Testing tools

Testing tools

Django provides a small set of tools that come in handy when writing tests.

The test client

The test client is a Python class that acts as a dummy web browser, allowing you to test your views and interact with your Django-powered application programmatically.

Some of the things you can do with the test client are:

  • Simulate GET and POST requests on a URL and observe the response – everything from low-level HTTP (result headers and status codes) to page content.
  • See the chain of redirects (if any) and check the URL and status code at each step.
  • Test that a given request is rendered by a given Django template, with a template context that contains certain values.

Note that the test client is not intended to be a replacement for Selenium or other “in-browser” frameworks. Django’s test client has a different focus. In short:

  • Use Django’s test client to establish that the correct template is being rendered and that the template is passed the correct context data.
  • Use RequestFactory to test view functions directly, bypassing the routing and middleware layers.
  • Use in-browser frameworks like Selenium to test rendered HTML and the behavior of web pages, namely JavaScript functionality. Django also provides special support for those frameworks; see the section on LiveServerTestCase for more details.

A comprehensive test suite should use a combination of all of these test types.

Overview and a quick example

To use the test client, instantiate django.test.Client and retrieve web pages:

>>> from django.test import Client
>>> c = Client()
>>> response = c.post("/login/", {"username": "john", "password": "smith"})
>>> response.status_code
200
>>> response = c.get("/customer/details/")
>>> response.content
b'<!DOCTYPE html...'

As this example suggests, you can instantiate Client from within a session of the Python interactive interpreter.

Note a few important things about how the test client works:

  • The test client does not require the web server to be running. In fact, it will run just fine with no web server running at all! That’s because it avoids the overhead of HTTP and deals directly with the Django framework. This helps make the unit tests run quickly.

  • When retrieving pages, remember to specify the path of the URL, not the whole domain. For example, this is correct:

>>> c.get("/login/")

This is incorrect:

>>> c.get("https://www.example.com/login/")

The test client is not capable of retrieving web pages that are not powered by your Django project. If you need to retrieve other web pages, use a Python standard library module such as urllib.

  • To resolve URLs, the test client uses whatever URLconf is pointed-to by your ROOT_URLCONF setting.

  • Although the above example would work in the Python interactive interpreter, some of the test client’s functionality, notably the template-related functionality, is only available while tests are running.

The reason for this is that Django’s test runner performs a bit of black magic in order to determine which template was loaded by a given view. This black magic (essentially a patching of Django’s template system in memory) only happens during test running.

  • By default, the test client will disable any CSRF checks performed by your site.

If, for some reason, you want the test client to perform CSRF checks, you can create an instance of the test client that enforces CSRF checks. To do this, pass in the enforce_csrf_checks argument when you construct your client:

>>> from django.test import Client
>>> csrf_client = Client(enforce_csrf_checks=True)

Making requests

Use the django.test.Client class to make requests.

class Client(enforce_csrf_checks=False , raise_request_exception=True , json_encoder=DjangoJSONEncoder , , _headers=None , query_params=None , _*defaults)[source]

A testing HTTP client. Takes several arguments that can customize behavior.

headers allows you to specify default headers that will be sent with every request. For example, to set a User-Agent header:

client = Client(headers={"user-agent": "curl/7.79.1"})

query_params allows you to specify the default query string that will be set on every request.

Arbitrary keyword arguments in **defaults set WSGI environ variables. For example, to set the script name:

client = Client(SCRIPT_NAME="/app/")

Note

Keyword arguments starting with a HTTP_ prefix are set as headers, but the headers parameter should be preferred for readability.

The values from the headers, query_params, and extra keyword arguments passed to get(), post(), etc. have precedence over the defaults passed to the class constructor.

The enforce_csrf_checks argument can be used to test CSRF protection (see above).

The raise_request_exception argument allows controlling whether or not exceptions raised during the request should also be raised in the test. Defaults to True.

The json_encoder argument allows setting a custom JSON encoder for the JSON serialization that’s described in post().

Changed in Django 5.1:

The query_params argument was added.

Once you have a Client instance, you can call any of the following methods:

  • get(path , data=None , follow=False , secure=False , , _headers=None , query_params=None , _*extra)[source]

Makes a GET request on the provided path and returns a Response object, which is documented below.

