0, shared=False)
        def retry_task_unpickleable_exc(self, foo, bar):
            self.iterations += 1
            raise self.retry(countdown=0, exc=UnpickleableException(foo, bar))

        self.retry_task_unpickleable_exc = retry_task_unpickleable_exc

        @self.app.task(bind=True, autoretry_for=(ZeroDivisionError,),
                       shared=False)
        def autoretry_task_no_kwargs(self, a, b):
            self.iterations += 1
            return a / b

        self.autoretry_task_no_kwargs = autoretry_task_no_kwargs

        @self.app.task(bind=True, autoretry_for=(ZeroDivisionError,),
                       retry_kwargs={'max_retries': 5}, shared=False)
        def autoretry_task(self, a, b):
            self.iterations += 1
            return a / b

        self.autoretry_task = autoretry_task

        @self.app.task(bind=True, autoretry_for=(ArithmeticError,),
                       dont_autoretry_for=(ZeroDivisionError,),
                       retry_kwargs={'max_retries': 5}, shared=False)
        def autoretry_arith_task(self, a, b):
            self.iterations += 1
            return a / b

        self.autoretry_arith_task = autoretry_arith_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def autoretry_for_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.autoretry_for_from_base_task = autoretry_for_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       autoretry_for=(ZeroDivisionError,), shared=False)
        def override_autoretry_for_from_base_task(self, a, b):
            self.iterations += 1
            return a / b

        self.override_autoretry_for = override_autoretry_for_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def retry_kwargs_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.retry_kwargs_from_base_task = retry_kwargs_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       retry_kwargs={'max_retries': 2}, shared=False)
        def override_retry_kwargs_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.override_retry_kwargs = override_retry_kwargs_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def retry_backoff_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.retry_backoff_from_base_task = retry_backoff_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       retry_backoff=False, shared=False)
        def override_retry_backoff_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.override_retry_backoff = override_retry_backoff_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def retry_backoff_max_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.retry_backoff_max_from_base_task = retry_backoff_max_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       retry_backoff_max=16, shared=False)
        def override_retry_backoff_max_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.override_backoff_max = override_retry_backoff_max_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry, shared=False)
        def retry_backoff_jitter_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.retry_backoff_jitter_from_base = retry_backoff_jitter_from_base_task

        @self.app.task(bind=True, base=TaskWithRetry,
                       retry_jitter=True, shared=False)
        def override_backoff_jitter_from_base_task(self, a, b):
            self.iterations += 1
            return a + b

        self.override_backoff_jitter = override_backoff_jitter_from_base_task

        @self.app.task(bind=True)
        def task_check_request_context(self):
            assert self.request.hostname == socket.gethostname()

        self.task_check_request_context = task_check_request_context

        @self.app.task(ignore_result=True)
        def task_with_ignored_result():
            pass

        self.task_with_ignored_result = task_with_ignored_result

        @self.app.task(bind=True)
        def task_called_by_other_task(self):
            pass

        @self.app.task(bind=True)
        def task_which_calls_other_task(self):
            # Couldn't find a better way to mimic an apply_async()
            # request with set priority
            self.request.delivery_info['priority'] = 5

            task_called_by_other_task.delay()

        self.task_which_calls_other_task = task_which_calls_other_task

        @self.app.task(bind=True)
        def task_replacing_another_task(self):
            return "replaced"

        self.task_replacing_another_task = task_replacing_another_task

        @self.app.task(bind=True)
        def task_replaced_by_other_task(self):
            return self.replace(task_replacing_another_task.si())

        @self.app.task(bind=True, autoretry_for=(Exception,))
        def task_replaced_by_other_task_with_autoretry(self):
            return self.replace(task_replacing_another_task.si())

        self.task_replaced_by_other_task = task_replaced_by_other_task
        self.task_replaced_by_other_task_with_autoretry = task_replaced_by_other_task_with_autoretry

        # Remove all messages from memory-transport
        from kombu.transport.memory import Channel
        Channel.queues.clear()


class MyCustomException(Exception):
    """Random custom exception."""


class UnpickleableException(Exception):
    """Exception that doesn't survive a pickling roundtrip (dump + load)."""
    def __init__(self, foo, bar):
        super().__init__(foo)
        self.bar = bar


class test_task_retries(TasksCase):

    def test_retry(self):
        self.retry_task.max_retries = 3
        self.retry_task.iterations = 0
        self.retry_task.apply([0xFF, 0xFFFF])
        assert self.retry_task.iterations == 4

        self.retry_task.max_retries = 3
        self.retry_task.iterations = 0
        self.retry_task.apply([0xFF, 0xFFFF], {'max_retries': 10})
        assert self.retry_task.iterations == 11

    def test_retry_priority(self):
        priority = 7

        # Technically, task.priority doesn't need to be set here
        # since push_request() doesn't populate the delivery_info
        # with it. However, setting task.priority here also doesn't
        # cause any problems.
        self.retry_task.priority = priority

        self.retry_task.push_request()
        self.retry_task.request.delivery_info = {
            'priority': priority
        }
        sig = self.retry_task.signature_from_request()
        assert sig.options['priority'] == priority

