"unittest.mock" --- mock object library
***************************************

Ajouté dans la version 3.3.

**Code source :** Lib/unittest/mock.py

======================================================================

"unittest.mock" est une bibliothèque pour tester en Python. Elle
permet de remplacer des parties du système sous tests par des objets
simulacres et faire des assertions sur la façon dont ces objets ont
été utilisés.

"unittest.mock" fournit une classe "Mock" pour ne pas avoir besoin de
créer manuellement des objets factices dans la suite de tests. Après
avoir effectué une action, on peut faire des assertions sur les
méthodes / attributs utilisés et les arguments avec lesquels ils ont
été appelés. On peut également spécifier des valeurs renvoyées et
définir les attributs nécessaires aux tests.

De plus, *mock* fournit un décorateur "patch()" qui est capable de
*patcher* les modules et les classes dans la portée d'un test, ainsi
que "sentinel" pour créer des objets uniques. Voir le guide rapide
quick guide pour quelques exemples d'utilisation de "Mock",
"MagicMock" et "patch()".

Mock is designed for use with "unittest" and is based on the 'action
-> assertion' pattern instead of 'record -> replay' used by many
mocking frameworks.

There is a backport of "unittest.mock" for earlier versions of Python,
available as mock on PyPI.


Guide rapide
============

Les classes "Mock" et "MagicMock" créent tous les attributs et
méthodes au fur et à mesure des accès et stockent les détails de la
façon dont ils ont été utilisés. On peut les configurer, pour
spécifier des valeurs de renvoi ou limiter les attributs utilisables,
puis faire des assertions sur la façon dont ils ont été utilisés :

>>> from unittest.mock import MagicMock
>>> thing = ProductionClass()
>>> thing.method = MagicMock(return_value=3)
>>> thing.method(3, 4, 5, key='value')
3
>>> thing.method.assert_called_with(3, 4, 5, key='value')

"side_effect" allows you to perform side effects, including raising an
exception when a mock is called:

>>> from unittest.mock import Mock
>>> mock = Mock(side_effect=KeyError('foo'))
>>> mock()
Traceback (most recent call last):
 ...
KeyError: 'foo'

>>> values = {'a': 1, 'b': 2, 'c': 3}
>>> def side_effect(arg):
...     return values[arg]
...
>>> mock.side_effect = side_effect
>>> mock('a'), mock('b'), mock('c')
(1, 2, 3)
>>> mock.side_effect = [5, 4, 3, 2, 1]
>>> mock(), mock(), mock()
(5, 4, 3)

Il existe beaucoup d'autres façons de configurer et de contrôler le
comportement de *Mock*. Par exemple, l'argument *spec* configure le
*mock* pour qu'il utilise les spécifications d'un autre objet. Tenter
d'accéder à des attributs ou méthodes sur le *mock* qui n'existent pas
sur l'objet *spec* lève une "AttributeError".

The "patch()" decorator / context manager makes it easy to mock
classes or objects in a module under test. The object you specify will
be replaced with a mock (or other object) during the test and restored
when the test ends:

   >>> from unittest.mock import patch
   >>> @patch('module.ClassName2')
   ... @patch('module.ClassName1')
   ... def test(MockClass1, MockClass2):
   ...     module.ClassName1()
   ...     module.ClassName2()
   ...     assert MockClass1 is module.ClassName1
   ...     assert MockClass2 is module.ClassName2
   ...     assert MockClass1.called
   ...     assert MockClass2.called
   ...
   >>> test()

Note:

  Lorsque l'on imbrique des décorateurs de patchs, les *mocks* sont
  transmis à la fonction décorée dans le même ordre qu'ils ont été
  déclarés (l'ordre normal *Python* des décorateurs est appliqué).
  Cela signifie du bas vers le haut, donc dans l'exemple ci-dessus,
  l'objet simulacre pour "module.ClassName1" est passé en premier.Avec
  "patch()", il est important de *patcher* les objets dans l'espace de
  nommage où ils sont recherchés. C'est ce qui se fait normalement,
  mais pour un guide rapide, lisez où patcher.

Comme tout décorateur, "patch()" peut être utilisé comme gestionnaire
de contexte avec une instruction *with* :

>>> with patch.object(ProductionClass, 'method', return_value=None) as mock_method:
...     thing = ProductionClass()
...     thing.method(1, 2, 3)
...
>>> mock_method.assert_called_once_with(1, 2, 3)

Il existe également "patch.dict()" pour définir des valeurs d'un
dictionnaire au sein d'une portée et restaurer ce dictionnaire à son
état d'origine lorsque le test se termine :

>>> foo = {'key': 'value'}
>>> original = foo.copy()
>>> with patch.dict(foo, {'newkey': 'newvalue'}, clear=True):
...     assert foo == {'newkey': 'newvalue'}
...
>>> assert foo == original

*Mock* gère le remplacement des méthodes magiques de Python. La façon
la plus simple d'utiliser les méthodes magiques est la classe
"MagicMock". Elle permet de faire des choses comme :

>>> mock = MagicMock()
>>> mock.__str__.return_value = 'foobarbaz'
>>> str(mock)
'foobarbaz'
>>> mock.__str__.assert_called_with()

*Mock* permet d'assigner des fonctions (ou d'autres instances *Mock*)
à des méthodes magiques et elles seront appelées correctement. La
classe "MagicMock" est juste une variante de *Mock* qui a toutes les
méthodes magiques pré-créées (enfin, toutes les méthodes utiles).

L'exemple suivant est un exemple de création de méthodes magiques avec
la classe *Mock* ordinaire :

>>> mock = Mock()
>>> mock.__str__ = Mock(return_value='wheeeeee')
>>> str(mock)
'wheeeeee'

Pour être sûr que les objets simulacres dans vos tests ont la même API
que les objets qu'ils remplacent, utilisez l'auto-spécification. L
'auto-spécification peut se faire via l'argument *autospec* de patch
ou par la fonction "create_autospec()". L'auto-spécification crée des
objets simulacres qui ont les mêmes attributs et méthodes que les
objets qu'ils remplacent, et toutes les fonctions et méthodes (y
compris les constructeurs) ont les mêmes signatures d'appel que
l'objet réel.

Ceci garantit que vos objets simulacres échouent de la même manière
que votre code de production s'ils ne sont pas utilisés correctement :

>>> from unittest.mock import create_autospec
>>> def function(a, b, c):
...     pass
...
>>> mock_function = create_autospec(function, return_value='fishy')
>>> mock_function(1, 2, 3)
'fishy'
>>> mock_function.assert_called_once_with(1, 2, 3)
>>> mock_function('wrong arguments')
Traceback (most recent call last):
 ...
TypeError: missing a required argument: 'b'

La fonction "create_autospec()" peut aussi être utilisée sur les
classes, où elle copie la signature de la méthode "__init__", et sur
les objets appelables où elle copie la signature de la méthode
"__call__".


La classe *Mock*
================

La classe "Mock" est un objet simulacre flexible destiné à remplacer
l'utilisation d'objets bouchons et factices dans votre code. Les Mocks
sont appelables et créent des attributs comme de nouveaux *Mocks*
lorsque l'on y accède [1]. L'accès au même attribut renvoie toujours
le même *mock*. Les simulacres enregistrent la façon dont ils sont
utilisés, ce qui permet de faire des assertions sur ce que le code
leur a fait.

La classe "MagicMock" est une sous-classe de "Mock" avec toutes les
méthodes magiques pré-créées et prête à l'emploi. Il existe également
des variantes non appelables, utiles lorsque l'on simule des objets
qui ne sont pas appelables : "NonCallableMock" et
"NonCallableMagicMock"

Le décorateur "patch()" facilite le remplacement temporaire de classes
d'un module avec un objet "Mock". Par défaut "patch()" crée un
"MagicMock". On peut spécifier une classe alternative de "Mock" en
utilisant le paramètre *new_callable* de "patch()".

class unittest.mock.Mock(spec=None, side_effect=None, return_value=DEFAULT, wraps=None, name=None, spec_set=None, unsafe=False, **kwargs)

   Crée un nouvel objet "Mock". "Mock" prend plusieurs arguments
   optionnels qui spécifient le comportement de l'objet *Mock* :

   * *spec* : une liste de chaînes de caractères ou un objet existant
     (une classe ou une instance) qui sert de spécification pour
     l'objet simulacre. Si on passe un objet, alors une liste de
     chaînes de caractères est formée en appelant la fonction *dir*
     sur l'objet (à l'exclusion des attributs et méthodes magiques non
     pris en charge). L'accès à un attribut qui n'est pas dans cette
     liste entraîne la levée d'une exception "AttributeError".

     If *spec* is an object (rather than a list of strings) then
     "__class__" returns the class of the spec object. This allows
     mocks to pass "isinstance()" tests.

   * *spec_set* : variante plus stricte de *spec*. S'il est utilisé,
     essayer d'utiliser la fonction *set* ou tenter d’accéder à un
     attribut sur le *mock* qui n'est pas sur l'objet passé comme
     *spec_set* lève une exception "AttributeError".

   * *side_effect* : fonction à appeler à chaque fois que le *Mock*
     est appelé. Voir l'attribut "side_effect". Utile pour lever des
     exceptions ou modifier dynamiquement les valeurs de retour. La
     fonction est appelée avec les mêmes arguments que la fonction
     simulée et, à moins qu'elle ne renvoie "DEFAULT", la valeur de
     retour de cette fonction devient la valeur de retour de la
     fonction simulée.

     *side_effect* peut être soit une classe, soit une instance
     d'exception. Dans ce cas, l'exception est levée lors de l'appel
     de l'objet simulacre.

     Si *side_effect* est un itérable alors chaque appel au *mock*
     renvoie la valeur suivante de l’itérable.

     Utilisez "None" pour remettre à zéro un *side_effect*.

   * *return_value* : valeur renvoyée lors de l'appel de l'objet
     simulacre. Par défaut, il s'agit d'un nouveau *Mock* (créé lors
     du premier accès). Voir l'attribut "return_value".

   * *unsafe*: By default, accessing any attribute whose name starts
     with *assert*, *assret*, *asert*, *aseert* or *assrt* will raise
     an "AttributeError". Passing "unsafe=True" will allow access to
     these attributes.

     Ajouté dans la version 3.5.

   * *wraps* : élément que le simulacre doit simuler. Si *wraps* n'est
     pas "None" alors appeler *Mock* passe l'appel à l'objet simulé
     (renvoyant le résultat réel). L'accès à un attribut sur le *mock*
     renvoie un objet *Mock* qui simule l'attribut correspondant de
     l'objet simulé (donc essayer d'accéder à un attribut qui n'existe
     pas lève une exception "AttributeError").

     Si l'objet simulacre a un ensemble explicite de *return_value*
     alors les appels ne sont pas passés à l'objet simulé et c'est
     *return_value* qui est renvoyée à la place.

   * *name* : Si le *mock* a un nom, il est alors utilisé par la
     fonction *repr* du *mock*. C'est utile pour le débogage. Le nom
     est propagé aux enfants de l'objet *mock*.

   Les *mocks* peuvent aussi être appelés avec des arguments par mots-
   clés arbitraires. Ceux-ci sont utilisés pour définir les attributs
   sur le *mock* après sa création. Voir la méthode "configure_mock()"
   pour plus de détails.

   assert_called()

      Asserter que le *mock* a été appelé au moins une fois.

      >>> mock = Mock()
      >>> mock.method()
      <Mock name='mock.method()' id='...'>
      >>> mock.method.assert_called()

      Ajouté dans la version 3.6.

   assert_called_once()

      Asserter que le *mock* a été appelé exactement une fois.