The key-value pairs in the query_params dictionary are used to set query strings. For example:

>>> c = Client()
>>> c.get("/customers/details/", query_params={"name": "fred", "age": 7})

…will result in the evaluation of a GET request equivalent to:

/customers/details/?name=fred&age=7

It is also possible to pass these parameters into the data parameter. However, query_params is preferred as it works for any HTTP method.

The headers parameter can be used to specify headers to be sent in the request. For example:

>>> c = Client()
>>> c.get(
...     "/customers/details/",
...     query_params={"name": "fred", "age": 7},
...     headers={"accept": "application/json"},
... )

…will send the HTTP header HTTP_ACCEPT to the details view, which is a good way to test code paths that use the django.http.HttpRequest.accepts() method.

Arbitrary keyword arguments set WSGI environ variables. For example, headers to set the script name:

>>> c = Client()
>>> c.get("/", SCRIPT_NAME="/app/")

If you already have the GET arguments in URL-encoded form, you can use that encoding instead of using the data argument. For example, the previous GET request could also be posed as:

>>> c = Client()
>>> c.get("/customers/details/?name=fred&age=7")

If you provide a URL with both an encoded GET data and either a query_params or data argument these arguments will take precedence.

If you set follow to True the client will follow any redirects and a redirect_chain attribute will be set in the response object containing tuples of the intermediate urls and status codes.

If you had a URL /redirect_me/ that redirected to /next/, that redirected to /final/, this is what you’d see:

>>> response = c.get("/redirect_me/", follow=True)
>>> response.redirect_chain
[('http://testserver/next/', 302), ('http://testserver/final/', 302)]

If you set secure to True the client will emulate an HTTPS request.

Changed in Django 5.1:

The query_params argument was added.

  • post(path , data=None , content_type=MULTIPART_CONTENT , follow=False , secure=False , , _headers=None , query_params=None , _*extra)[source]

Makes a POST request on the provided path and returns a Response object, which is documented below.

The key-value pairs in the data dictionary are used to submit POST data. For example:

>>> c = Client()
>>> c.post("/login/", {"name": "fred", "passwd": "secret"})

…will result in the evaluation of a POST request to this URL:

/login/

…with this POST data:

name=fred&passwd=secret

If you provide content_type as application/json , the data is serialized using json.dumps() if it’s a dict, list, or tuple. Serialization is performed with DjangoJSONEncoder by default, and can be overridden by providing a json_encoder argument to Client. This serialization also happens for put(), patch(), and delete() requests.

If you provide any other content_type (e.g. text/xml for an XML payload), the contents of data are sent as-is in the POST request, using content_type in the HTTP Content-Type header.

If you don’t provide a value for content_type, the values in data will be transmitted with a content type of multipart/form-data. In this case, the key-value pairs in data will be encoded as a multipart message and used to create the POST data payload.

To submit multiple values for a given key – for example, to specify the selections for a <select multiple> – provide the values as a list or tuple for the required key. For example, this value of data would submit three selected values for the field named choices:

{"choices": ["a", "b", "d"]}

Submitting files is a special case. To POST a file, you need only provide the file field name as a key, and a file handle to the file you wish to upload as a value. For example, if your form has fields name and attachment, the latter a FileField:

>>> c = Client()
>>> with open("wishlist.doc", "rb") as fp:
...     c.post("/customers/wishes/", {"name": "fred", "attachment": fp})
...

You may also provide any file-like object (e.g., StringIO or BytesIO) as a file handle. If you’re uploading to an ImageField, the object needs a name attribute that passes the validate_image_file_extension validator. For example:

>>> from io import BytesIO
>>> img = BytesIO(
...     b"GIF89a\x01\x00\x01\x00\x00\x00\x00!\xf9\x04\x01\x00\x00\x00"
...     b"\x00,\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x01\x00\x00"
... )
>>> img.name = "myimage.gif"

Note that if you wish to use the same file handle for multiple post() calls then you will need to manually reset the file pointer between posts. The easiest way to do this is to manually close the file after it has been provided to post(), as demonstrated above.

You should also ensure that the file is opened in a way that allows the data to be read. If your file contains binary data such as an image, this means you will need to open the file in rb (read binary) mode.

The headers, query_params, and extra parameters acts the same as for Client.get().

If the URL you request with a POST contains encoded parameters, these parameters will be made available in the request.GET data. For example, if you were to make the request:

>>> c.post(
...     "/login/", {"name": "fred", "passwd": "secret"}, query_params={"visitor": "true"}
... )

… the view handling this request could interrogate request.POST to retrieve the username and password, and could interrogate request.GET to determine if the user was a visitor.