    def test_retry_no_args(self):
        self.retry_task_noargs.max_retries = 3
        self.retry_task_noargs.iterations = 0
        self.retry_task_noargs.apply(propagate=True).get()
        assert self.retry_task_noargs.iterations == 4

    def test_signature_from_request__passes_headers(self):
        self.retry_task.push_request()
        self.retry_task.request.headers = {'custom': 10.1}
        sig = self.retry_task.signature_from_request()
        assert sig.options['headers']['custom'] == 10.1

    def test_signature_from_request__delivery_info(self):
        self.retry_task.push_request()
        self.retry_task.request.delivery_info = {
            'exchange': 'testex',
            'routing_key': 'testrk',
        }
        sig = self.retry_task.signature_from_request()
        assert sig.options['exchange'] == 'testex'
        assert sig.options['routing_key'] == 'testrk'

    def test_signature_from_request__shadow_name(self):
        self.retry_task.push_request()
        self.retry_task.request.shadow = 'test'
        sig = self.retry_task.signature_from_request()
        assert sig.options['shadow'] == 'test'

    def test_retry_kwargs_can_be_empty(self):
        self.retry_task_mockapply.push_request()
        try:
            with pytest.raises(Retry):
                import sys
                try:
                    sys.exc_clear()
                except AttributeError:
                    pass
                self.retry_task_mockapply.retry(args=[4, 4], kwargs=None)
        finally:
            self.retry_task_mockapply.pop_request()

    def test_retry_without_throw_eager(self):
        assert self.retry_task_return_without_throw.apply().get() == 42

    def test_raise_without_throw_eager(self):
        assert self.retry_task_raise_without_throw.apply().get() == 42

    def test_return_with_throw_eager(self):
        assert self.retry_task_return_with_throw.apply().get() == 42

    def test_eager_retry_with_single_new_params(self):
        assert self.retry_task_auto_retry_with_single_new_arg.apply().get() == "test"

    def test_eager_retry_with_new_params(self):
        assert self.retry_task_auto_retry_with_new_args.si(place_holder="test").apply().get() == "test"

    def test_eager_retry_with_autoretry_for_exception(self):
        assert self.retry_task_auto_retry_exception_with_new_args.si(place_holder="test").apply().get() == "test"

    def test_retry_task_max_retries_override(self):
        self.retry_task_max_retries_override.max_retries = 10
        self.retry_task_max_retries_override.iterations = 0
        result = self.retry_task_max_retries_override.apply()
        with pytest.raises(MyCustomException):
            result.get()
        assert self.retry_task_max_retries_override.iterations == 3

    def test_retry_task_explicit_exception(self):
        self.retry_task_explicit_exception.max_retries = 0
        self.retry_task_explicit_exception.iterations = 0
        result = self.retry_task_explicit_exception.apply()
        with pytest.raises(MyCustomException):
            result.get()
        assert self.retry_task_explicit_exception.iterations == 1

    def test_retry_eager_should_return_value(self):
        self.retry_task.max_retries = 3
        self.retry_task.iterations = 0
        assert self.retry_task.apply([0xFF, 0xFFFF]).get() == 0xFF
        assert self.retry_task.iterations == 4

    def test_retry_not_eager(self):
        self.retry_task_mockapply.push_request()
        try:
            self.retry_task_mockapply.request.called_directly = False
            exc = Exception('baz')
            try:
                self.retry_task_mockapply.retry(
                    args=[4, 4], kwargs={'task_retries': 0},
                    exc=exc, throw=False,
                )
                assert self.retry_task_mockapply.applied
            finally:
                self.retry_task_mockapply.applied = 0

            try:
                with pytest.raises(Retry):
                    self.retry_task_mockapply.retry(
                        args=[4, 4], kwargs={'task_retries': 0},
                        exc=exc, throw=True)
                assert self.retry_task_mockapply.applied
            finally:
                self.retry_task_mockapply.applied = 0
        finally:
            self.retry_task_mockapply.pop_request()

    def test_retry_with_kwargs(self):
        self.retry_task_customexc.max_retries = 3
        self.retry_task_customexc.iterations = 0
        self.retry_task_customexc.apply([0xFF, 0xFFFF], {'kwarg': 0xF})
        assert self.retry_task_customexc.iterations == 4

    def test_retry_with_custom_exception(self):
        self.retry_task_customexc.max_retries = 2
        self.retry_task_customexc.iterations = 0
        result = self.retry_task_customexc.apply(
            [0xFF, 0xFFFF], {'kwarg': 0xF},
        )
        with pytest.raises(MyCustomException):
            result.get()
        assert self.retry_task_customexc.iterations == 3

    def test_retry_with_unpickleable_exception(self):
        self.retry_task_unpickleable_exc.max_retries = 2
        self.retry_task_unpickleable_exc.iterations = 0

        result = self.retry_task_unpickleable_exc.apply(
            ["foo", "bar"]
        )
        with pytest.raises(UnpickleableExceptionWrapper) as exc_info:
            result.get()

        assert self.retry_task_unpickleable_exc.iterations == 3

        exc_wrapper = exc_info.value
        assert exc_wrapper.exc_cls_name == "UnpickleableException"
        assert exc_wrapper.exc_args == ("foo", )