      >>> mock = Mock()
      >>> mock.method()
      <Mock name='mock.method()' id='...'>
      >>> mock.method.assert_called_once()
      >>> mock.method()
      <Mock name='mock.method()' id='...'>
      >>> mock.method.assert_called_once()
      Traceback (most recent call last):
      ...
      AssertionError: Expected 'method' to have been called once. Called 2 times.
      Calls: [call(), call()].

      Ajouté dans la version 3.6.

   assert_called_with(*args, **kwargs)

      This method is a convenient way of asserting that the last call
      has been made in a particular way:

      >>> mock = Mock()
      >>> mock.method(1, 2, 3, test='wow')
      <Mock name='mock.method()' id='...'>
      >>> mock.method.assert_called_with(1, 2, 3, test='wow')

   assert_called_once_with(*args, **kwargs)

      Assert that the mock was called exactly once and that call was
      with the specified arguments.

      >>> mock = Mock(return_value=None)
      >>> mock('foo', bar='baz')
      >>> mock.assert_called_once_with('foo', bar='baz')
      >>> mock('other', bar='values')
      >>> mock.assert_called_once_with('other', bar='values')
      Traceback (most recent call last):
        ...
      AssertionError: Expected 'mock' to be called once. Called 2 times.
      Calls: [call('foo', bar='baz'), call('other', bar='values')].

   assert_any_call(*args, **kwargs)

      Asserter que le simulacre a été appelé avec les arguments
      spécifiés.

      Asserter que le simulacre a *bien* été appelé avec les arguments
      au cours de la vie du simulacre. Contrairement à
      "assert_called_with()" et "assert_called_once_with()" qui
      passent seulement si l'appel demandé correspond bien au dernier
      appel, et dans le cas de "assert_called_once_with()" l'appel au
      simulacre doit être unique.

      >>> mock = Mock(return_value=None)
      >>> mock(1, 2, arg='thing')
      >>> mock('some', 'thing', 'else')
      >>> mock.assert_any_call(1, 2, arg='thing')

   assert_has_calls(calls, any_order=False)

      Asserter que le simulacre a été appelé avec les appels
      spécifiés. L'attribut "mock_calls" est comparé à la liste des
      appels.

      If *any_order* is false then the calls must be sequential. There
      can be extra calls before or after the specified calls.

      Si *any_order* est vrai alors les appels peuvent être dans
      n'importe quel ordre, mais ils doivent tous apparaître dans
      "mock_calls".

      >>> mock = Mock(return_value=None)
      >>> mock(1)
      >>> mock(2)
      >>> mock(3)
      >>> mock(4)
      >>> calls = [call(2), call(3)]
      >>> mock.assert_has_calls(calls)
      >>> calls = [call(4), call(2), call(3)]
      >>> mock.assert_has_calls(calls, any_order=True)

   assert_not_called()

      Asserter que le simulacre n'a jamais été appelé.

      >>> m = Mock()
      >>> m.hello.assert_not_called()
      >>> obj = m.hello()
      >>> m.hello.assert_not_called()
      Traceback (most recent call last):
        ...
      AssertionError: Expected 'hello' to not have been called. Called 1 times.
      Calls: [call()].

      Ajouté dans la version 3.5.

   reset_mock(*, return_value=False, side_effect=False)

      La méthode *reset_mock* réinitialise tous les attributs d'appel
      sur un simulacre :

         >>> mock = Mock(return_value=None)
         >>> mock('hello')
         >>> mock.called
         True
         >>> mock.reset_mock()
         >>> mock.called
         False

      This can be useful where you want to make a series of assertions
      that reuse the same object.

      *return_value* parameter when set to "True" resets
      "return_value":

         >>> mock = Mock(return_value=5)
         >>> mock('hello')
         5
         >>> mock.reset_mock(return_value=True)
         >>> mock('hello')  
         <Mock name='mock()' id='...'>

      *side_effect* parameter when set to "True" resets "side_effect":

         >>> mock = Mock(side_effect=ValueError)
         >>> mock('hello')
         Traceback (most recent call last):
           ...
         ValueError
         >>> mock.reset_mock(side_effect=True)
         >>> mock('hello')  
         <Mock name='mock()' id='...'>

      Note that "reset_mock()" *doesn't* clear the "return_value",
      "side_effect" or any child attributes you have set using normal
      assignment by default.

      Child mocks are reset as well.

      Modifié dans la version 3.6: Added two keyword-only arguments to
      the reset_mock function.

   mock_add_spec(spec, spec_set=False)

      Ajoute une spécification à un simulacre. *spec* peut être un
      objet ou une liste de chaînes de caractères. Seuls les attributs
      de la spécification *spec* peuvent être récupérés en tant
      qu'attributs du simulacre.

      Si *spec_set* est vrai, seuls les attributs de la spécification
      peuvent être définis.

   attach_mock(mock, attribute)

      Attache un simulacre comme attribut de l'instance courante, en
      remplaçant son nom et son parent. Les appels au simulacre
      attaché sont enregistrés dans les attributs "method_calls" et
      "mock_calls" de l'instance courante.

   configure_mock(**kwargs)

      Définir les attributs sur le simulacre à l'aide d'arguments
      nommés.

      Les attributs, les valeurs de retour et les effets de bords
      peuvent être définis sur des simulacres enfants en utilisant la
      notation par points standard et en dépaquetant un dictionnaire
      dans l'appel de méthode :

      >>> mock = Mock()
      >>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
      >>> mock.configure_mock(**attrs)
      >>> mock.method()
      3
      >>> mock.other()
      Traceback (most recent call last):
        ...
      KeyError

      La même chose peut être réalisée en utilisant le constructeur
      des simulacres :

      >>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
      >>> mock = Mock(some_attribute='eggs', **attrs)
      >>> mock.some_attribute
      'eggs'
      >>> mock.method()
      3
      >>> mock.other()
      Traceback (most recent call last):
        ...
      KeyError

      "configure_mock()" existe pour faciliter la configuration après
      la création du simulacre.

   __dir__()

      Les objets "Mock" limitent les résultats de "dir(un_mock)" à des
      résultats utiles. Pour les simulacres avec une spécification
      *spec*, cela inclut tous les attributs autorisés du simulacre.

      Voir "FILTER_DIR" pour savoir ce que fait ce filtrage, et
      comment le désactiver.

   _get_child_mock(**kw)

      Crée les simulacres enfants pour les attributs et la valeur de
      retour. Par défaut, les objets simulacre enfants sont du même
      type que le parent. Les sous-classes de *Mock* peuvent
      surcharger cette méthode pour personnaliser la façon dont les
      simulacres enfants sont créés.

      Pour les simulacres non appelables, la variante appelable est
      utilisée (plutôt qu'une sous-classe personnalisée).

   called

      Un booléen représentant si le simulacre a bien été appelé ou non
      :

      >>> mock = Mock(return_value=None)
      >>> mock.called
      False
      >>> mock()
      >>> mock.called
      True

   call_count

      Un entier indiquant combien de fois le simulacre a été appelé :

      >>> mock = Mock(return_value=None)
      >>> mock.call_count
      0
      >>> mock()
      >>> mock()
      >>> mock.call_count
      2

   return_value

      Définir cette option pour configurer la valeur renvoyé par appel
      du simulacre :

      >>> mock = Mock()
      >>> mock.return_value = 'fish'
      >>> mock()
      'fish'

      La valeur de revoie par défaut est un simulacre configurable
      normalement :

      >>> mock = Mock()
      >>> mock.return_value.attribute = sentinel.Attribute
      >>> mock.return_value()
      <Mock name='mock()()' id='...'>
      >>> mock.return_value.assert_called_with()

      L'attribut "return_value" peut également être défini dans le
      constructeur :

      >>> mock = Mock(return_value=3)
      >>> mock.return_value
      3
      >>> mock()
      3

   side_effect

      C'est soit une fonction à appeler lors de l'appel du simulacre,
      soit une exception (classe ou instance) à lever.

      Si vous passez une fonction, elle est appelée avec les mêmes
      arguments que la fonction simulée et à moins que la fonction ne
      renvoie le singleton "DEFAULT" l'appel le la fonction simulée
      renvoie ce que la fonction renvoie. Si la fonction renvoie
      "DEFAULT" alors le simulacre renvoie sa valeur normale (celle de
      "return_value").

      Si vous passez un itérable, il est utilisé pour récupérer un
      itérateur qui doit renvoyer une valeur à chaque appel. Cette
      valeur peut être soit une instance d'exception à lever, soit une
      valeur à renvoyer à l'appel au simulacre (le traitement
      "DEFAULT" est identique au renvoie de la fonction simulée).

      Un exemple d'un simulacre qui lève une exception (pour tester la
      gestion des exceptions d'une API) :

      >>> mock = Mock()
      >>> mock.side_effect = Exception('Boom!')
      >>> mock()
      Traceback (most recent call last):
        ...
      Exception: Boom!

      Utiliser "side_effect" pour renvoyer une séquence de valeurs :

      >>> mock = Mock()
      >>> mock.side_effect = [3, 2, 1]
      >>> mock(), mock(), mock()
      (3, 2, 1)

      Utilisation d'un objet appelable :

      >>> mock = Mock(return_value=3)
      >>> def side_effect(*args, **kwargs):
      ...     return DEFAULT
      ...
      >>> mock.side_effect = side_effect
      >>> mock()
      3

      Un attribut "side_effect" peut être défini dans le constructeur.
      Voici un exemple qui ajoute un à la valeur du simulacre appelé
      et qui le renvoie :

      >>> side_effect = lambda value: value + 1
      >>> mock = Mock(side_effect=side_effect)
      >>> mock(3)
      4
      >>> mock(-8)
      -7

      Positionner "side_effect" sur "None" l'efface :

      >>> m = Mock(side_effect=KeyError, return_value=3)
      >>> m()
      Traceback (most recent call last):
       ...
      KeyError
      >>> m.side_effect = None
      >>> m()
      3

   call_args

      This is either "None" (if the mock hasn't been called), or the
      arguments that the mock was last called with. This will be in
      the form of a tuple: the first member, which can also be
      accessed through the "args" property, is any ordered arguments
      the mock was called with (or an empty tuple) and the second
      member, which can also be accessed through the "kwargs"
      property, is any keyword arguments (or an empty dictionary).

      >>> mock = Mock(return_value=None)
      >>> print(mock.call_args)
      None
      >>> mock()
      >>> mock.call_args
      call()
      >>> mock.call_args == ()
      True
      >>> mock(3, 4)
      >>> mock.call_args
      call(3, 4)
      >>> mock.call_args == ((3, 4),)
      True
      >>> mock.call_args.args
      (3, 4)
      >>> mock.call_args.kwargs
      {}
      >>> mock(3, 4, 5, key='fish', next='w00t!')
      >>> mock.call_args
      call(3, 4, 5, key='fish', next='w00t!')
      >>> mock.call_args.args
      (3, 4, 5)
      >>> mock.call_args.kwargs
      {'key': 'fish', 'next': 'w00t!'}

      L'attribut "call_args", ainsi que les éléments des listes
      "call_args_list", "method_calls" et "mock_calls" sont des objets
      "call". Ce sont des *n*-uplets, que l'on peut dépaqueter afin de
      faire des affirmations plus complexes sur chacun des arguments.
      Voir appels comme *n*-uplets.

      Modifié dans la version 3.8: Added "args" and "kwargs"
      properties.

   call_args_list

      This is a list of all the calls made to the mock object in
      sequence (so the length of the list is the number of times it
      has been called). Before any calls have been made it is an empty
      list. The "call" object can be used for conveniently
      constructing lists of calls to compare with "call_args_list".