If you set follow to True the client will follow any redirects and a redirect_chain attribute will be set in the response object containing tuples of the intermediate urls and status codes.

If you set secure to True the client will emulate an HTTPS request.

Changed in Django 5.1:

The query_params argument was added.

  • head(path , data=None , follow=False , secure=False , , _headers=None , query_params=None , _*extra)[source]

Makes a HEAD request on the provided path and returns a Response object. This method works just like Client.get(), including the follow, secure, headers, query_params, and extra parameters, except it does not return a message body.

Changed in Django 5.1:

The query_params argument was added.

  • options(path , data=’’ , content_type=’application/octet-stream’ , follow=False , secure=False , , _headers=None , query_params=None , _*extra)[source]

Makes an OPTIONS request on the provided path and returns a Response object. Useful for testing RESTful interfaces.

When data is provided, it is used as the request body, and a Content-Type header is set to content_type.

The follow, secure, headers, query_params, and extra parameters act the same as for Client.get().

Changed in Django 5.1:

The query_params argument was added.

  • put(path , data=’’ , content_type=’application/octet-stream’ , follow=False , secure=False , , _headers=None , query_params=None , _*extra)[source]

Makes a PUT request on the provided path and returns a Response object. Useful for testing RESTful interfaces.

When data is provided, it is used as the request body, and a Content-Type header is set to content_type.

The follow, secure, headers, query_params, and extra parameters act the same as for Client.get().

Changed in Django 5.1:

The query_params argument was added.

  • patch(path , data=’’ , content_type=’application/octet-stream’ , follow=False , secure=False , , _headers=None , query_params=None , _*extra)[source]

Makes a PATCH request on the provided path and returns a Response object. Useful for testing RESTful interfaces.

The follow, secure, headers, query_params, and extra parameters act the same as for Client.get().

Changed in Django 5.1:

The query_params argument was added.

  • delete(path , data=’’ , content_type=’application/octet-stream’ , follow=False , secure=False , , _headers=None , query_params=None , _*extra)[source]

Makes a DELETE request on the provided path and returns a Response object. Useful for testing RESTful interfaces.

When data is provided, it is used as the request body, and a Content-Type header is set to content_type.

The follow, secure, headers, query_params, and extra parameters act the same as for Client.get().

Changed in Django 5.1:

The query_params argument was added.

  • trace(path , follow=False , secure=False , , _headers=None , query_params=None , _*extra)[source]

Makes a TRACE request on the provided path and returns a Response object. Useful for simulating diagnostic probes.

Unlike the other request methods, data is not provided as a keyword parameter in order to comply with RFC 9110#section-9.3.8, which mandates that TRACE requests must not have a body.

The follow, secure, headers, query_params, and extra parameters act the same as for Client.get().

Changed in Django 5.1:

The query_params argument was added.

  • login(**credentials)

  • alogin(**credentials)

Asynchronous version : alogin()

If your site uses Django’s authentication system and you deal with logging in users, you can use the test client’s login() method to simulate the effect of a user logging into the site.

After you call this method, the test client will have all the cookies and session data required to pass any login-based tests that may form part of a view.

The format of the credentials argument depends on which authentication backend you’re using (which is configured by your AUTHENTICATION_BACKENDS setting). If you’re using the standard authentication backend provided by Django (ModelBackend), credentials should be the user’s username and password, provided as keyword arguments:

>>> c = Client()
>>> c.login(username="fred", password="secret")

## Now you can access a view that's only available to logged-in users.

If you’re using a different authentication backend, this method may require different credentials. It requires whichever credentials are required by your backend’s authenticate() method.

login() returns True if it the credentials were accepted and login was successful.

Finally, you’ll need to remember to create user accounts before you can use this method. As we explained above, the test runner is executed using a test database, which contains no users by default. As a result, user accounts that are valid on your production site will not work under test conditions. You’ll need to create users as part of the test suite – either manually (using the Django model API) or with a test fixture. Remember that if you want your test user to have a password, you can’t set the user’s password by setting the password attribute directly – you must use the set_password() function to store a correctly hashed password. Alternatively, you can use the create_user() helper method to create a new user with a correctly hashed password.

Changed in Django 5.0:

alogin() method was added.