    def test_max_retries_exceeded(self):
        self.retry_task.max_retries = 2
        self.retry_task.iterations = 0
        result = self.retry_task.apply([0xFF, 0xFFFF], {'care': False})
        with pytest.raises(self.retry_task.MaxRetriesExceededError):
            result.get()
        assert self.retry_task.iterations == 3

        self.retry_task.max_retries = 1
        self.retry_task.iterations = 0
        result = self.retry_task.apply([0xFF, 0xFFFF], {'care': False})
        with pytest.raises(self.retry_task.MaxRetriesExceededError):
            result.get()
        assert self.retry_task.iterations == 2

    def test_max_retries_exceeded_task_args(self):
        self.retry_task.max_retries = 2
        self.retry_task.iterations = 0
        args = (0xFF, 0xFFFF)
        kwargs = {'care': False}
        result = self.retry_task.apply(args, kwargs)
        with pytest.raises(self.retry_task.MaxRetriesExceededError) as e:
            result.get()

        assert e.value.task_args == args
        assert e.value.task_kwargs == kwargs

    def test_autoretry_no_kwargs(self):
        self.autoretry_task_no_kwargs.max_retries = 3
        self.autoretry_task_no_kwargs.iterations = 0
        self.autoretry_task_no_kwargs.apply((1, 0))
        assert self.autoretry_task_no_kwargs.iterations == 4

    def test_autoretry(self):
        self.autoretry_task.max_retries = 3
        self.autoretry_task.iterations = 0
        self.autoretry_task.apply((1, 0))
        assert self.autoretry_task.iterations == 6

    def test_autoretry_arith(self):
        self.autoretry_arith_task.max_retries = 3
        self.autoretry_arith_task.iterations = 0
        self.autoretry_arith_task.apply((1, 0))
        assert self.autoretry_arith_task.iterations == 1

    @pytest.mark.parametrize(
        'retry_backoff, expected_countdowns',
        [
            (False, [None, None, None, None]),
            (0, [None, None, None, None]),
            (0.0, [None, None, None, None]),
            (True, [1, 2, 4, 8]),
            (-1, [1, 2, 4, 8]),
            (0.1, [1, 2, 4, 8]),
            (1, [1, 2, 4, 8]),
            (1.9, [1, 2, 4, 8]),
            (2, [2, 4, 8, 16]),
        ],
    )
    def test_autoretry_backoff(self, retry_backoff, expected_countdowns):
        @self.app.task(bind=True, shared=False, autoretry_for=(ZeroDivisionError,),
                       retry_backoff=retry_backoff, retry_jitter=False, max_retries=3)
        def task(self_, x, y):
            self_.iterations += 1
            return x / y

        task.iterations = 0

        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, 0))

        assert task.iterations == 4
        retry_call_countdowns = [
            call_[1].get('countdown') for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == expected_countdowns

    @pytest.mark.parametrize(
        'retry_backoff, expected_countdowns',
        [
            (False, [None, None, None, None]),
            (0, [None, None, None, None]),
            (0.0, [None, None, None, None]),
            (True, [0, 1, 3, 7]),
            (-1, [0, 1, 3, 7]),
            (0.1, [0, 1, 3, 7]),
            (1, [0, 1, 3, 7]),
            (1.9, [0, 1, 3, 7]),
            (2, [1, 3, 7, 15]),
        ],
    )
    @patch('random.randrange', side_effect=lambda i: i - 2)
    def test_autoretry_backoff_jitter(self, randrange, retry_backoff, expected_countdowns):
        @self.app.task(bind=True, shared=False, autoretry_for=(HTTPError,),
                       retry_backoff=retry_backoff, retry_jitter=True, max_retries=3)
        def task(self_, url):
            self_.iterations += 1
            if "error" in url:
                fp = tempfile.TemporaryFile()
                raise HTTPError(url, '500', 'Error', '', fp)

        task.iterations = 0

        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply(("http://httpbin.org/error",))

        assert task.iterations == 4
        retry_call_countdowns = [
            call_[1].get('countdown') for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == expected_countdowns

    def test_autoretry_for_from_base(self):
        self.autoretry_for_from_base_task.iterations = 0
        self.autoretry_for_from_base_task.apply((1, "a"))
        assert self.autoretry_for_from_base_task.iterations == 6

    def test_override_autoretry_for_from_base(self):
        self.override_autoretry_for.iterations = 0
        self.override_autoretry_for.apply((1, 0))
        assert self.override_autoretry_for.iterations == 6

    def test_retry_kwargs_from_base(self):
        self.retry_kwargs_from_base_task.iterations = 0
        self.retry_kwargs_from_base_task.apply((1, "a"))
        assert self.retry_kwargs_from_base_task.iterations == 6

    def test_override_retry_kwargs_from_base(self):
        self.override_retry_kwargs.iterations = 0
        self.override_retry_kwargs.apply((1, "a"))
        assert self.override_retry_kwargs.iterations == 3

    def test_retry_backoff_from_base(self):
        task = self.retry_backoff_from_base_task
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [1, 2, 4, 8, 16, 32]