      >>> mock = Mock(return_value=None)
      >>> mock()
      >>> mock(3, 4)
      >>> mock(key='fish', next='w00t!')
      >>> mock.call_args_list
      [call(), call(3, 4), call(key='fish', next='w00t!')]
      >>> expected = [(), ((3, 4),), ({'key': 'fish', 'next': 'w00t!'},)]
      >>> mock.call_args_list == expected
      True

      Members of "call_args_list" are "call" objects. These can be
      unpacked as tuples to get at the individual arguments. See calls
      as tuples.

   method_calls

      As well as tracking calls to themselves, mocks also track calls
      to methods and attributes, and *their* methods and attributes:

      >>> mock = Mock()
      >>> mock.method()
      <Mock name='mock.method()' id='...'>
      >>> mock.property.method.attribute()
      <Mock name='mock.property.method.attribute()' id='...'>
      >>> mock.method_calls
      [call.method(), call.property.method.attribute()]

      Members of "method_calls" are "call" objects. These can be
      unpacked as tuples to get at the individual arguments. See calls
      as tuples.

   mock_calls

      "mock_calls" records *all* calls to the mock object, its
      methods, magic methods *and* return value mocks.

      >>> mock = MagicMock()
      >>> result = mock(1, 2, 3)
      >>> mock.first(a=3)
      <MagicMock name='mock.first()' id='...'>
      >>> mock.second()
      <MagicMock name='mock.second()' id='...'>
      >>> int(mock)
      1
      >>> result(1)
      <MagicMock name='mock()()' id='...'>
      >>> expected = [call(1, 2, 3), call.first(a=3), call.second(),
      ... call.__int__(), call()(1)]
      >>> mock.mock_calls == expected
      True

      Members of "mock_calls" are "call" objects. These can be
      unpacked as tuples to get at the individual arguments. See calls
      as tuples.

      Note:

        The way "mock_calls" are recorded means that where nested
        calls are made, the parameters of ancestor calls are not
        recorded and so will always compare equal:

        >>> mock = MagicMock()
        >>> mock.top(a=3).bottom()
        <MagicMock name='mock.top().bottom()' id='...'>
        >>> mock.mock_calls
        [call.top(a=3), call.top().bottom()]
        >>> mock.mock_calls[-1] == call.top(a=-1).bottom()
        True

   __class__

      Normally the "__class__" attribute of an object will return its
      type. For a mock object with a "spec", "__class__" returns the
      spec class instead. This allows mock objects to pass
      "isinstance()" tests for the object they are replacing /
      masquerading as:

      >>> mock = Mock(spec=3)
      >>> isinstance(mock, int)
      True

      "__class__" is assignable to, this allows a mock to pass an
      "isinstance()" check without forcing you to use a spec:

      >>> mock = Mock()
      >>> mock.__class__ = dict
      >>> isinstance(mock, dict)
      True

class unittest.mock.NonCallableMock(spec=None, wraps=None, name=None, spec_set=None, **kwargs)

   A non-callable version of "Mock". The constructor parameters have
   the same meaning of "Mock", with the exception of *return_value*
   and *side_effect* which have no meaning on a non-callable mock.

Mock objects that use a class or an instance as a "spec" or "spec_set"
are able to pass "isinstance()" tests:

>>> mock = Mock(spec=SomeClass)
>>> isinstance(mock, SomeClass)
True
>>> mock = Mock(spec_set=SomeClass())
>>> isinstance(mock, SomeClass)
True

The "Mock" classes have support for mocking magic methods. See magic
methods for the full details.

The mock classes and the "patch()" decorators all take arbitrary
keyword arguments for configuration. For the "patch()" decorators the
keywords are passed to the constructor of the mock being created. The
keyword arguments are for configuring attributes of the mock:

>>> m = MagicMock(attribute=3, other='fish')
>>> m.attribute
3
>>> m.other
'fish'

The return value and side effect of child mocks can be set in the same
way, using dotted notation. As you can't use dotted names directly in
a call you have to create a dictionary and unpack it using "**":

>>> attrs = {'method.return_value': 3, 'other.side_effect': KeyError}
>>> mock = Mock(some_attribute='eggs', **attrs)
>>> mock.some_attribute
'eggs'
>>> mock.method()
3
>>> mock.other()
Traceback (most recent call last):
  ...
KeyError

A callable mock which was created with a *spec* (or a *spec_set*) will
introspect the specification object's signature when matching calls to
the mock.  Therefore, it can match the actual call's arguments
regardless of whether they were passed positionally or by name:

   >>> def f(a, b, c): pass
   ...
   >>> mock = Mock(spec=f)
   >>> mock(1, 2, c=3)
   <Mock name='mock()' id='140161580456576'>
   >>> mock.assert_called_with(1, 2, 3)
   >>> mock.assert_called_with(a=1, b=2, c=3)

This applies to "assert_called_with()", "assert_called_once_with()",
"assert_has_calls()" and "assert_any_call()".  When Autospeccing, it
will also apply to method calls on the mock object.

Modifié dans la version 3.4: Added signature introspection on specced
and autospecced mock objects.

class unittest.mock.PropertyMock(*args, **kwargs)

   A mock intended to be used as a "property", or other *descriptor*,
   on a class. "PropertyMock" provides "__get__()" and "__set__()"
   methods so you can specify a return value when it is fetched.

   Fetching a "PropertyMock" instance from an object calls the mock,
   with no args. Setting it calls the mock with the value being set.

      >>> class Foo:
      ...     @property
      ...     def foo(self):
      ...         return 'something'
      ...     @foo.setter
      ...     def foo(self, value):
      ...         pass
      ...
      >>> with patch('__main__.Foo.foo', new_callable=PropertyMock) as mock_foo:
      ...     mock_foo.return_value = 'mockity-mock'
      ...     this_foo = Foo()
      ...     print(this_foo.foo)
      ...     this_foo.foo = 6
      ...
      mockity-mock
      >>> mock_foo.mock_calls
      [call(), call(6)]

Because of the way mock attributes are stored you can't directly
attach a "PropertyMock" to a mock object. Instead you can attach it to
the mock type object:

   >>> m = MagicMock()
   >>> p = PropertyMock(return_value=3)
   >>> type(m).foo = p
   >>> m.foo
   3
   >>> p.assert_called_once_with()

Prudence:

  If an "AttributeError" is raised by "PropertyMock", it will be
  interpreted as a missing descriptor and "__getattr__()" will be
  called on the parent mock:

     >>> m = MagicMock()
     >>> no_attribute = PropertyMock(side_effect=AttributeError)
     >>> type(m).my_property = no_attribute
     >>> m.my_property
     <MagicMock name='mock.my_property' id='140165240345424'>

  See "__getattr__()" for details.

class unittest.mock.AsyncMock(spec=None, side_effect=None, return_value=DEFAULT, wraps=None, name=None, spec_set=None, unsafe=False, **kwargs)

   An asynchronous version of "MagicMock". The "AsyncMock" object will
   behave so the object is recognized as an async function, and the
   result of a call is an awaitable.

   >>> mock = AsyncMock()
   >>> inspect.iscoroutinefunction(mock)
   True
   >>> inspect.isawaitable(mock())  
   True

   The result of "mock()" is an async function which will have the
   outcome of "side_effect" or "return_value" after it has been
   awaited:

   * if "side_effect" is a function, the async function will return
     the result of that function,

   * if "side_effect" is an exception, the async function will raise
     the exception,

   * if "side_effect" is an iterable, the async function will return
     the next value of the iterable, however, if the sequence of
     result is exhausted, "StopAsyncIteration" is raised immediately,

   * if "side_effect" is not defined, the async function will return
     the value defined by "return_value", hence, by default, the async
     function returns a new "AsyncMock" object.

   Setting the *spec* of a "Mock" or "MagicMock" to an async function
   will result in a coroutine object being returned after calling.

   >>> async def async_func(): pass
   ...
   >>> mock = MagicMock(async_func)
   >>> mock
   <MagicMock spec='function' id='...'>
   >>> mock()  
   <coroutine object AsyncMockMixin._mock_call at ...>

   Setting the *spec* of a "Mock", "MagicMock", or "AsyncMock" to a
   class with asynchronous and synchronous functions will
   automatically detect the synchronous functions and set them as
   "MagicMock" (if the parent mock is "AsyncMock" or "MagicMock") or
   "Mock" (if the parent mock is "Mock"). All asynchronous functions
   will be "AsyncMock".

   >>> class ExampleClass:
   ...     def sync_foo():
   ...         pass
   ...     async def async_foo():
   ...         pass
   ...
   >>> a_mock = AsyncMock(ExampleClass)
   >>> a_mock.sync_foo
   <MagicMock name='mock.sync_foo' id='...'>
   >>> a_mock.async_foo
   <AsyncMock name='mock.async_foo' id='...'>
   >>> mock = Mock(ExampleClass)
   >>> mock.sync_foo
   <Mock name='mock.sync_foo' id='...'>
   >>> mock.async_foo
   <AsyncMock name='mock.async_foo' id='...'>

   Ajouté dans la version 3.8.

   assert_awaited()

      Assert that the mock was awaited at least once. Note that this
      is separate from the object having been called, the "await"
      keyword must be used:

      >>> mock = AsyncMock()
      >>> async def main(coroutine_mock):
      ...     await coroutine_mock
      ...
      >>> coroutine_mock = mock()
      >>> mock.called
      True
      >>> mock.assert_awaited()
      Traceback (most recent call last):
      ...
      AssertionError: Expected mock to have been awaited.
      >>> asyncio.run(main(coroutine_mock))
      >>> mock.assert_awaited()

   assert_awaited_once()

      Assert that the mock was awaited exactly once.

      >>> mock = AsyncMock()
      >>> async def main():
      ...     await mock()
      ...
      >>> asyncio.run(main())
      >>> mock.assert_awaited_once()
      >>> asyncio.run(main())
      >>> mock.assert_awaited_once()
      Traceback (most recent call last):
      ...
      AssertionError: Expected mock to have been awaited once. Awaited 2 times.

   assert_awaited_with(*args, **kwargs)

      Assert that the last await was with the specified arguments.

      >>> mock = AsyncMock()
      >>> async def main(*args, **kwargs):
      ...     await mock(*args, **kwargs)
      ...
      >>> asyncio.run(main('foo', bar='bar'))
      >>> mock.assert_awaited_with('foo', bar='bar')
      >>> mock.assert_awaited_with('other')
      Traceback (most recent call last):
      ...
      AssertionError: expected await not found.
      Expected: mock('other')
      Actual: mock('foo', bar='bar')

   assert_awaited_once_with(*args, **kwargs)

      Assert that the mock was awaited exactly once and with the
      specified arguments.

      >>> mock = AsyncMock()
      >>> async def main(*args, **kwargs):
      ...     await mock(*args, **kwargs)
      ...
      >>> asyncio.run(main('foo', bar='bar'))
      >>> mock.assert_awaited_once_with('foo', bar='bar')
      >>> asyncio.run(main('foo', bar='bar'))
      >>> mock.assert_awaited_once_with('foo', bar='bar')
      Traceback (most recent call last):
      ...
      AssertionError: Expected mock to have been awaited once. Awaited 2 times.

   assert_any_await(*args, **kwargs)

      Assert the mock has ever been awaited with the specified
      arguments.

      >>> mock = AsyncMock()
      >>> async def main(*args, **kwargs):
      ...     await mock(*args, **kwargs)
      ...
      >>> asyncio.run(main('foo', bar='bar'))
      >>> asyncio.run(main('hello'))
      >>> mock.assert_any_await('foo', bar='bar')
      >>> mock.assert_any_await('other')
      Traceback (most recent call last):
      ...
      AssertionError: mock('other') await not found

   assert_has_awaits(calls, any_order=False)

      Assert the mock has been awaited with the specified calls. The
      "await_args_list" list is checked for the awaits.