  • force_login(user , backend=None)

  • aforce_login(user , backend=None)

Asynchronous version : aforce_login()

If your site uses Django’s authentication system, you can use the force_login() method to simulate the effect of a user logging into the site. Use this method instead of login() when a test requires a user be logged in and the details of how a user logged in aren’t important.

Unlike login(), this method skips the authentication and verification steps: inactive users (is_active=False) are permitted to login and the user’s credentials don’t need to be provided.

The user will have its backend attribute set to the value of the backend argument (which should be a dotted Python path string), or to settings.AUTHENTICATION_BACKENDS[0] if a value isn’t provided. The authenticate() function called by login() normally annotates the user like this.

This method is faster than login() since the expensive password hashing algorithms are bypassed. Also, you can speed up login() by using a weaker hasher while testing.

Changed in Django 5.0:

aforce_login() method was added.

  • logout()

  • alogout()

Asynchronous version : alogout()

If your site uses Django’s authentication system, the logout() method can be used to simulate the effect of a user logging out of your site.

After you call this method, the test client will have all the cookies and session data cleared to defaults. Subsequent requests will appear to come from an AnonymousUser.

Changed in Django 5.0:

alogout() method was added.

Testing responses

The get() and post() methods both return a Response object. This Response object is not the same as the HttpResponse object returned by Django views; the test response object has some additional data useful for test code to verify.

Specifically, a Response object has the following attributes:

class Response

  • client

The test client that was used to make the request that resulted in the response.

  • content

The body of the response, as a bytestring. This is the final page content as rendered by the view, or any error message.

  • context

The template Context instance that was used to render the template that produced the response content.

If the rendered page used multiple templates, then context will be a list of Context objects, in the order in which they were rendered.

Regardless of the number of templates used during rendering, you can retrieve context values using the [] operator. For example, the context variable name could be retrieved using:

>>> response = client.get("/foo/")
>>> response.context["name"]
'Arthur'

Not using Django templates?

This attribute is only populated when using the DjangoTemplates backend. If you’re using another template engine, context_data may be a suitable alternative on responses with that attribute.

  • exc_info

A tuple of three values that provides information about the unhandled exception, if any, that occurred during the view.

The values are (type, value, traceback), the same as returned by Python’s sys.exc_info(). Their meanings are:

* _type_ : The type of the exception.
* _value_ : The exception instance.
* _traceback_ : A traceback object which encapsulates the call stack at the point where the exception originally occurred.

If no exception occurred, then exc_info will be None.

  • json(**kwargs)

The body of the response, parsed as JSON. Extra keyword arguments are passed to json.loads(). For example:

>>> response = client.get("/foo/")
>>> response.json()["name"]
'Arthur'

If the Content-Type header is not "application/json", then a ValueError will be raised when trying to parse the response.

  • request

The request data that stimulated the response.

  • wsgi_request

The WSGIRequest instance generated by the test handler that generated the response.

  • status_code

The HTTP status of the response, as an integer. For a full list of defined codes, see the IANA status code registry.

  • templates

A list of Template instances used to render the final content, in the order they were rendered. For each template in the list, use template.name to get the template’s file name, if the template was loaded from a file. (The name is a string such as 'admin/index.html'.)

Not using Django templates?

This attribute is only populated when using the DjangoTemplates backend. If you’re using another template engine, template_name may be a suitable alternative if you only need the name of the template used for rendering.

  • resolver_match

An instance of ResolverMatch for the response. You can use the func attribute, for example, to verify the view that served the response:

## my_view here is a function based view.
self.assertEqual(response.resolver_match.func, my_view)

## Class-based views need to compare the view_class, as the
## functions generated by as_view() won't be equal.
self.assertIs(response.resolver_match.func.view_class, MyView)

If the given URL is not found, accessing this attribute will raise a Resolver404 exception.

As with a normal response, you can also access the headers through HttpResponse.headers. For example, you could determine the content type of a response using response.headers['Content-Type'].

Exceptions

If you point the test client at a view that raises an exception and Client.raise_request_exception is True, that exception will be visible in the test case. You can then use a standard try ... except block or assertRaises() to test for exceptions.

The only exceptions that are not visible to the test client are Http404, PermissionDenied, SystemExit, and SuspiciousOperation. Django catches these exceptions internally and converts them into the appropriate HTTP response codes. In these cases, you can check response.status_code in your test.

If Client.raise_request_exception is False, the test client will return a 500 response as would be returned to a browser. The response has the attribute exc_info to provide information about the unhandled exception.

