- Language: en
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 aUser-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 theheaders
parameter should be preferred for readability.The values from the
headers
,query_params
, andextra
keyword arguments passed toget()
,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 toTrue
.The
json_encoder
argument allows setting a custom JSON encoder for the JSON serialization that’s described inpost()
.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 aResponse
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 thedjango.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
toTrue
the client will follow any redirects and aredirect_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
toTrue
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 aResponse
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, thedata
is serialized usingjson.dumps()
if it’s a dict, list, or tuple. Serialization is performed withDjangoJSONEncoder
by default, and can be overridden by providing ajson_encoder
argument toClient
. This serialization also happens forput()
,patch()
, anddelete()
requests.If you provide any other
content_type
(e.g. text/xml for an XML payload), the contents ofdata
are sent as-is in the POST request, usingcontent_type
in the HTTPContent-Type
header.If you don’t provide a value for
content_type
, the values indata
will be transmitted with a content type of multipart/form-data. In this case, the key-value pairs indata
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 ofdata
would submit three selected values for the field namedchoices
:{"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
andattachment
, the latter aFileField
:>>> 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
orBytesIO
) as a file handle. If you’re uploading to anImageField
, the object needs aname
attribute that passes thevalidate_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 topost()
, 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
, andextra
parameters acts the same as forClient.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
toTrue
the client will follow any redirects and aredirect_chain
attribute will be set in the response object containing tuples of the intermediate urls and status codes.If you set
secure
toTrue
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 aResponse
object. This method works just likeClient.get()
, including thefollow
,secure
,headers
,query_params
, andextra
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 aResponse
object. Useful for testing RESTful interfaces.When
data
is provided, it is used as the request body, and aContent-Type
header is set tocontent_type
.The
follow
,secure
,headers
,query_params
, andextra
parameters act the same as forClient.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 aResponse
object. Useful for testing RESTful interfaces.When
data
is provided, it is used as the request body, and aContent-Type
header is set tocontent_type
.The
follow
,secure
,headers
,query_params
, andextra
parameters act the same as forClient.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 aResponse
object. Useful for testing RESTful interfaces.The
follow
,secure
,headers
,query_params
, andextra
parameters act the same as forClient.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 aResponse
object. Useful for testing RESTful interfaces.When
data
is provided, it is used as the request body, and aContent-Type
header is set tocontent_type
.The
follow
,secure
,headers
,query_params
, andextra
parameters act the same as forClient.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 aResponse
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
, andextra
parameters act the same as forClient.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 yourAUTHENTICATION_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()
returnsTrue
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 thecreate_user()
helper method to create a new user with a correctly hashed password.
-
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 oflogin()
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 thebackend
argument (which should be a dotted Python path string), or tosettings.AUTHENTICATION_BACKENDS[0]
if a value isn’t provided. Theauthenticate()
function called bylogin()
normally annotates the user like this.This method is faster than
login()
since the expensive password hashing algorithms are bypassed. Also, you can speed uplogin()
by using a weaker hasher while testing.
-
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
.
-
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 ofContext
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 variablename
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 beNone
.
-
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 aValueError
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, usetemplate.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 thefunc
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 thehttp.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()
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
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:
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
¶
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 orcontainment
. - Robustly testing two
XML fragments
for equality/inequality. - Robustly testing two
JSON fragments
for equality.
- Checking that a callable
- 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 eachSimpleTestCase
test isn’t run in a transaction. If you aren’t concerned about this problem, you can disable this behavior by setting thedatabases
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
¶
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. ATransactionTestCase
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
¶
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, useTransactionTestCase
. - 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 wholeTestCase
. This technique allows for faster tests as compared to usingsetUp()
.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 withcopy.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
isTrue
, 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")
LiveServerTestCase
¶
LiveServerTestCase
does basically the same as
TransactionTestCase
with one extra feature: it launches a
live Django server in the background on setup, and shuts it down on teardown.
This allows the use of automated test clients other than the
Django dummy client such as, for example, the Selenium
client, to execute a series of functional tests inside a browser and simulate a
real user’s actions.
The live server listens on localhost
and binds to port 0 which uses a free
port assigned by the operating system. The server’s URL can be accessed with
self.live_server_url
during the tests.
To demonstrate how to use LiveServerTestCase
, let’s write a Selenium test.