    @patch('celery.app.autoretry.get_exponential_backoff_interval')
    def test_override_retry_backoff_from_base(self, backoff):
        self.override_retry_backoff.iterations = 0
        self.override_retry_backoff.apply((1, "a"))
        assert self.override_retry_backoff.iterations == 6
        assert backoff.call_count == 0

    def test_retry_backoff_max_from_base(self):
        task = self.retry_backoff_max_from_base_task
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [1, 2, 4, 8, 16, 32]

    def test_override_retry_backoff_max_from_base(self):
        task = self.override_backoff_max
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [1, 2, 4, 8, 16, 16]

    def test_retry_backoff_jitter_from_base(self):
        task = self.retry_backoff_jitter_from_base
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [1, 2, 4, 8, 16, 32]

    @patch('random.randrange', side_effect=lambda i: i - 2)
    def test_override_backoff_jitter_from_base(self, randrange):
        task = self.override_backoff_jitter
        task.iterations = 0
        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, "a"))

        assert task.iterations == 6
        retry_call_countdowns = [
            call_[1]['countdown'] for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == [0, 1, 3, 7, 15, 31]

    def test_retry_wrong_eta_when_not_enable_utc(self):
        """Issue #3753"""
        self.app.conf.enable_utc = False
        self.app.conf.timezone = 'US/Eastern'
        self.autoretry_task.iterations = 0
        self.autoretry_task.default_retry_delay = 2

        self.autoretry_task.apply((1, 0))
        assert self.autoretry_task.iterations == 6

    @pytest.mark.parametrize(
        'backoff_value, expected_countdowns',
        [
            (False, [None, None, None]),
            (0, [None, None, None]),
            (0.0, [None, None, None]),
            (True, [1, 2, 4]),
            (-1, [1, 2, 4]),
            (0.1, [1, 2, 4]),
            (1, [1, 2, 4]),
            (1.9, [1, 2, 4]),
            (2, [2, 4, 8]),
        ],
    )
    def test_autoretry_class_based_task(self, backoff_value, expected_countdowns):
        class ClassBasedAutoRetryTask(Task):
            name = 'ClassBasedAutoRetryTask'
            autoretry_for = (ZeroDivisionError,)
            retry_kwargs = {'max_retries': 2}
            retry_backoff = backoff_value
            retry_backoff_max = 700
            retry_jitter = False
            iterations = 0
            _app = self.app

            def run(self, x, y):
                self.iterations += 1
                return x / y

        task = ClassBasedAutoRetryTask()
        self.app.tasks.register(task)
        task.iterations = 0

        with patch.object(task, 'retry', wraps=task.retry) as fake_retry:
            task.apply((1, 0))

        assert task.iterations == 3
        retry_call_countdowns = [
            call_[1].get('countdown') for call_ in fake_retry.call_args_list
        ]
        assert retry_call_countdowns == expected_countdowns


class test_canvas_utils(TasksCase):

    def test_si(self):
        assert self.retry_task.si()
        assert self.retry_task.si().immutable

    def test_chunks(self):
        assert self.retry_task.chunks(range(100), 10)

    def test_map(self):
        assert self.retry_task.map(range(100))

    def test_starmap(self):
        assert self.retry_task.starmap(range(100))

    def test_on_success(self):
        self.retry_task.on_success(1, 1, (), {})


class test_tasks(TasksCase):

    def now(self):
        return self.app.now()

    def test_typing(self):
        @self.app.task()
        def add(x, y, kw=1):
            pass

        with pytest.raises(TypeError):
            add.delay(1)

        with pytest.raises(TypeError):
            add.delay(1, kw=2)

        with pytest.raises(TypeError):
            add.delay(1, 2, foobar=3)

        add.delay(2, 2)

    def test_shadow_name(self):
        def shadow_name(task, args, kwargs, options):
            return 'fooxyz'

        @self.app.task(shadow_name=shadow_name)
        def shadowed():
            pass

        old_send_task = self.app.send_task
        self.app.send_task = Mock()

        shadowed.delay()

        self.app.send_task.assert_called_once_with(ANY, ANY, ANY,
                                                   compression=ANY,
                                                   delivery_mode=ANY,
                                                   exchange=ANY,
                                                   expires=ANY,
                                                   immediate=ANY,
                                                   link=ANY,
                                                   link_error=ANY,
                                                   mandatory=ANY,
                                                   priority=ANY,
                                                   producer=ANY,
                                                   queue=ANY,
                                                   result_cls=ANY,
                                                   routing_key=ANY,
                                                   serializer=ANY,
                                                   soft_time_limit=ANY,
                                                   task_id=ANY,
                                                   task_type=ANY,
                                                   time_limit=ANY,
                                                   shadow='fooxyz',
                                                   ignore_result=False)

        self.app.send_task = old_send_task

    def test_inherit_parent_priority_child_task(self):
        self.app.conf.task_inherit_parent_priority = True

        self.app.producer_or_acquire = Mock()
        self.app.producer_or_acquire.attach_mock(
            ContextMock(serializer='json'), 'return_value')
        self.app.amqp.send_task_message = Mock(name="send_task_message")