      If *any_order* is false then the awaits must be sequential.
      There can be extra calls before or after the specified awaits.

      If *any_order* is true then the awaits can be in any order, but
      they must all appear in "await_args_list".

      >>> mock = AsyncMock()
      >>> async def main(*args, **kwargs):
      ...     await mock(*args, **kwargs)
      ...
      >>> calls = [call("foo"), call("bar")]
      >>> mock.assert_has_awaits(calls)
      Traceback (most recent call last):
      ...
      AssertionError: Awaits not found.
      Expected: [call('foo'), call('bar')]
      Actual: []
      >>> asyncio.run(main('foo'))
      >>> asyncio.run(main('bar'))
      >>> mock.assert_has_awaits(calls)

   assert_not_awaited()

      Assert that the mock was never awaited.

      >>> mock = AsyncMock()
      >>> mock.assert_not_awaited()

   reset_mock(*args, **kwargs)

      See "Mock.reset_mock()". Also sets "await_count" to 0,
      "await_args" to None, and clears the "await_args_list".

   await_count

      An integer keeping track of how many times the mock object has
      been awaited.

      >>> mock = AsyncMock()
      >>> async def main():
      ...     await mock()
      ...
      >>> asyncio.run(main())
      >>> mock.await_count
      1
      >>> asyncio.run(main())
      >>> mock.await_count
      2

   await_args

      This is either "None" (if the mock hasn’t been awaited), or the
      arguments that the mock was last awaited with. Functions the
      same as "Mock.call_args".

      >>> mock = AsyncMock()
      >>> async def main(*args):
      ...     await mock(*args)
      ...
      >>> mock.await_args
      >>> asyncio.run(main('foo'))
      >>> mock.await_args
      call('foo')
      >>> asyncio.run(main('bar'))
      >>> mock.await_args
      call('bar')

   await_args_list

      This is a list of all the awaits made to the mock object in
      sequence (so the length of the list is the number of times it
      has been awaited). Before any awaits have been made it is an
      empty list.

      >>> mock = AsyncMock()
      >>> async def main(*args):
      ...     await mock(*args)
      ...
      >>> mock.await_args_list
      []
      >>> asyncio.run(main('foo'))
      >>> mock.await_args_list
      [call('foo')]
      >>> asyncio.run(main('bar'))
      >>> mock.await_args_list
      [call('foo'), call('bar')]

class unittest.mock.ThreadingMock(spec=None, side_effect=None, return_value=DEFAULT, wraps=None, name=None, spec_set=None, unsafe=False, *, timeout=UNSET, **kwargs)

   A version of "MagicMock" for multithreading tests. The
   "ThreadingMock" object provides extra methods to wait for a call to
   be invoked, rather than assert on it immediately.

   The default timeout is specified by the "timeout" argument, or if
   unset by the "ThreadingMock.DEFAULT_TIMEOUT" attribute, which
   defaults to blocking ("None").

   You can configure the global default timeout by setting
   "ThreadingMock.DEFAULT_TIMEOUT".

   wait_until_called(*, timeout=UNSET)

      Waits until the mock is called.

      If a timeout was passed at the creation of the mock or if a
      timeout argument is passed to this function, the function raises
      an "AssertionError" if the call is not performed in time.

      >>> mock = ThreadingMock()
      >>> thread = threading.Thread(target=mock)
      >>> thread.start()
      >>> mock.wait_until_called(timeout=1)
      >>> thread.join()

   wait_until_any_call_with(*args, **kwargs)

      Waits until the mock is called with the specified arguments.

      If a timeout was passed at the creation of the mock the function
      raises an "AssertionError" if the call is not performed in time.

      >>> mock = ThreadingMock()
      >>> thread = threading.Thread(target=mock, args=("arg1", "arg2",), kwargs={"arg": "thing"})
      >>> thread.start()
      >>> mock.wait_until_any_call_with("arg1", "arg2", arg="thing")
      >>> thread.join()

   DEFAULT_TIMEOUT

      Global default timeout in seconds to create instances of
      "ThreadingMock".

   Ajouté dans la version 3.13.


Calling
-------

Mock objects are callable. The call will return the value set as the
"return_value" attribute. The default return value is a new Mock
object; it is created the first time the return value is accessed
(either explicitly or by calling the Mock) - but it is stored and the
same one returned each time.

Calls made to the object will be recorded in the attributes like
"call_args" and "call_args_list".

If "side_effect" is set then it will be called after the call has been
recorded, so if "side_effect" raises an exception the call is still
recorded.

The simplest way to make a mock raise an exception when called is to
make "side_effect" an exception class or instance:

>>> m = MagicMock(side_effect=IndexError)
>>> m(1, 2, 3)
Traceback (most recent call last):
  ...
IndexError
>>> m.mock_calls
[call(1, 2, 3)]
>>> m.side_effect = KeyError('Bang!')
>>> m('two', 'three', 'four')
Traceback (most recent call last):
  ...
KeyError: 'Bang!'
>>> m.mock_calls
[call(1, 2, 3), call('two', 'three', 'four')]

If "side_effect" is a function then whatever that function returns is
what calls to the mock return. The "side_effect" function is called
with the same arguments as the mock. This allows you to vary the
return value of the call dynamically, based on the input:

>>> def side_effect(value):
...     return value + 1
...
>>> m = MagicMock(side_effect=side_effect)
>>> m(1)
2
>>> m(2)
3
>>> m.mock_calls
[call(1), call(2)]

If you want the mock to still return the default return value (a new
mock), or any set return value, then there are two ways of doing this.
Either return "return_value" from inside "side_effect", or return
"DEFAULT":

>>> m = MagicMock()
>>> def side_effect(*args, **kwargs):
...     return m.return_value
...
>>> m.side_effect = side_effect
>>> m.return_value = 3
>>> m()
3
>>> def side_effect(*args, **kwargs):
...     return DEFAULT
...
>>> m.side_effect = side_effect
>>> m()
3

To remove a "side_effect", and return to the default behaviour, set
the "side_effect" to "None":

>>> m = MagicMock(return_value=6)
>>> def side_effect(*args, **kwargs):
...     return 3
...
>>> m.side_effect = side_effect
>>> m()
3
>>> m.side_effect = None
>>> m()
6

The "side_effect" can also be any iterable object. Repeated calls to
the mock will return values from the iterable (until the iterable is
exhausted and a "StopIteration" is raised):

>>> m = MagicMock(side_effect=[1, 2, 3])
>>> m()
1
>>> m()
2
>>> m()
3
>>> m()
Traceback (most recent call last):
  ...
StopIteration

If any members of the iterable are exceptions they will be raised
instead of returned:

   >>> iterable = (33, ValueError, 66)
   >>> m = MagicMock(side_effect=iterable)
   >>> m()
   33
   >>> m()
   Traceback (most recent call last):
    ...
   ValueError
   >>> m()
   66


Deleting Attributes
-------------------

Mock objects create attributes on demand. This allows them to pretend
to be objects of any type.

You may want a mock object to return "False" to a "hasattr()" call, or
raise an "AttributeError" when an attribute is fetched. You can do
this by providing an object as a "spec" for a mock, but that isn't
always convenient.

You "block" attributes by deleting them. Once deleted, accessing an
attribute will raise an "AttributeError".

>>> mock = MagicMock()
>>> hasattr(mock, 'm')
True
>>> del mock.m
>>> hasattr(mock, 'm')
False
>>> del mock.f
>>> mock.f
Traceback (most recent call last):
    ...
AttributeError: f


Mock names and the name attribute
---------------------------------

Since "name" is an argument to the "Mock" constructor, if you want
your mock object to have a "name" attribute you can't just pass it in
at creation time. There are two alternatives. One option is to use
"configure_mock()":

   >>> mock = MagicMock()
   >>> mock.configure_mock(name='my_name')
   >>> mock.name
   'my_name'

A simpler option is to simply set the "name" attribute after mock
creation:

   >>> mock = MagicMock()
   >>> mock.name = "foo"


Attaching Mocks as Attributes
-----------------------------

When you attach a mock as an attribute of another mock (or as the
return value) it becomes a "child" of that mock. Calls to the child
are recorded in the "method_calls" and "mock_calls" attributes of the
parent. This is useful for configuring child mocks and then attaching
them to the parent, or for attaching mocks to a parent that records
all calls to the children and allows you to make assertions about the
order of calls between mocks:

>>> parent = MagicMock()
>>> child1 = MagicMock(return_value=None)
>>> child2 = MagicMock(return_value=None)
>>> parent.child1 = child1
>>> parent.child2 = child2
>>> child1(1)
>>> child2(2)
>>> parent.mock_calls
[call.child1(1), call.child2(2)]

The exception to this is if the mock has a name. This allows you to
prevent the "parenting" if for some reason you don't want it to
happen.

>>> mock = MagicMock()
>>> not_a_child = MagicMock(name='not-a-child')
>>> mock.attribute = not_a_child
>>> mock.attribute()
<MagicMock name='not-a-child()' id='...'>
>>> mock.mock_calls
[]

Mocks created for you by "patch()" are automatically given names. To
attach mocks that have names to a parent you use the "attach_mock()"
method:

   >>> thing1 = object()
   >>> thing2 = object()
   >>> parent = MagicMock()
   >>> with patch('__main__.thing1', return_value=None) as child1:
   ...     with patch('__main__.thing2', return_value=None) as child2:
   ...         parent.attach_mock(child1, 'child1')
   ...         parent.attach_mock(child2, 'child2')
   ...         child1('one')
   ...         child2('two')
   ...
   >>> parent.mock_calls
   [call.child1('one'), call.child2('two')]

[1] The only exceptions are magic methods and attributes (those that
    have leading and trailing double underscores). Mock doesn't create
    these but instead raises an "AttributeError". This is because the
    interpreter will often implicitly request these methods, and gets
    *very* confused to get a new Mock object when it expects a magic
    method. If you need magic method support see magic methods.


The patchers
============

The patch decorators are used for patching objects only within the
scope of the function they decorate. They automatically handle the
unpatching for you, even if exceptions are raised. All of these
functions can also be used in with statements or as class decorators.


patch
-----

Note:

  The key is to do the patching in the right namespace. See the
  section where to patch.

unittest.mock.patch(target, new=DEFAULT, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)

   "patch()" acts as a function decorator, class decorator or a
   context manager. Inside the body of the function or with statement,
   the *target* is patched with a *new* object. When the function/with
   statement exits the patch is undone.

   If *new* is omitted, then the target is replaced with an
   "AsyncMock" if the patched object is an async function or a
   "MagicMock" otherwise. If "patch()" is used as a decorator and
   *new* is omitted, the created mock is passed in as an extra
   argument to the decorated function. If "patch()" is used as a
   context manager the created mock is returned by the context
   manager.

   *target* should be a string in the form
   "'package.module.ClassName'". The *target* is imported and the
   specified object replaced with the *new* object, so the *target*
   must be importable from the environment you are calling "patch()"
   from. The target is imported when the decorated function is
   executed, not at decoration time.

   The *spec* and *spec_set* keyword arguments are passed to the
   "MagicMock" if patch is creating one for you.

   In addition you can pass "spec=True" or "spec_set=True", which
   causes patch to pass in the object being mocked as the
   spec/spec_set object.

   *new_callable* allows you to specify a different class, or callable
   object, that will be called to create the *new* object. By default
   "AsyncMock" is used for async functions and "MagicMock" for the
   rest.