Persistent state

The test client is stateful. If a response returns a cookie, then that cookie will be stored in the test client and sent with all subsequent get() and post() requests.

Expiration policies for these cookies are not followed. If you want a cookie to expire, either delete it manually or create a new Client instance (which will effectively delete all cookies).

A test client has attributes that store persistent state information. You can access these properties as part of a test condition.

Client.cookies

A Python SimpleCookie object, containing the current values of all the client cookies. See the documentation of the http.cookies module for more.

Client.session

A dictionary-like object containing session information. See the session documentation for full details.

To modify the session and then save it, it must be stored in a variable first (because a new SessionStore is created every time this property is accessed):

def test_something(self):
    session = self.client.session
    session["somekey"] = "test"
    session.save()

Client.asession()

New in Django 5.0.

This is similar to the session attribute but it works in async contexts.

Setting the language

When testing applications that support internationalization and localization, you might want to set the language for a test client request. The method for doing so depends on whether or not the LocaleMiddleware is enabled.

If the middleware is enabled, the language can be set by creating a cookie with a name of LANGUAGE_COOKIE_NAME and a value of the language code:

from django.conf import settings

def test_language_using_cookie(self):
    self.client.cookies.load({settings.LANGUAGE_COOKIE_NAME: "fr"})
    response = self.client.get("/")
    self.assertEqual(response.content, b"Bienvenue sur mon site.")

or by including the Accept-Language HTTP header in the request:

def test_language_using_header(self):
    response = self.client.get("/", headers={"accept-language": "fr"})
    self.assertEqual(response.content, b"Bienvenue sur mon site.")

Note

When using these methods, ensure to reset the active language at the end of each test:

def tearDown(self):
    translation.activate(settings.LANGUAGE_CODE)

More details are in How Django discovers language preference.

If the middleware isn’t enabled, the active language may be set using translation.override():

from django.utils import translation

def test_language_using_override(self):
    with translation.override("fr"):
        response = self.client.get("/")
    self.assertEqual(response.content, b"Bienvenue sur mon site.")

More details are in Explicitly setting the active language.

Example

The following is a unit test using the test client:

import unittest
from django.test import Client

class SimpleTest(unittest.TestCase):
    def setUp(self):
        # Every test needs a client.
        self.client = Client()

    def test_details(self):
        # Issue a GET request.
        response = self.client.get("/customer/details/")

        # Check that the response is 200 OK.
        self.assertEqual(response.status_code, 200)

        # Check that the rendered context contains 5 customers.
        self.assertEqual(len(response.context["customers"]), 5)

See also

django.test.RequestFactory

Provided test case classes

Normal Python unit test classes extend a base class of unittest.TestCase. Django provides a few extensions of this base class:

Hierarchy of Django unit testing classes (TestCase subclasses)

Hierarchy of Django unit testing classes

You can convert a normal unittest.TestCase to any of the subclasses: change the base class of your test from unittest.TestCase to the subclass. All of the standard Python unit test functionality will be available, and it will be augmented with some useful additions as described in each section below.

SimpleTestCase

class SimpleTestCase[source]

A subclass of unittest.TestCase that adds this functionality:

  • Some useful assertions like:
    • Checking that a callable raises a certain exception.
    • Checking that a callable triggers a certain warning.
    • Testing form field rendering and error treatment.
    • Testing HTML responses for the presence/lack of a given fragment.
    • Verifying that a template has/hasn’t been used to generate a given response content.
    • Verifying that two URLs are equal.
    • Verifying an HTTP redirect is performed by the app.
    • Robustly testing two HTML fragments for equality/inequality or containment.
    • Robustly testing two XML fragments for equality/inequality.
    • Robustly testing two JSON fragments for equality.
  • The ability to run tests with modified settings.
  • Using the client Client.

If your tests make any database queries, use subclasses TransactionTestCase or TestCase.

SimpleTestCase.databases

SimpleTestCase disallows database queries by default. This helps to avoid executing write queries which will affect other tests since each SimpleTestCase test isn’t run in a transaction. If you aren’t concerned about this problem, you can disable this behavior by setting the databases class attribute to '__all__' on your test class.

Warning

SimpleTestCase and its subclasses (e.g. TestCase, …) rely on setUpClass() and tearDownClass() to perform some class-wide initialization (e.g. overriding settings). If you need to override those methods, don’t forget to call the super implementation:

class MyTestCase(TestCase):
    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        ...