        self.task_which_calls_other_task.apply(args=[])

        self.app.amqp.send_task_message.assert_called_with(
            ANY, 't.unit.tasks.test_tasks.task_called_by_other_task',
            ANY, priority=5, queue=ANY, serializer=ANY)

    def test_typing__disabled(self):
        @self.app.task(typing=False)
        def add(x, y, kw=1):
            pass
        add.delay(1)
        add.delay(1, kw=2)
        add.delay(1, 2, foobar=3)

    def test_typing__disabled_by_app(self):
        with self.Celery(set_as_current=False, strict_typing=False) as app:
            @app.task()
            def add(x, y, kw=1):
                pass
            assert not add.typing
            add.delay(1)
            add.delay(1, kw=2)
            add.delay(1, 2, foobar=3)

    @pytest.mark.usefixtures('depends_on_current_app')
    def test_unpickle_task(self):
        import pickle

        @self.app.task(shared=True)
        def xxx():
            pass

        assert pickle.loads(pickle.dumps(xxx)) is xxx.app.tasks[xxx.name]

    @patch('celery.app.task.current_app')
    @pytest.mark.usefixtures('depends_on_current_app')
    def test_bind__no_app(self, current_app):

        class XTask(Task):
            _app = None

        XTask._app = None
        XTask.__bound__ = False
        XTask.bind = Mock(name='bind')
        assert XTask.app is current_app
        XTask.bind.assert_called_with(current_app)

    def test_reprtask__no_fmt(self):
        assert _reprtask(self.mytask)

    def test_AsyncResult(self):
        task_id = uuid()
        result = self.retry_task.AsyncResult(task_id)
        assert result.backend == self.retry_task.backend
        assert result.id == task_id

    def assert_next_task_data_equal(self, consumer, presult, task_name,
                                    test_eta=False, test_expires=False,
                                    properties=None, headers=None, **kwargs):
        next_task = consumer.queues[0].get(accept=['pickle', 'json'])
        task_properties = next_task.properties
        task_headers = next_task.headers
        task_body = next_task.decode()
        task_args, task_kwargs, embed = task_body
        assert task_headers['id'] == presult.id
        assert task_headers['task'] == task_name
        if test_eta:
            assert isinstance(task_headers.get('eta'), str)
            to_datetime = datetime.fromisoformat(task_headers.get('eta'))
            assert isinstance(to_datetime, datetime)
        if test_expires:
            assert isinstance(task_headers.get('expires'), str)
            to_datetime = datetime.fromisoformat(task_headers.get('expires'))
            assert isinstance(to_datetime, datetime)
        properties = properties or {}
        for arg_name, arg_value in properties.items():
            assert task_properties.get(arg_name) == arg_value
        headers = headers or {}
        for arg_name, arg_value in headers.items():
            assert task_headers.get(arg_name) == arg_value
        for arg_name, arg_value in kwargs.items():
            assert task_kwargs.get(arg_name) == arg_value

    def test_incomplete_task_cls(self):

        class IncompleteTask(Task):
            app = self.app
            name = 'c.unittest.t.itask'

        with pytest.raises(NotImplementedError):
            IncompleteTask().run()

    def test_task_kwargs_must_be_dictionary(self):
        with pytest.raises(TypeError):
            self.increment_counter.apply_async([], 'str')

    def test_task_args_must_be_list(self):
        with pytest.raises(TypeError):
            self.increment_counter.apply_async('s', {})

    def test_regular_task(self):
        assert isinstance(self.mytask, Task)
        assert self.mytask.run()
        assert callable(self.mytask)
        assert self.mytask(), 'Task class runs run() when called'

        with self.app.connection_or_acquire() as conn:
            consumer = self.app.amqp.TaskConsumer(conn)
            with pytest.raises(NotImplementedError):
                consumer.receive('foo', 'foo')
            consumer.purge()
            assert consumer.queues[0].get() is None
            self.app.amqp.TaskConsumer(conn, queues=[Queue('foo')])

            # Without arguments.
            presult = self.mytask.delay()
            self.assert_next_task_data_equal(
                consumer, presult, self.mytask.name)

            # With arguments.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name, name='George Costanza',
            )

            # send_task
            sresult = self.app.send_task(self.mytask.name,
                                         kwargs={'name': 'Elaine M. Benes'})
            self.assert_next_task_data_equal(
                consumer, sresult, self.mytask.name, name='Elaine M. Benes',
            )

            # With ETA, absolute expires.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
                eta=self.now() + timedelta(days=1),
                expires=self.now() + timedelta(days=2),
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # With ETA, absolute expires without timezone.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Constanza'},
                eta=self.now() + timedelta(days=1),
                expires=(self.now() + timedelta(hours=2)).replace(tzinfo=None),
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Constanza', test_eta=True, test_expires=True,
            )