   A more powerful form of *spec* is *autospec*. If you set
   "autospec=True" then the mock will be created with a spec from the
   object being replaced. All attributes of the mock will also have
   the spec of the corresponding attribute of the object being
   replaced. Methods and functions being mocked will have their
   arguments checked and will raise a "TypeError" if they are called
   with the wrong signature. For mocks replacing a class, their return
   value (the 'instance') will have the same spec as the class. See
   the "create_autospec()" function and Autospeccing.

   Instead of "autospec=True" you can pass "autospec=some_object" to
   use an arbitrary object as the spec instead of the one being
   replaced.

   By default "patch()" will fail to replace attributes that don't
   exist. If you pass in "create=True", and the attribute doesn't
   exist, patch will create the attribute for you when the patched
   function is called, and delete it again after the patched function
   has exited. This is useful for writing tests against attributes
   that your production code creates at runtime. It is off by default
   because it can be dangerous. With it switched on you can write
   passing tests against APIs that don't actually exist!

   Note:

     Modifié dans la version 3.5: If you are patching builtins in a
     module then you don't need to pass "create=True", it will be
     added by default.

   Patch can be used as a "TestCase" class decorator. It works by
   decorating each test method in the class. This reduces the
   boilerplate code when your test methods share a common patchings
   set. "patch()" finds tests by looking for method names that start
   with "patch.TEST_PREFIX". By default this is "'test'", which
   matches the way "unittest" finds tests. You can specify an
   alternative prefix by setting "patch.TEST_PREFIX".

   Patch can be used as a context manager, with the with statement.
   Here the patching applies to the indented block after the with
   statement. If you use "as" then the patched object will be bound to
   the name after the "as"; very useful if "patch()" is creating a
   mock object for you.

   "patch()" takes arbitrary keyword arguments. These will be passed
   to "AsyncMock" if the patched object is asynchronous, to
   "MagicMock" otherwise or to *new_callable* if specified.

   "patch.dict(...)", "patch.multiple(...)" and "patch.object(...)"
   are available for alternate use-cases.

"patch()" as function decorator, creating the mock for you and passing
it into the decorated function:

   >>> @patch('__main__.SomeClass')
   ... def function(normal_argument, mock_class):
   ...     print(mock_class is SomeClass)
   ...
   >>> function(None)
   True

Patching a class replaces the class with a "MagicMock" *instance*. If
the class is instantiated in the code under test then it will be the
"return_value" of the mock that will be used.

If the class is instantiated multiple times you could use
"side_effect" to return a new mock each time. Alternatively you can
set the *return_value* to be anything you want.

To configure return values on methods of *instances* on the patched
class you must do this on the "return_value". For example:

   >>> class Class:
   ...     def method(self):
   ...         pass
   ...
   >>> with patch('__main__.Class') as MockClass:
   ...     instance = MockClass.return_value
   ...     instance.method.return_value = 'foo'
   ...     assert Class() is instance
   ...     assert Class().method() == 'foo'
   ...

If you use *spec* or *spec_set* and "patch()" is replacing a *class*,
then the return value of the created mock will have the same spec.

   >>> Original = Class
   >>> patcher = patch('__main__.Class', spec=True)
   >>> MockClass = patcher.start()
   >>> instance = MockClass()
   >>> assert isinstance(instance, Original)
   >>> patcher.stop()

The *new_callable* argument is useful where you want to use an
alternative class to the default "MagicMock" for the created mock. For
example, if you wanted a "NonCallableMock" to be used:

   >>> thing = object()
   >>> with patch('__main__.thing', new_callable=NonCallableMock) as mock_thing:
   ...     assert thing is mock_thing
   ...     thing()
   ...
   Traceback (most recent call last):
     ...
   TypeError: 'NonCallableMock' object is not callable

Another use case might be to replace an object with an "io.StringIO"
instance:

   >>> from io import StringIO
   >>> def foo():
   ...     print('Something')
   ...
   >>> @patch('sys.stdout', new_callable=StringIO)
   ... def test(mock_stdout):
   ...     foo()
   ...     assert mock_stdout.getvalue() == 'Something\n'
   ...
   >>> test()

When "patch()" is creating a mock for you, it is common that the first
thing you need to do is to configure the mock. Some of that
configuration can be done in the call to patch. Any arbitrary keywords
you pass into the call will be used to set attributes on the created
mock:

   >>> patcher = patch('__main__.thing', first='one', second='two')
   >>> mock_thing = patcher.start()
   >>> mock_thing.first
   'one'
   >>> mock_thing.second
   'two'

As well as attributes on the created mock attributes, like the
"return_value" and "side_effect", of child mocks can also be
configured. These aren't syntactically valid to pass in directly as
keyword arguments, but a dictionary with these as keys can still be
expanded into a "patch()" call using "**":

   >>> config = {'method.return_value': 3, 'other.side_effect': KeyError}
   >>> patcher = patch('__main__.thing', **config)
   >>> mock_thing = patcher.start()
   >>> mock_thing.method()
   3
   >>> mock_thing.other()
   Traceback (most recent call last):
     ...
   KeyError

By default, attempting to patch a function in a module (or a method or
an attribute in a class) that does not exist will fail with
"AttributeError":

   >>> @patch('sys.non_existing_attribute', 42)
   ... def test():
   ...     assert sys.non_existing_attribute == 42
   ...
   >>> test()
   Traceback (most recent call last):
     ...
   AttributeError: <module 'sys' (built-in)> does not have the attribute 'non_existing_attribute'

but adding "create=True" in the call to "patch()" will make the
previous example work as expected:

   >>> @patch('sys.non_existing_attribute', 42, create=True)
   ... def test(mock_stdout):
   ...     assert sys.non_existing_attribute == 42
   ...
   >>> test()

Modifié dans la version 3.8: "patch()" now returns an "AsyncMock" if
the target is an async function.


patch.object
------------

patch.object(target, attribute, new=DEFAULT, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)

   patch the named member (*attribute*) on an object (*target*) with a
   mock object.

   "patch.object()" can be used as a decorator, class decorator or a
   context manager. Arguments *new*, *spec*, *create*, *spec_set*,
   *autospec* and *new_callable* have the same meaning as for
   "patch()". Like "patch()", "patch.object()" takes arbitrary keyword
   arguments for configuring the mock object it creates.

   When used as a class decorator "patch.object()" honours
   "patch.TEST_PREFIX" for choosing which methods to wrap.

You can either call "patch.object()" with three arguments or two
arguments. The three argument form takes the object to be patched, the
attribute name and the object to replace the attribute with.

When calling with the two argument form you omit the replacement
object, and a mock is created for you and passed in as an extra
argument to the decorated function:

>>> @patch.object(SomeClass, 'class_method')
... def test(mock_method):
...     SomeClass.class_method(3)
...     mock_method.assert_called_with(3)
...
>>> test()

*spec*, *create* and the other arguments to "patch.object()" have the
same meaning as they do for "patch()".


patch.dict
----------

patch.dict(in_dict, values=(), clear=False, **kwargs)

   Patch a dictionary, or dictionary like object, and restore the
   dictionary to its original state after the test, where the restored
   dictionary is a copy of the dictionary as it was before the test.

   *in_dict* can be a dictionary or a mapping like container. If it is
   a mapping then it must at least support getting, setting and
   deleting items plus iterating over keys.

   *in_dict* can also be a string specifying the name of the
   dictionary, which will then be fetched by importing it.

   *values* can be a dictionary of values to set in the dictionary.
   *values* can also be an iterable of "(key, value)" pairs.

   If *clear* is true then the dictionary will be cleared before the
   new values are set.

   "patch.dict()" can also be called with arbitrary keyword arguments
   to set values in the dictionary.

   Modifié dans la version 3.8: "patch.dict()" now returns the patched
   dictionary when used as a context manager.

"patch.dict()" can be used as a context manager, decorator or class
decorator:

>>> foo = {}
>>> @patch.dict(foo, {'newkey': 'newvalue'})
... def test():
...     assert foo == {'newkey': 'newvalue'}
...
>>> test()
>>> assert foo == {}

When used as a class decorator "patch.dict()" honours
"patch.TEST_PREFIX" (default to "'test'") for choosing which methods
to wrap:

>>> import os
>>> import unittest
>>> from unittest.mock import patch
>>> @patch.dict('os.environ', {'newkey': 'newvalue'})
... class TestSample(unittest.TestCase):
...     def test_sample(self):
...         self.assertEqual(os.environ['newkey'], 'newvalue')

If you want to use a different prefix for your test, you can inform
the patchers of the different prefix by setting "patch.TEST_PREFIX".
For more details about how to change the value of see TEST_PREFIX.

"patch.dict()" can be used to add members to a dictionary, or simply
let a test change a dictionary, and ensure the dictionary is restored
when the test ends.

>>> foo = {}
>>> with patch.dict(foo, {'newkey': 'newvalue'}) as patched_foo:
...     assert foo == {'newkey': 'newvalue'}
...     assert patched_foo == {'newkey': 'newvalue'}
...     # You can add, update or delete keys of foo (or patched_foo, it's the same dict)
...     patched_foo['spam'] = 'eggs'
...
>>> assert foo == {}
>>> assert patched_foo == {}

>>> import os
>>> with patch.dict('os.environ', {'newkey': 'newvalue'}):
...     print(os.environ['newkey'])
...
newvalue
>>> assert 'newkey' not in os.environ

Keywords can be used in the "patch.dict()" call to set values in the
dictionary:

>>> mymodule = MagicMock()
>>> mymodule.function.return_value = 'fish'
>>> with patch.dict('sys.modules', mymodule=mymodule):
...     import mymodule
...     mymodule.function('some', 'args')
...
'fish'

"patch.dict()" can be used with dictionary like objects that aren't
actually dictionaries. At the very minimum they must support item
getting, setting, deleting and either iteration or membership test.
This corresponds to the magic methods "__getitem__()",
"__setitem__()", "__delitem__()" and either "__iter__()" or
"__contains__()".

>>> class Container:
...     def __init__(self):
...         self.values = {}
...     def __getitem__(self, name):
...         return self.values[name]
...     def __setitem__(self, name, value):
...         self.values[name] = value
...     def __delitem__(self, name):
...         del self.values[name]
...     def __iter__(self):
...         return iter(self.values)
...
>>> thing = Container()
>>> thing['one'] = 1
>>> with patch.dict(thing, one=2, two=3):
...     assert thing['one'] == 2
...     assert thing['two'] == 3
...
>>> assert thing['one'] == 1
>>> assert list(thing) == ['one']


patch.multiple
--------------

patch.multiple(target, spec=None, create=False, spec_set=None, autospec=None, new_callable=None, **kwargs)

   Perform multiple patches in a single call. It takes the object to
   be patched (either as an object or a string to fetch the object by
   importing) and keyword arguments for the patches:

      with patch.multiple(settings, FIRST_PATCH='one', SECOND_PATCH='two'):
          ...

   Use "DEFAULT" as the value if you want "patch.multiple()" to create
   mocks for you. In this case the created mocks are passed into a
   decorated function by keyword, and a dictionary is returned when
   "patch.multiple()" is used as a context manager.

   "patch.multiple()" can be used as a decorator, class decorator or a
   context manager. The arguments *spec*, *spec_set*, *create*,
   *autospec* and *new_callable* have the same meaning as for
   "patch()". These arguments will be applied to *all* patches done by
   "patch.multiple()".

   When used as a class decorator "patch.multiple()" honours
   "patch.TEST_PREFIX" for choosing which methods to wrap.

If you want "patch.multiple()" to create mocks for you, then you can
use "DEFAULT" as the value. If you use "patch.multiple()" as a
decorator then the created mocks are passed into the decorated
function by keyword.