First of all, you need to install the selenium package:
$ python -m pip install "selenium >= 4.8.0"
...\> py -m pip install "selenium >= 4.8.0"
Then, add a LiveServerTestCase
-based test to your app’s tests module
(for example: myapp/tests.py
). For this example, we’ll assume you’re using
the staticfiles
app and want to have static files served
during the execution of your tests similar to what we get at development time
with DEBUG=True
, i.e. without having to collect them using
collectstatic
. We’ll use
the StaticLiveServerTestCase
subclass which provides that functionality. Replace it with
django.test.LiveServerTestCase
if you don’t need that.
The code for this test may look as follows:
from django.contrib.staticfiles.testing import StaticLiveServerTestCase
from selenium.webdriver.common.by import By
from selenium.webdriver.firefox.webdriver import WebDriver
class MySeleniumTests(StaticLiveServerTestCase):
fixtures = ["user-data.json"]
@classmethod
def setUpClass(cls):
super().setUpClass()
cls.selenium = WebDriver()
cls.selenium.implicitly_wait(10)
@classmethod
def tearDownClass(cls):
cls.selenium.quit()
super().tearDownClass()
def test_login(self):
self.selenium.get(f"{self.live_server_url}/login/")
username_input = self.selenium.find_element(By.NAME, "username")
username_input.send_keys("myuser")
password_input = self.selenium.find_element(By.NAME, "password")
password_input.send_keys("secret")
self.selenium.find_element(By.XPATH, '//input[@value="Log in"]').click()
Finally, you may run the test as follows:
$ ./manage.py test myapp.tests.MySeleniumTests.test_login
...\> manage.py test myapp.tests.MySeleniumTests.test_login
This example will automatically open Firefox then go to the login page, enter the credentials and press the “Log in” button. Selenium offers other drivers in case you do not have Firefox installed or wish to use another browser. The example above is just a tiny fraction of what the Selenium client can do; check out the full reference for more details.
Note
When using an in-memory SQLite database to run the tests, the same database
connection will be shared by two threads in parallel: the thread in which
the live server is run and the thread in which the test case is run. It’s
important to prevent simultaneous database queries via this shared
connection by the two threads, as that may sometimes randomly cause the
tests to fail. So you need to ensure that the two threads don’t access the
database at the same time. In particular, this means that in some cases
(for example, just after clicking a link or submitting a form), you might
need to check that a response is received by Selenium and that the next
page is loaded before proceeding with further test execution.
Do this, for example, by making Selenium wait until the <body>
HTML tag
is found in the response (requires Selenium > 2.13):
def test_login(self):
from selenium.webdriver.support.wait import WebDriverWait
timeout = 2
...
self.selenium.find_element(By.XPATH, '//input[@value="Log in"]').click()
# Wait until the response is received
WebDriverWait(self.selenium, timeout).until(
lambda driver: driver.find_element(By.TAG_NAME, "body")
)
The tricky thing here is that there’s really no such thing as a “page load,”
especially in modern web apps that generate HTML dynamically after the
server generates the initial document. So, checking for the presence of
<body>
in the response might not necessarily be appropriate for all use
cases. Please refer to the Selenium FAQ and Selenium documentation
for more information.
Test cases features¶
Default test client¶
-
SimpleTestCase.
client
¶
Every test case in a django.test.*TestCase
instance has access to an
instance of a Django test client. This client can be accessed as
self.client
. This client is recreated for each test, so you don’t have to
worry about state (such as cookies) carrying over from one test to another.
This means, instead of instantiating a Client
in each test:
import unittest
from django.test import Client
class SimpleTest(unittest.TestCase):
def test_details(self):
client = Client()
response = client.get("/customer/details/")
self.assertEqual(response.status_code, 200)
def test_index(self):
client = Client()
response = client.get("/customer/index/")
self.assertEqual(response.status_code, 200)
…you can refer to self.client
, like so:
from django.test import TestCase
class SimpleTest(TestCase):
def test_details(self):
response = self.client.get("/customer/details/")
self.assertEqual(response.status_code, 200)
def test_index(self):
response = self.client.get("/customer/index/")
self.assertEqual(response.status_code, 200)
Customizing the test client¶
-
SimpleTestCase.
client_class
¶
If you want to use a different Client
class (for example, a subclass
with customized behavior), use the client_class
class
attribute:
from django.test import Client, TestCase
class MyTestClient(Client):
# Specialized methods for your environment
...
class MyTest(TestCase):
client_class = MyTestClient
def test_my_stuff(self):
# Here self.client is an instance of MyTestClient...
call_some_test_code()
Fixture loading¶
-
TransactionTestCase.
fixtures
¶
A test case class for a database-backed website isn’t much use if there isn’t
any data in the database. Tests are more readable and it’s more maintainable to
create objects using the ORM, for example in TestCase.setUpTestData()
,
however, you can also use fixtures.