            # With ETA, absolute expires in the past.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
                eta=self.now() + timedelta(days=1),
                expires=self.now() - timedelta(days=2),
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # With ETA, relative expires.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
                eta=self.now() + timedelta(days=1),
                expires=2 * 24 * 60 * 60,
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # With countdown.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'}, countdown=10, expires=12,
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # With ETA, absolute expires in the past in ISO format.
            presult2 = self.mytask.apply_async(
                kwargs={'name': 'George Costanza'},
                eta=self.now() + timedelta(days=1),
                expires=self.now() - timedelta(days=2),
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                name='George Costanza', test_eta=True, test_expires=True,
            )

            # Default argsrepr/kwargsrepr behavior
            presult2 = self.mytask.apply_async(
                args=('spam',), kwargs={'name': 'Jerry Seinfeld'}
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                headers={'argsrepr': "('spam',)",
                         'kwargsrepr': "{'name': 'Jerry Seinfeld'}"},
            )

            # With argsrepr/kwargsrepr
            presult2 = self.mytask.apply_async(
                args=('secret',), argsrepr="'***'",
                kwargs={'password': 'foo'}, kwargsrepr="{'password': '***'}",
            )
            self.assert_next_task_data_equal(
                consumer, presult2, self.mytask.name,
                headers={'argsrepr': "'***'",
                         'kwargsrepr': "{'password': '***'}"},
            )

            # Discarding all tasks.
            consumer.purge()
            self.mytask.apply_async()
            assert consumer.purge() == 1
            assert consumer.queues[0].get() is None

            assert not presult.successful()
            self.mytask.backend.mark_as_done(presult.id, result=None)
            assert presult.successful()

    def test_send_event(self):
        mytask = self.mytask._get_current_object()
        mytask.app.events = Mock(name='events')
        mytask.app.events.attach_mock(ContextMock(), 'default_dispatcher')
        mytask.request.id = 'fb'
        mytask.send_event('task-foo', id=3122)
        mytask.app.events.default_dispatcher().send.assert_called_with(
            'task-foo', uuid='fb', id=3122,
            retry=True, retry_policy=self.app.conf.task_publish_retry_policy)

    @pytest.mark.usefixtures('depends_on_current_app')
    def test_on_replace(self):
        class CustomStampingVisitor(StampingVisitor):
            def on_signature(self, sig, **headers) -> dict:
                return {'header': 'value'}

        class MyTask(Task):
            def on_replace(self, sig):
                sig.stamp(CustomStampingVisitor())
                return super().on_replace(sig)

        mytask = self.app.task(shared=False, base=MyTask)(return_True)

        sig1 = signature('sig1')
        with pytest.raises(Ignore):
            mytask.replace(sig1)
        assert sig1.options['header'] == 'value'

    def test_replace(self):
        sig1 = MagicMock(name='sig1')
        sig1.options = {}
        self.mytask.request.id = sentinel.request_id
        with pytest.raises(Ignore):
            self.mytask.replace(sig1)
        sig1.freeze.assert_called_once_with(self.mytask.request.id)
        sig1.set.assert_called_once_with(replaced_task_nesting=1,
                                         chord=ANY,
                                         group_id=ANY,
                                         group_index=ANY,
                                         root_id=ANY)

    def test_replace_with_chord(self):
        sig1 = Mock(name='sig1')
        sig1.options = {'chord': None}
        with pytest.raises(ImproperlyConfigured):
            self.mytask.replace(sig1)

    def test_replace_callback(self):
        c = group([self.mytask.s()], app=self.app)
        c.freeze = Mock(name='freeze')
        c.delay = Mock(name='delay')
        self.mytask.request.id = 'id'
        self.mytask.request.group = 'group'
        self.mytask.request.root_id = 'root_id'
        self.mytask.request.callbacks = callbacks = 'callbacks'
        self.mytask.request.errbacks = errbacks = 'errbacks'

        # Replacement groups get uplifted to chords so that we can accumulate
        # the results and link call/errbacks - patch the appropriate `chord`
        # methods so we can validate this behaviour
        with patch(
            "celery.canvas.chord.link"
        ) as mock_chord_link, patch(
            "celery.canvas.chord.link_error"
        ) as mock_chord_link_error:
            with pytest.raises(Ignore):
                self.mytask.replace(c)
        # Confirm that the call/errbacks on the original signature are linked
        # to the replacement signature as expected
        mock_chord_link.assert_called_once_with(callbacks)
        mock_chord_link_error.assert_called_once_with(errbacks)

    def test_replace_group(self):
        c = group([self.mytask.s()], app=self.app)
        c.freeze = Mock(name='freeze')
        c.delay = Mock(name='delay')
        self.mytask.request.id = 'id'
        self.mytask.request.group = 'group'
        self.mytask.request.root_id = 'root_id',
        with pytest.raises(Ignore):
            self.mytask.replace(c)

    def test_replace_chain(self):
        c = chain([self.mytask.si(), self.mytask.si()], app=self.app)
        c.freeze = Mock(name='freeze')
        c.delay = Mock(name='delay')
        self.mytask.request.id = 'id'
        self.mytask.request.chain = c
        with pytest.raises(Ignore):
            self.mytask.replace(c)

    def test_replace_run(self):
        with pytest.raises(Ignore):
            self.task_replaced_by_other_task.run()