   >>> thing = object()
   >>> other = object()

   >>> @patch.multiple('__main__', thing=DEFAULT, other=DEFAULT)
   ... def test_function(thing, other):
   ...     assert isinstance(thing, MagicMock)
   ...     assert isinstance(other, MagicMock)
   ...
   >>> test_function()

"patch.multiple()" can be nested with other "patch" decorators, but
put arguments passed by keyword *after* any of the standard arguments
created by "patch()":

   >>> @patch('sys.exit')
   ... @patch.multiple('__main__', thing=DEFAULT, other=DEFAULT)
   ... def test_function(mock_exit, other, thing):
   ...     assert 'other' in repr(other)
   ...     assert 'thing' in repr(thing)
   ...     assert 'exit' in repr(mock_exit)
   ...
   >>> test_function()

If "patch.multiple()" is used as a context manager, the value returned
by the context manager is a dictionary where created mocks are keyed
by name:

   >>> with patch.multiple('__main__', thing=DEFAULT, other=DEFAULT) as values:
   ...     assert 'other' in repr(values['other'])
   ...     assert 'thing' in repr(values['thing'])
   ...     assert values['thing'] is thing
   ...     assert values['other'] is other
   ...


patch methods: start and stop
-----------------------------

All the patchers have "start()" and "stop()" methods. These make it
simpler to do patching in "setUp" methods or where you want to do
multiple patches without nesting decorators or with statements.

To use them call "patch()", "patch.object()" or "patch.dict()" as
normal and keep a reference to the returned "patcher" object. You can
then call "start()" to put the patch in place and "stop()" to undo it.

If you are using "patch()" to create a mock for you then it will be
returned by the call to "patcher.start".

   >>> patcher = patch('package.module.ClassName')
   >>> from package import module
   >>> original = module.ClassName
   >>> new_mock = patcher.start()
   >>> assert module.ClassName is not original
   >>> assert module.ClassName is new_mock
   >>> patcher.stop()
   >>> assert module.ClassName is original
   >>> assert module.ClassName is not new_mock

A typical use case for this might be for doing multiple patches in the
"setUp" method of a "TestCase":

   >>> class MyTest(unittest.TestCase):
   ...     def setUp(self):
   ...         self.patcher1 = patch('package.module.Class1')
   ...         self.patcher2 = patch('package.module.Class2')
   ...         self.MockClass1 = self.patcher1.start()
   ...         self.MockClass2 = self.patcher2.start()
   ...
   ...     def tearDown(self):
   ...         self.patcher1.stop()
   ...         self.patcher2.stop()
   ...
   ...     def test_something(self):
   ...         assert package.module.Class1 is self.MockClass1
   ...         assert package.module.Class2 is self.MockClass2
   ...
   >>> MyTest('test_something').run()

Prudence:

  If you use this technique you must ensure that the patching is
  "undone" by calling "stop". This can be fiddlier than you might
  think, because if an exception is raised in the "setUp" then
  "tearDown" is not called. "unittest.TestCase.addCleanup()" makes
  this easier:

     >>> class MyTest(unittest.TestCase):
     ...     def setUp(self):
     ...         patcher = patch('package.module.Class')
     ...         self.MockClass = patcher.start()
     ...         self.addCleanup(patcher.stop)
     ...
     ...     def test_something(self):
     ...         assert package.module.Class is self.MockClass
     ...

  As an added bonus you no longer need to keep a reference to the
  "patcher" object.

It is also possible to stop all patches which have been started by
using "patch.stopall()".

patch.stopall()

   Stop all active patches. Only stops patches started with "start".


patch builtins
--------------

You can patch any builtins within a module. The following example
patches builtin "ord()":

   >>> @patch('__main__.ord')
   ... def test(mock_ord):
   ...     mock_ord.return_value = 101
   ...     print(ord('c'))
   ...
   >>> test()
   101


TEST_PREFIX
-----------

All of the patchers can be used as class decorators. When used in this
way they wrap every test method on the class. The patchers recognise
methods that start with "'test'" as being test methods. This is the
same way that the "unittest.TestLoader" finds test methods by default.

It is possible that you want to use a different prefix for your tests.
You can inform the patchers of the different prefix by setting
"patch.TEST_PREFIX":

   >>> patch.TEST_PREFIX = 'foo'
   >>> value = 3
   >>>
   >>> @patch('__main__.value', 'not three')
   ... class Thing:
   ...     def foo_one(self):
   ...         print(value)
   ...     def foo_two(self):
   ...         print(value)
   ...
   >>>
   >>> Thing().foo_one()
   not three
   >>> Thing().foo_two()
   not three
   >>> value
   3


Nesting Patch Decorators
------------------------

If you want to perform multiple patches then you can simply stack up
the decorators.

You can stack up multiple patch decorators using this pattern:

>>> @patch.object(SomeClass, 'class_method')
... @patch.object(SomeClass, 'static_method')
... def test(mock1, mock2):
...     assert SomeClass.static_method is mock1
...     assert SomeClass.class_method is mock2
...     SomeClass.static_method('foo')
...     SomeClass.class_method('bar')
...     return mock1, mock2
...
>>> mock1, mock2 = test()
>>> mock1.assert_called_once_with('foo')
>>> mock2.assert_called_once_with('bar')

Note that the decorators are applied from the bottom upwards. This is
the standard way that Python applies decorators. The order of the
created mocks passed into your test function matches this order.


Where to patch
--------------

"patch()" works by (temporarily) changing the object that a *name*
points to with another one. There can be many names pointing to any
individual object, so for patching to work you must ensure that you
patch the name used by the system under test.

The basic principle is that you patch where an object is *looked up*,
which is not necessarily the same place as where it is defined. A
couple of examples will help to clarify this.

Imagine we have a project that we want to test with the following
structure:

   a.py
       -> Defines SomeClass

   b.py
       -> from a import SomeClass
       -> some_function instantiates SomeClass

Now we want to test "some_function" but we want to mock out
"SomeClass" using "patch()". The problem is that when we import module
b, which we will have to do then it imports "SomeClass" from module a.
If we use "patch()" to mock out "a.SomeClass" then it will have no
effect on our test; module b already has a reference to the *real*
"SomeClass" and it looks like our patching had no effect.

The key is to patch out "SomeClass" where it is used (or where it is
looked up). In this case "some_function" will actually look up
"SomeClass" in module b, where we have imported it. The patching
should look like:

   @patch('b.SomeClass')

However, consider the alternative scenario where instead of "from a
import SomeClass" module b does "import a" and "some_function" uses
"a.SomeClass". Both of these import forms are common. In this case the
class we want to patch is being looked up in the module and so we have
to patch "a.SomeClass" instead:

   @patch('a.SomeClass')


Patching Descriptors and Proxy Objects
--------------------------------------

Both patch and patch.object correctly patch and restore descriptors:
class methods, static methods and properties. You should patch these
on the *class* rather than an instance. They also work with *some*
objects that proxy attribute access, like the django settings object.


MagicMock and magic method support
==================================


Mocking Magic Methods
---------------------

"Mock" supports mocking the Python protocol methods, also known as
*"magic methods"*. This allows mock objects to replace containers or
other objects that implement Python protocols.

Because magic methods are looked up differently from normal methods
[2], this support has been specially implemented. This means that only
specific magic methods are supported. The supported list includes
*almost* all of them. If there are any missing that you need please
let us know.

You mock magic methods by setting the method you are interested in to
a function or a mock instance. If you are using a function then it
*must* take "self" as the first argument [3].

>>> def __str__(self):
...     return 'fooble'
...
>>> mock = Mock()
>>> mock.__str__ = __str__
>>> str(mock)
'fooble'

>>> mock = Mock()
>>> mock.__str__ = Mock()
>>> mock.__str__.return_value = 'fooble'
>>> str(mock)
'fooble'

>>> mock = Mock()
>>> mock.__iter__ = Mock(return_value=iter([]))
>>> list(mock)
[]

One use case for this is for mocking objects used as context managers
in a "with" statement:

>>> mock = Mock()
>>> mock.__enter__ = Mock(return_value='foo')
>>> mock.__exit__ = Mock(return_value=False)
>>> with mock as m:
...     assert m == 'foo'
...
>>> mock.__enter__.assert_called_with()
>>> mock.__exit__.assert_called_with(None, None, None)

Calls to magic methods do not appear in "method_calls", but they are
recorded in "mock_calls".

Note:

  If you use the *spec* keyword argument to create a mock then
  attempting to set a magic method that isn't in the spec will raise
  an "AttributeError".

The full list of supported magic methods is:

* "__hash__", "__sizeof__", "__repr__" and "__str__"

* "__dir__", "__format__" et "__subclasses__"

* "__round__", "__floor__", "__trunc__" and "__ceil__"

* Comparisons: "__lt__", "__gt__", "__le__", "__ge__", "__eq__" and
  "__ne__"

* Container methods: "__getitem__", "__setitem__", "__delitem__",
  "__contains__", "__len__", "__iter__", "__reversed__" and
  "__missing__"

* Context manager: "__enter__", "__exit__", "__aenter__" and
  "__aexit__"

* Unary numeric methods: "__neg__", "__pos__" and "__invert__"

* The numeric methods (including right hand and in-place variants):
  "__add__", "__sub__", "__mul__", "__matmul__", "__truediv__",
  "__floordiv__", "__mod__", "__divmod__", "__lshift__", "__rshift__",
  "__and__", "__xor__", "__or__", and "__pow__"

* Numeric conversion methods: "__complex__", "__int__", "__float__"
  and "__index__"

* Descriptor methods: "__get__", "__set__" and "__delete__"

* Pickling: "__reduce__", "__reduce_ex__", "__getinitargs__",
  "__getnewargs__", "__getstate__" and "__setstate__"

* File system path representation: "__fspath__"

* Asynchronous iteration methods: "__aiter__" and "__anext__"

Modifié dans la version 3.8: Added support for
"os.PathLike.__fspath__()".

Modifié dans la version 3.8: Added support for "__aenter__",
"__aexit__", "__aiter__" and "__anext__".

The following methods exist but are *not* supported as they are either
in use by mock, can't be set dynamically, or can cause problems:

* "__getattr__", "__setattr__", "__init__" and "__new__"

* "__prepare__", "__instancecheck__", "__subclasscheck__", "__del__"


Magic Mock
----------

There are two "MagicMock" variants: "MagicMock" and
"NonCallableMagicMock".

class unittest.mock.MagicMock(*args, **kw)

   "MagicMock" is a subclass of "Mock" with default implementations of
   most of the *magic methods*. You can use "MagicMock" without having
   to configure the magic methods yourself.

   The constructor parameters have the same meaning as for "Mock".

   If you use the *spec* or *spec_set* arguments then *only* magic
   methods that exist in the spec will be created.

class unittest.mock.NonCallableMagicMock(*args, **kw)

   A non-callable version of "MagicMock".

   The constructor parameters have the same meaning as for
   "MagicMock", with the exception of *return_value* and *side_effect*
   which have no meaning on a non-callable mock.

The magic methods are setup with "MagicMock" objects, so you can
configure them and use them in the usual way:

>>> mock = MagicMock()
>>> mock[3] = 'fish'
>>> mock.__setitem__.assert_called_with(3, 'fish')
>>> mock.__getitem__.return_value = 'result'
>>> mock[2]
'result'

By default many of the protocol methods are required to return objects
of a specific type. These methods are preconfigured with a default
return value, so that they can be used without you having to do
anything if you aren't interested in the return value. You can still
*set* the return value manually if you want to change the default.