    @classmethod
    def tearDownClass(cls):
        ...
        super().tearDownClass()

Be sure to account for Python’s behavior if an exception is raised during setUpClass(). If that happens, neither the tests in the class nor tearDownClass() are run. In the case of django.test.TestCase, this will leak the transaction created in super() which results in various symptoms including a segmentation fault on some platforms (reported on macOS). If you want to intentionally raise an exception such as unittest.SkipTest in setUpClass(), be sure to do it before calling super() to avoid this.

TransactionTestCase

class TransactionTestCase[source]

TransactionTestCase inherits from SimpleTestCase to add some database-specific features:

  • Resetting the database to a known state at the beginning of each test to ease testing and using the ORM.
  • Database fixtures.
  • Test skipping based on database backend features.
  • The remaining specialized assert* methods.

Django’s TestCase class is a more commonly used subclass of TransactionTestCase that makes use of database transaction facilities to speed up the process of resetting the database to a known state at the beginning of each test. A consequence of this, however, is that some database behaviors cannot be tested within a Django TestCase class. For instance, you cannot test that a block of code is executing within a transaction, as is required when using select_for_update(). In those cases, you should use TransactionTestCase.

TransactionTestCase and TestCase are identical except for the manner in which the database is reset to a known state and the ability for test code to test the effects of commit and rollback:

  • A TransactionTestCase resets the database after the test runs by truncating all tables. A TransactionTestCase may call commit and rollback and observe the effects of these calls on the database.
  • A TestCase, on the other hand, does not truncate tables after a test. Instead, it encloses the test code in a database transaction that is rolled back at the end of the test. This guarantees that the rollback at the end of the test restores the database to its initial state.

Warning

TestCase running on a database that does not support rollback (e.g. MySQL with the MyISAM storage engine), and all instances of TransactionTestCase, will roll back at the end of the test by deleting all data from the test database.

Apps will not see their data reloaded; if you need this functionality (for example, third-party apps should enable this) you can set serialized_rollback = True inside the TestCase body.

TestCase

class TestCase[source]

This is the most common class to use for writing tests in Django. It inherits from TransactionTestCase (and by extension SimpleTestCase). If your Django application doesn’t use a database, use SimpleTestCase.

The class:

  • Wraps the tests within two nested atomic() blocks: one for the whole class and one for each test. Therefore, if you want to test some specific database transaction behavior, use TransactionTestCase.
  • Checks deferrable database constraints at the end of each test.

It also provides an additional method:

classmethod TestCase.setUpTestData()[source]

The class-level atomic block described above allows the creation of initial data at the class level, once for the whole TestCase. This technique allows for faster tests as compared to using setUp().

For example:

from django.test import TestCase

class MyTests(TestCase):
    @classmethod
    def setUpTestData(cls):
        # Set up data for the whole TestCase
        cls.foo = Foo.objects.create(bar="Test")
        ...

    def test1(self):
        # Some test using self.foo
        ...

    def test2(self):
        # Some other test using self.foo
        ...

Note that if the tests are run on a database with no transaction support (for instance, MySQL with the MyISAM engine), setUpTestData() will be called before each test, negating the speed benefits.

Objects assigned to class attributes in setUpTestData() must support creating deep copies with copy.deepcopy() in order to isolate them from alterations performed by each test methods.

classmethod TestCase.captureOnCommitCallbacks(using=DEFAULT_DB_ALIAS , execute=False)[source]

Returns a context manager that captures transaction.on_commit() callbacks for the given database connection. It returns a list that contains, on exit of the context, the captured callback functions. From this list you can make assertions on the callbacks or call them to invoke their side effects, emulating a commit.

using is the alias of the database connection to capture callbacks for.

If execute is True, all the callbacks will be called as the context manager exits, if no exception occurred. This emulates a commit after the wrapped block of code.

For example:

from django.core import mail
from django.test import TestCase

class ContactTests(TestCase):
    def test_post(self):
        with self.captureOnCommitCallbacks(execute=True) as callbacks:
            response = self.client.post(
                "/contact/",
                {"message": "I like your site"},
            )

        self.assertEqual(response.status_code, 200)
        self.assertEqual(len(callbacks), 1)
        self.assertEqual(len(mail.outbox), 1)
        self.assertEqual(mail.outbox[0].subject, "Contact Form")
        self.assertEqual(mail.outbox[0].body, "I like your site")

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