    def test_replace_run_with_autoretry(self):
        with pytest.raises(Ignore):
            self.task_replaced_by_other_task_with_autoretry.run()

    def test_replace_delay(self):
        res = self.task_replaced_by_other_task.delay()
        assert isinstance(res, AsyncResult)

    def test_replace_apply(self):
        res = self.task_replaced_by_other_task.apply()
        assert isinstance(res, EagerResult)
        assert res.get() == "replaced"

    def test_add_trail__no_trail(self):
        mytask = self.increment_counter._get_current_object()
        mytask.trail = False
        mytask.add_trail('foo')

    def test_repr_v2_compat(self):
        self.mytask.__v2_compat__ = True
        assert 'v2 compatible' in repr(self.mytask)

    def test_context_get(self):
        self.mytask.push_request()
        try:
            request = self.mytask.request
            request.foo = 32
            assert request.get('foo') == 32
            assert request.get('bar', 36) == 36
            request.clear()
        finally:
            self.mytask.pop_request()

    def test_annotate(self):
        with patch('celery.app.task.resolve_all_annotations') as anno:
            anno.return_value = [{'FOO': 'BAR'}]

            @self.app.task(shared=False)
            def task():
                pass

            task.annotate()
            assert task.FOO == 'BAR'

    def test_after_return(self):
        self.mytask.push_request()
        try:
            self.mytask.request.chord = self.mytask.s()
            self.mytask.after_return('SUCCESS', 1.0, 'foobar', (), {}, None)
            self.mytask.request.clear()
        finally:
            self.mytask.pop_request()

    def test_update_state(self):

        @self.app.task(shared=False)
        def yyy():
            pass

        yyy.push_request()
        try:
            tid = uuid()
            # update_state should accept arbitrary kwargs, which are passed to
            # the backend store_result method
            yyy.update_state(tid, 'FROBULATING', {'fooz': 'baaz'},
                             arbitrary_kwarg=None)
            assert yyy.AsyncResult(tid).status == 'FROBULATING'
            assert yyy.AsyncResult(tid).result == {'fooz': 'baaz'}

            yyy.request.id = tid
            yyy.update_state(state='FROBUZATING', meta={'fooz': 'baaz'})
            assert yyy.AsyncResult(tid).status == 'FROBUZATING'
            assert yyy.AsyncResult(tid).result == {'fooz': 'baaz'}
        finally:
            yyy.pop_request()

    def test_update_state_passes_request_to_backend(self):
        backend = Mock()

        @self.app.task(shared=False, backend=backend)
        def ttt():
            pass

        ttt.push_request()

        tid = uuid()
        ttt.update_state(tid, 'SHRIMMING', {'foo': 'bar'})

        backend.store_result.assert_called_once_with(
            tid, {'foo': 'bar'}, 'SHRIMMING', request=ttt.request
        )

    def test_repr(self):

        @self.app.task(shared=False)
        def task_test_repr():
            pass

        assert 'task_test_repr' in repr(task_test_repr)

    def test_has___name__(self):

        @self.app.task(shared=False)
        def yyy2():
            pass

        assert yyy2.__name__

    def test_default_priority(self):

        @self.app.task(shared=False)
        def yyy3():
            pass

        @self.app.task(shared=False, priority=66)
        def yyy4():
            pass

        @self.app.task(shared=False, bind=True, base=TaskWithPriority)
        def yyy5(self):
            pass

        self.app.conf.task_default_priority = 42
        old_send_task = self.app.send_task

        self.app.send_task = Mock()
        yyy3.delay()
        self.app.send_task.assert_called_once_with(ANY, ANY, ANY,
                                                   compression=ANY,
                                                   delivery_mode=ANY,
                                                   exchange=ANY,
                                                   expires=ANY,
                                                   immediate=ANY,
                                                   link=ANY,
                                                   link_error=ANY,
                                                   mandatory=ANY,
                                                   priority=42,
                                                   producer=ANY,
                                                   queue=ANY,
                                                   result_cls=ANY,
                                                   routing_key=ANY,
                                                   serializer=ANY,
                                                   soft_time_limit=ANY,
                                                   task_id=ANY,
                                                   task_type=ANY,
                                                   time_limit=ANY,
                                                   shadow=None,
                                                   ignore_result=False)

        self.app.send_task = Mock()
        yyy4.delay()
        self.app.send_task.assert_called_once_with(ANY, ANY, ANY,
                                                   compression=ANY,
                                                   delivery_mode=ANY,
                                                   exchange=ANY,
                                                   expires=ANY,
                                                   immediate=ANY,
                                                   link=ANY,
                                                   link_error=ANY,
                                                   mandatory=ANY,
                                                   priority=66,
                                                   producer=ANY,
                                                   queue=ANY,
                                                   result_cls=ANY,
                                                   routing_key=ANY,
                                                   serializer=ANY,
                                                   soft_time_limit=ANY,
                                                   task_id=ANY,
                                                   task_type=ANY,
                                                   time_limit=ANY,
                                                   shadow=None,
                                                   ignore_result=False)