Methods and their defaults:

* "__lt__": "NotImplemented"

* "__gt__": "NotImplemented"

* "__le__": "NotImplemented"

* "__ge__": "NotImplemented"

* "__int__": "1"

* "__contains__": "False"

* "__int__": "0"

* "__iter__": "iter([])"

* "__exit__": "False"

* "__exit__": "False"

* "__complex__": "1j"

* "__float__": "1.0"

* "__bool__": "True"

* "__index__": "1"

* "__hash__": default hash for the mock

* "__str__": default str for the mock

* "__sizeof__": default sizeof for the mock

Par exemple :

>>> mock = MagicMock()
>>> int(mock)
1
>>> len(mock)
0
>>> list(mock)
[]
>>> object() in mock
False

The two equality methods, "__eq__()" and "__ne__()", are special. They
do the default equality comparison on identity, using the
"side_effect" attribute, unless you change their return value to
return something else:

   >>> MagicMock() == 3
   False
   >>> MagicMock() != 3
   True
   >>> mock = MagicMock()
   >>> mock.__eq__.return_value = True
   >>> mock == 3
   True

The return value of "MagicMock.__iter__()" can be any iterable object
and isn't required to be an iterator:

>>> mock = MagicMock()
>>> mock.__iter__.return_value = ['a', 'b', 'c']
>>> list(mock)
['a', 'b', 'c']
>>> list(mock)
['a', 'b', 'c']

If the return value *is* an iterator, then iterating over it once will
consume it and subsequent iterations will result in an empty list:

>>> mock.__iter__.return_value = iter(['a', 'b', 'c'])
>>> list(mock)
['a', 'b', 'c']
>>> list(mock)
[]

"MagicMock" has all of the supported magic methods configured except
for some of the obscure and obsolete ones. You can still set these up
if you want.

Magic methods that are supported but not setup by default in
"MagicMock" are:

* "__subclasses__"

* "__dir__"

* "__format__"

* "__get__", "__set__" et "__delete__"

* "__reversed__" et "__missing__"

* "__reduce__", "__reduce_ex__", "__getinitargs__", "__getnewargs__",
  "__getstate__" and "__setstate__"

* "__getformat__"

[2] Magic methods *should* be looked up on the class rather than the
    instance. Different versions of Python are inconsistent about
    applying this rule. The supported protocol methods should work
    with all supported versions of Python.

[3] The function is basically hooked up to the class, but each "Mock"
    instance is kept isolated from the others.


Helpers
=======


sentinel
--------

unittest.mock.sentinel

   The "sentinel" object provides a convenient way of providing unique
   objects for your tests.

   Attributes are created on demand when you access them by name.
   Accessing the same attribute will always return the same object.
   The objects returned have a sensible repr so that test failure
   messages are readable.

   Modifié dans la version 3.7: The "sentinel" attributes now preserve
   their identity when they are "copied" or "pickled".

Sometimes when testing you need to test that a specific object is
passed as an argument to another method, or returned. It can be common
to create named sentinel objects to test this. "sentinel" provides a
convenient way of creating and testing the identity of objects like
this.

In this example we monkey patch "method" to return
"sentinel.some_object":

>>> real = ProductionClass()
>>> real.method = Mock(name="method")
>>> real.method.return_value = sentinel.some_object
>>> result = real.method()
>>> assert result is sentinel.some_object
>>> result
sentinel.some_object


DEFAULT
-------

unittest.mock.DEFAULT

   The "DEFAULT" object is a pre-created sentinel (actually
   "sentinel.DEFAULT"). It can be used by "side_effect" functions to
   indicate that the normal return value should be used.


appel
-----

unittest.mock.call(*args, **kwargs)

   "call()" is a helper object for making simpler assertions, for
   comparing with "call_args", "call_args_list", "mock_calls" and
   "method_calls". "call()" can also be used with
   "assert_has_calls()".

   >>> m = MagicMock(return_value=None)
   >>> m(1, 2, a='foo', b='bar')
   >>> m()
   >>> m.call_args_list == [call(1, 2, a='foo', b='bar'), call()]
   True

call.call_list()

   For a call object that represents multiple calls, "call_list()"
   returns a list of all the intermediate calls as well as the final
   call.

"call_list" is particularly useful for making assertions on "chained
calls". A chained call is multiple calls on a single line of code.
This results in multiple entries in "mock_calls" on a mock. Manually
constructing the sequence of calls can be tedious.

"call_list()" can construct the sequence of calls from the same
chained call:

>>> m = MagicMock()
>>> m(1).method(arg='foo').other('bar')(2.0)
<MagicMock name='mock().method().other()()' id='...'>
>>> kall = call(1).method(arg='foo').other('bar')(2.0)
>>> kall.call_list()
[call(1),
 call().method(arg='foo'),
 call().method().other('bar'),
 call().method().other()(2.0)]
>>> m.mock_calls == kall.call_list()
True

A "call" object is either a tuple of (positional args, keyword args)
or (name, positional args, keyword args) depending on how it was
constructed. When you construct them yourself this isn't particularly
interesting, but the "call" objects that are in the "Mock.call_args",
"Mock.call_args_list" and "Mock.mock_calls" attributes can be
introspected to get at the individual arguments they contain.

The "call" objects in "Mock.call_args" and "Mock.call_args_list" are
two-tuples of (positional args, keyword args) whereas the "call"
objects in "Mock.mock_calls", along with ones you construct yourself,
are three-tuples of (name, positional args, keyword args).

You can use their "tupleness" to pull out the individual arguments for
more complex introspection and assertions. The positional arguments
are a tuple (an empty tuple if there are no positional arguments) and
the keyword arguments are a dictionary:

>>> m = MagicMock(return_value=None)
>>> m(1, 2, 3, arg='one', arg2='two')
>>> kall = m.call_args
>>> kall.args
(1, 2, 3)
>>> kall.kwargs
{'arg': 'one', 'arg2': 'two'}
>>> kall.args is kall[0]
True
>>> kall.kwargs is kall[1]
True

>>> m = MagicMock()
>>> m.foo(4, 5, 6, arg='two', arg2='three')
<MagicMock name='mock.foo()' id='...'>
>>> kall = m.mock_calls[0]
>>> name, args, kwargs = kall
>>> name
'foo'
>>> args
(4, 5, 6)
>>> kwargs
{'arg': 'two', 'arg2': 'three'}
>>> name is m.mock_calls[0][0]
True


create_autospec
---------------

unittest.mock.create_autospec(spec, spec_set=False, instance=False, **kwargs)

   Create a mock object using another object as a spec. Attributes on
   the mock will use the corresponding attribute on the *spec* object
   as their spec.

   Functions or methods being mocked will have their arguments checked
   to ensure that they are called with the correct signature.

   If *spec_set* is "True" then attempting to set attributes that
   don't exist on the spec object will raise an "AttributeError".

   If a class is used as a spec then the return value of the mock (the
   instance of the class) will have the same spec. You can use a class
   as the spec for an instance object by passing "instance=True". The
   returned mock will only be callable if instances of the mock are
   callable.

   "create_autospec()" also takes arbitrary keyword arguments that are
   passed to the constructor of the created mock.

See Autospeccing for examples of how to use auto-speccing with
"create_autospec()" and the *autospec* argument to "patch()".

Modifié dans la version 3.8: "create_autospec()" now returns an
"AsyncMock" if the target is an async function.


ANY
---

unittest.mock.ANY

Sometimes you may need to make assertions about *some* of the
arguments in a call to mock, but either not care about some of the
arguments or want to pull them individually out of "call_args" and
make more complex assertions on them.

To ignore certain arguments you can pass in objects that compare equal
to *everything*. Calls to "assert_called_with()" and
"assert_called_once_with()" will then succeed no matter what was
passed in.

>>> mock = Mock(return_value=None)
>>> mock('foo', bar=object())
>>> mock.assert_called_once_with('foo', bar=ANY)

"ANY" can also be used in comparisons with call lists like
"mock_calls":

>>> m = MagicMock(return_value=None)
>>> m(1)
>>> m(1, 2)
>>> m(object())
>>> m.mock_calls == [call(1), call(1, 2), ANY]
True

"ANY" is not limited to comparisons with call objects and so can also
be used in test assertions:

   class TestStringMethods(unittest.TestCase):

       def test_split(self):
           s = 'hello world'
           self.assertEqual(s.split(), ['hello', ANY])


FILTER_DIR
----------

unittest.mock.FILTER_DIR

"FILTER_DIR" is a module level variable that controls the way mock
objects respond to "dir()". The default is "True", which uses the
filtering described below, to only show useful members. If you dislike
this filtering, or need to switch it off for diagnostic purposes, then
set "mock.FILTER_DIR = False".

With filtering on, "dir(some_mock)" shows only useful attributes and
will include any dynamically created attributes that wouldn't normally
be shown. If the mock was created with a *spec* (or *autospec* of
course) then all the attributes from the original are shown, even if
they haven't been accessed yet:

   >>> dir(Mock())
   ['assert_any_call',
    'assert_called',
    'assert_called_once',
    'assert_called_once_with',
    'assert_called_with',
    'assert_has_calls',
    'assert_not_called',
    'attach_mock',
    ...
   >>> from urllib import request
   >>> dir(Mock(spec=request))
   ['AbstractBasicAuthHandler',
    'AbstractDigestAuthHandler',
    'AbstractHTTPHandler',
    'BaseHandler',
    ...

Many of the not-very-useful (private to "Mock" rather than the thing
being mocked) underscore and double underscore prefixed attributes
have been filtered from the result of calling "dir()" on a "Mock". If
you dislike this behaviour you can switch it off by setting the module
level switch "FILTER_DIR":

   >>> from unittest import mock
   >>> mock.FILTER_DIR = False
   >>> dir(mock.Mock())
   ['_NonCallableMock__get_return_value',
    '_NonCallableMock__get_side_effect',
    '_NonCallableMock__return_value_doc',
    '_NonCallableMock__set_return_value',
    '_NonCallableMock__set_side_effect',
    '__call__',
    '__class__',
    ...

Alternatively you can just use "vars(my_mock)" (instance members) and
"dir(type(my_mock))" (type members) to bypass the filtering
irrespective of "FILTER_DIR".


mock_open
---------

unittest.mock.mock_open(mock=None, read_data=None)

   A helper function to create a mock to replace the use of "open()".
   It works for "open()" called directly or used as a context manager.

   The *mock* argument is the mock object to configure. If "None" (the
   default) then a "MagicMock" will be created for you, with the API
   limited to methods or attributes available on standard file
   handles.

   *read_data* is a string for the "read()", "readline()", and
   "readlines()" methods of the file handle to return.  Calls to those
   methods will take data from *read_data* until it is depleted.  The
   mock of these methods is pretty simplistic: every time the *mock*
   is called, the *read_data* is rewound to the start.  If you need
   more control over the data that you are feeding to the tested code
   you will need to customize this mock for yourself.  When that is
   insufficient, one of the in-memory filesystem packages on PyPI can
   offer a realistic filesystem for testing.

   Modifié dans la version 3.4: Added "readline()" and "readlines()"
   support. The mock of "read()" changed to consume *read_data* rather
   than returning it on each call.

   Modifié dans la version 3.5: *read_data* is now reset on each call
   to the *mock*.

   Modifié dans la version 3.8: Added "__iter__()" to implementation
   so that iteration (such as in for loops) correctly consumes
   *read_data*.

Using "open()" as a context manager is a great way to ensure your file
handles are closed properly and is becoming common:

   with open('/some/path', 'w') as f:
       f.write('something')

The issue is that even if you mock out the call to "open()" it is the
*returned object* that is used as a context manager (and has
"__enter__()" and "__exit__()" called).

Mocking context managers with a "MagicMock" is common enough and
fiddly enough that a helper function is useful.

   >>> m = mock_open()
   >>> with patch('__main__.open', m):
   ...     with open('foo', 'w') as h:
   ...         h.write('some stuff')
   ...
   >>> m.mock_calls
   [call('foo', 'w'),
    call().__enter__(),
    call().write('some stuff'),
    call().__exit__(None, None, None)]
   >>> m.assert_called_once_with('foo', 'w')
   >>> handle = m()
   >>> handle.write.assert_called_once_with('some stuff')

And for reading files:

   >>> with patch('__main__.open', mock_open(read_data='bibble')) as m:
   ...     with open('foo') as h:
   ...         result = h.read()
   ...
   >>> m.assert_called_once_with('foo')
   >>> assert result == 'bibble'


Autospeccing
------------

Autospeccing is based on the existing "spec" feature of mock. It
limits the api of mocks to the api of an original object (the spec),
but it is recursive (implemented lazily) so that attributes of mocks
only have the same api as the attributes of the spec. In addition
mocked functions / methods have the same call signature as the
original so they raise a "TypeError" if they are called incorrectly.

Before I explain how auto-speccing works, here's why it is needed.

"Mock" is a very powerful and flexible object, but it suffers from a
flaw which is general to mocking. If you refactor some of your code,
rename members and so on, any tests for code that is still using the
*old api* but uses mocks instead of the real objects will still pass.
This means your tests can all pass even though your code is broken.

Modifié dans la version 3.5: Before 3.5, tests with a typo in the word
assert would silently pass when they should raise an error. You can
still achieve this behavior by passing "unsafe=True" to Mock.

Note that this is another reason why you need integration tests as
well as unit tests. Testing everything in isolation is all fine and
dandy, but if you don't test how your units are "wired together" there
is still lots of room for bugs that tests might have caught.

"unittest.mock" already provides a feature to help with this, called
speccing. If you use a class or instance as the "spec" for a mock then
you can only access attributes on the mock that exist on the real
class:

>>> from urllib import request
>>> mock = Mock(spec=request.Request)
>>> mock.assret_called_with  # Intentional typo!
Traceback (most recent call last):
 ...
AttributeError: Mock object has no attribute 'assret_called_with'

The spec only applies to the mock itself, so we still have the same
issue with any methods on the mock:

   >>> mock.has_data()
   <mock.Mock object at 0x...>
   >>> mock.has_data.assret_called_with()  # Intentional typo!

Auto-speccing solves this problem. You can either pass "autospec=True"
to "patch()" / "patch.object()" or use the "create_autospec()"
function to create a mock with a spec. If you use the "autospec=True"
argument to "patch()" then the object that is being replaced will be
used as the spec object. Because the speccing is done "lazily" (the
spec is created as attributes on the mock are accessed) you can use it
with very complex or deeply nested objects (like modules that import
modules that import modules) without a big performance hit.

Here's an example of it in use:

   >>> from urllib import request
   >>> patcher = patch('__main__.request', autospec=True)
   >>> mock_request = patcher.start()
   >>> request is mock_request
   True
   >>> mock_request.Request
   <MagicMock name='request.Request' spec='Request' id='...'>

You can see that "request.Request" has a spec. "request.Request" takes
two arguments in the constructor (one of which is *self*). Here's what
happens if we try to call it incorrectly:

   >>> req = request.Request()
   Traceback (most recent call last):
    ...
   TypeError: <lambda>() takes at least 2 arguments (1 given)

The spec also applies to instantiated classes (i.e. the return value
of specced mocks):

   >>> req = request.Request('foo')
   >>> req
   <NonCallableMagicMock name='request.Request()' spec='Request' id='...'>

"Request" objects are not callable, so the return value of
instantiating our mocked out "request.Request" is a non-callable mock.
With the spec in place any typos in our asserts will raise the correct
error:

   >>> req.add_header('spam', 'eggs')
   <MagicMock name='request.Request().add_header()' id='...'>
   >>> req.add_header.assret_called_with  # Intentional typo!
   Traceback (most recent call last):
    ...
   AttributeError: Mock object has no attribute 'assret_called_with'
   >>> req.add_header.assert_called_with('spam', 'eggs')

In many cases you will just be able to add "autospec=True" to your
existing "patch()" calls and then be protected against bugs due to
typos and api changes.

As well as using *autospec* through "patch()" there is a
"create_autospec()" for creating autospecced mocks directly:

>>> from urllib import request
>>> mock_request = create_autospec(request)
>>> mock_request.Request('foo', 'bar')
<NonCallableMagicMock name='mock.Request()' spec='Request' id='...'>

This isn't without caveats and limitations however, which is why it is
not the default behaviour. In order to know what attributes are
available on the spec object, autospec has to introspect (access
attributes) the spec. As you traverse attributes on the mock a
corresponding traversal of the original object is happening under the
hood. If any of your specced objects have properties or descriptors
that can trigger code execution then you may not be able to use
autospec. On the other hand it is much better to design your objects
so that introspection is safe [4].

A more serious problem is that it is common for instance attributes to
be created in the "__init__()" method and not to exist on the class at
all. *autospec* can't know about any dynamically created attributes
and restricts the api to visible attributes.

   >>> class Something:
   ...   def __init__(self):
   ...     self.a = 33
   ...
   >>> with patch('__main__.Something', autospec=True):
   ...   thing = Something()
   ...   thing.a
   ...
   Traceback (most recent call last):
     ...
   AttributeError: Mock object has no attribute 'a'

There are a few different ways of resolving this problem. The easiest,
but not necessarily the least annoying, way is to simply set the
required attributes on the mock after creation. Just because
*autospec* doesn't allow you to fetch attributes that don't exist on
the spec it doesn't prevent you setting them:

   >>> with patch('__main__.Something', autospec=True):
   ...   thing = Something()
   ...   thing.a = 33
   ...

There is a more aggressive version of both *spec* and *autospec* that
*does* prevent you setting non-existent attributes. This is useful if
you want to ensure your code only *sets* valid attributes too, but
obviously it prevents this particular scenario:

>>> with patch('__main__.Something', autospec=True, spec_set=True):
...   thing = Something()
...   thing.a = 33
...
Traceback (most recent call last):
 ...
AttributeError: Mock object has no attribute 'a'

Probably the best way of solving the problem is to add class
attributes as default values for instance members initialised in
"__init__()". Note that if you are only setting default attributes in
"__init__()" then providing them via class attributes (shared between
instances of course) is faster too. e.g.

   class Something:
       a = 33

This brings up another issue. It is relatively common to provide a
default value of "None" for members that will later be an object of a
different type. "None" would be useless as a spec because it wouldn't
let you access *any* attributes or methods on it. As "None" is *never*
going to be useful as a spec, and probably indicates a member that
will normally of some other type, autospec doesn't use a spec for
members that are set to "None". These will just be ordinary mocks
(well - MagicMocks):

>>> class Something:
...     member = None
...
>>> mock = create_autospec(Something)
>>> mock.member.foo.bar.baz()
<MagicMock name='mock.member.foo.bar.baz()' id='...'>

If modifying your production classes to add defaults isn't to your
liking then there are more options. One of these is simply to use an
instance as the spec rather than the class. The other is to create a
subclass of the production class and add the defaults to the subclass
without affecting the production class. Both of these require you to
use an alternative object as the spec. Thankfully "patch()" supports
this - you can simply pass the alternative object as the *autospec*
argument:

   >>> class Something:
   ...   def __init__(self):
   ...     self.a = 33
   ...
   >>> class SomethingForTest(Something):
   ...   a = 33
   ...
   >>> p = patch('__main__.Something', autospec=SomethingForTest)
   >>> mock = p.start()
   >>> mock.a
   <NonCallableMagicMock name='Something.a' spec='int' id='...'>

[4] This only applies to classes or already instantiated objects.
    Calling a mocked class to create a mock instance *does not* create
    a real instance. It is only attribute lookups - along with calls
    to "dir()" - that are done.


Sealing mocks
-------------

unittest.mock.seal(mock)

   Seal will disable the automatic creation of mocks when accessing an
   attribute of the mock being sealed or any of its attributes that
   are already mocks recursively.

   If a mock instance with a name or a spec is assigned to an
   attribute it won't be considered in the sealing chain. This allows
   one to prevent seal from fixing part of the mock object.

      >>> mock = Mock()
      >>> mock.submock.attribute1 = 2
      >>> mock.not_submock = mock.Mock(name="sample_name")
      >>> seal(mock)
      >>> mock.new_attribute  # This will raise AttributeError.
      >>> mock.submock.attribute2  # This will raise AttributeError.
      >>> mock.not_submock.attribute2  # This won't raise.

   Ajouté dans la version 3.7.


Order of precedence of "side_effect", "return_value" and *wraps*
================================================================

The order of their precedence is:

1. "side_effect"

2. "return_value"

3. *wraps*

If all three are set, mock will return the value from "side_effect",
ignoring "return_value" and the wrapped object altogether. If any two
are set, the one with the higher precedence will return the value.
Regardless of the order of which was set first, the order of
precedence remains unchanged.

>>> from unittest.mock import Mock
>>> class Order:
...     @staticmethod
...     def get_value():
...         return "third"
...
>>> order_mock = Mock(spec=Order, wraps=Order)
>>> order_mock.get_value.side_effect = ["first"]
>>> order_mock.get_value.return_value = "second"
>>> order_mock.get_value()
'first'

As "None" is the default value of "side_effect", if you reassign its
value back to "None", the order of precedence will be checked between
"return_value" and the wrapped object, ignoring "side_effect".

>>> order_mock.get_value.side_effect = None
>>> order_mock.get_value()
'second'

If the value being returned by "side_effect" is "DEFAULT", it is
ignored and the order of precedence moves to the successor to obtain
the value to return.

>>> from unittest.mock import DEFAULT
>>> order_mock.get_value.side_effect = [DEFAULT]
>>> order_mock.get_value()
'second'

When "Mock" wraps an object, the default value of "return_value" will
be "DEFAULT".

>>> order_mock = Mock(spec=Order, wraps=Order)
>>> order_mock.return_value
sentinel.DEFAULT
>>> order_mock.get_value.return_value
sentinel.DEFAULT

The order of precedence will ignore this value and it will move to the
last successor which is the wrapped object.

As the real call is being made to the wrapped object, creating an
instance of this mock will return the real instance of the class. The
positional arguments, if any, required by the wrapped object must be
passed.

>>> order_mock_instance = order_mock()
>>> isinstance(order_mock_instance, Order)
True
>>> order_mock_instance.get_value()
'third'

>>> order_mock.get_value.return_value = DEFAULT
>>> order_mock.get_value()
'third'

>>> order_mock.get_value.return_value = "second"
>>> order_mock.get_value()
'second'

But if you assign "None" to it, this will not be ignored as it is an
explicit assignment. So, the order of precedence will not move to the
wrapped object.

>>> order_mock.get_value.return_value = None
>>> order_mock.get_value() is None
True

Even if you set all three at once when initializing the mock, the
order of precedence remains the same:

>>> order_mock = Mock(spec=Order, wraps=Order,
...                   **{"get_value.side_effect": ["first"],
...                      "get_value.return_value": "second"}
...                   )
...
>>> order_mock.get_value()
'first'
>>> order_mock.get_value.side_effect = None
>>> order_mock.get_value()
'second'
>>> order_mock.get_value.return_value = DEFAULT
>>> order_mock.get_value()
'third'

If "side_effect" is exhausted, the order of precedence will not cause
a value to be obtained from the successors. Instead, "StopIteration"
exception is raised.

>>> order_mock = Mock(spec=Order, wraps=Order)
>>> order_mock.get_value.side_effect = ["first side effect value",
...                                     "another side effect value"]
>>> order_mock.get_value.return_value = "second"

>>> order_mock.get_value()
'first side effect value'
>>> order_mock.get_value()
'another side effect value'

>>> order_mock.get_value()
Traceback (most recent call last):
 ...
StopIteration