        self.app.send_task = Mock()
        yyy5.delay()
        self.app.send_task.assert_called_once_with(ANY, ANY, ANY,
                                                   compression=ANY,
                                                   delivery_mode=ANY,
                                                   exchange=ANY,
                                                   expires=ANY,
                                                   immediate=ANY,
                                                   link=ANY,
                                                   link_error=ANY,
                                                   mandatory=ANY,
                                                   priority=10,
                                                   producer=ANY,
                                                   queue=ANY,
                                                   result_cls=ANY,
                                                   routing_key=ANY,
                                                   serializer=ANY,
                                                   soft_time_limit=ANY,
                                                   task_id=ANY,
                                                   task_type=ANY,
                                                   time_limit=ANY,
                                                   shadow=None,
                                                   ignore_result=False)

        self.app.send_task = old_send_task


class test_apply_task(TasksCase):

    def test_apply_throw(self):
        with pytest.raises(KeyError):
            self.raising.apply(throw=True)

    def test_apply_with_task_eager_propagates(self):
        self.app.conf.task_eager_propagates = True
        with pytest.raises(KeyError):
            self.raising.apply()

    def test_apply_request_context_is_ok(self):
        self.app.conf.task_eager_propagates = True
        self.task_check_request_context.apply()

    def test_apply(self):
        self.increment_counter.count = 0

        e = self.increment_counter.apply()
        assert isinstance(e, EagerResult)
        assert e.get() == 1

        e = self.increment_counter.apply(args=[1])
        assert e.get() == 2

        e = self.increment_counter.apply(kwargs={'increment_by': 4})
        assert e.get() == 6

        assert e.successful()
        assert e.ready()
        assert repr(e).startswith('<EagerResult:')

        f = self.raising.apply()
        assert f.ready()
        assert not f.successful()
        assert f.traceback
        with pytest.raises(KeyError):
            f.get()

    def test_apply_simulates_delivery_info(self):
        task_to_apply = self.task_check_request_context
        with patch.object(
            task_to_apply.request_stack, "push",
            wraps=task_to_apply.request_stack.push,
        ) as mock_push:
            task_to_apply.apply(
                priority=4,
                routing_key='myroutingkey',
                exchange='myexchange',
            )

        mock_push.assert_called_once()

        request = mock_push.call_args[0][0]

        assert request.delivery_info == {
            'is_eager': True,
            'exchange': 'myexchange',
            'routing_key': 'myroutingkey',
            'priority': 4,
        }


class test_apply_async(TasksCase):
    def common_send_task_arguments(self):
        return (ANY, ANY, ANY), dict(
            compression=ANY,
            delivery_mode=ANY,
            exchange=ANY,
            expires=ANY,
            immediate=ANY,
            link=ANY,
            link_error=ANY,
            mandatory=ANY,
            priority=ANY,
            producer=ANY,
            queue=ANY,
            result_cls=ANY,
            routing_key=ANY,
            serializer=ANY,
            soft_time_limit=ANY,
            task_id=ANY,
            task_type=ANY,
            time_limit=ANY,
            shadow=None,
            ignore_result=False
        )

    def test_eager_serialization_failure(self):
        @self.app.task
        def task(*args, **kwargs):
            pass
        with pytest.raises(EncodeError):
            task.apply_async((1, 2, 3, 4, {1}))

    def test_eager_serialization_uses_task_serializer_setting(self):
        @self.app.task
        def task(*args, **kwargs):
            pass
        with pytest.raises(EncodeError):
            task.apply_async((1, 2, 3, 4, {1}))

        self.app.conf.task_serializer = 'pickle'

        @self.app.task
        def task2(*args, **kwargs):
            pass
        task2.apply_async((1, 2, 3, 4, {1}))

    def test_always_eager_with_task_serializer_option(self):
        self.app.conf.task_always_eager = True
        self.app.conf.task_serializer = 'pickle'

        @self.app.task
        def task(*args, **kwargs):
            pass
        task.apply_async((1, 2, 3, 4, {1}))

    def test_always_eager_uses_task_serializer_setting(self):
        self.app.conf.task_always_eager = True

        @self.app.task(serializer='pickle')
        def task(*args, **kwargs):
            pass
        task.apply_async((1, 2, 3, 4, {1}))

    def test_task_with_ignored_result(self):
        with patch.object(self.app, 'send_task') as send_task:
            self.task_with_ignored_result.apply_async()
            expected_args, expected_kwargs = self.common_send_task_arguments()
            expected_kwargs['ignore_result'] = True
            send_task.assert_called_once_with(
                *expected_args,
                **expected_kwargs
            )

    def test_task_with_result(self):
        with patch.object(self.app, 'send_task') as send_task:
            self.mytask.apply_async()
            expected_args, expected_kwargs = self.common_send_task_arguments()
            send_task.assert_called_once_with(
                *expected_args,
                **expected_kwargs
            )

    def test_task_with_result_ignoring_on_call(self):
        with patch.object(self.app, 'send_task') as send_task:
            self.mytask.apply_async(ignore_result=True)
            expected_args, expected_kwargs = self.common_send_task_arguments()
            expected_kwargs['ignore_result'] = True
            send_task.assert_called_once_with(
                *expected_args,
                **expected_kwargs
            )