A fixture is a collection of data that Django knows how to import into a database. For example, if your site has user accounts, you might set up a fixture of fake user accounts in order to populate your database during tests.
The most straightforward way of creating a fixture is to use the
manage.py dumpdata
command. This assumes you
already have some data in your database. See the dumpdata
documentation
for more details.
Once you’ve created a fixture and placed it in a fixtures
directory in one
of your INSTALLED_APPS
, you can use it in your unit tests by
specifying a fixtures
class attribute on your django.test.TestCase
subclass:
from django.test import TestCase
from myapp.models import Animal
class AnimalTestCase(TestCase):
fixtures = ["mammals.json", "birds"]
def setUp(self):
# Test definitions as before.
call_setup_methods()
def test_fluffy_animals(self):
# A test that uses the fixtures.
call_some_test_code()
Here’s specifically what will happen:
- During
setUpClass()
, all the named fixtures are installed. In this example, Django will install any JSON fixture namedmammals
, followed by any fixture namedbirds
. See the Fixtures topic for more details on defining and installing fixtures.
For most unit tests using TestCase
, Django doesn’t need to do
anything else, because transactions are used to clean the database after each
test for performance reasons. But for TransactionTestCase
, the
following actions will take place:
- At the end of each test Django will flush the database, returning the
database to the state it was in directly after
migrate
was called. - For each subsequent test, the fixtures will be reloaded before
setUp()
is run.
In any case, you can be certain that the outcome of a test will not be affected by another test or by the order of test execution.
By default, fixtures are only loaded into the default
database. If you are
using multiple databases and set TransactionTestCase.databases
,
fixtures will be loaded into all specified databases.
For TransactionTestCase
, fixtures were made available during
setUpClass()
.
URLconf configuration¶
If your application provides views, you may want to include tests that use the
test client to exercise those views. However, an end user is free to deploy the
views in your application at any URL of their choosing. This means that your
tests can’t rely upon the fact that your views will be available at a
particular URL. Decorate your test class or test method with
@override_settings(ROOT_URLCONF=...)
for URLconf configuration.
Multi-database support¶
-
TransactionTestCase.
databases
¶
Django sets up a test database corresponding to every database that is
defined in the DATABASES
definition in your settings and referred to
by at least one test through databases
.
However, a big part of the time taken to run a Django TestCase
is consumed
by the call to flush
that ensures that you have a clean database at the
start of each test run. If you have multiple databases, multiple flushes are
required (one for each database), which can be a time consuming activity –
especially if your tests don’t need to test multi-database activity.
As an optimization, Django only flushes the default
database at
the start of each test run. If your setup contains multiple databases,
and you have a test that requires every database to be clean, you can
use the databases
attribute on the test suite to request extra databases
to be flushed.
For example:
class TestMyViews(TransactionTestCase):
databases = {"default", "other"}
def test_index_page_view(self):
call_some_test_code()
This test case class will flush the default
and other
test databases
before running test_index_page_view
. You can also use '__all__'
to
specify that all of the test databases must be flushed.
The databases
flag also controls which databases the
TransactionTestCase.fixtures
are loaded into. By default, fixtures are
only loaded into the default
database.
Queries against databases not in databases
will give assertion errors to
prevent state leaking between tests.
-
TestCase.
databases
¶
By default, only the default
database will be wrapped in a transaction
during a TestCase
’s execution and attempts to query other databases will
result in assertion errors to prevent state leaking between tests.
Use the databases
class attribute on the test class to request transaction
wrapping against non-default
databases.
For example:
class OtherDBTests(TestCase):
databases = {"other"}
def test_other_db_query(self): ...
This test will only allow queries against the other
database. Just like for
SimpleTestCase.databases
and TransactionTestCase.databases
, the
'__all__'
constant can be used to specify that the test should allow
queries to all databases.
Overriding settings¶
Warning
Use the functions below to temporarily alter the value of settings in tests.
Don’t manipulate django.conf.settings
directly as Django won’t restore
the original values after such manipulations.
For testing purposes it’s often useful to change a setting temporarily and
revert to the original value after running the testing code. For this use case
Django provides a standard Python context manager (see PEP 343) called
settings()
, which can be used like this:
from django.test import TestCase
class LoginTestCase(TestCase):
def test_login(self):
# First check for the default behavior
response = self.client.get("/sekrit/")
self.assertRedirects(response, "/accounts/login/?next=/sekrit/")
# Then override the LOGIN_URL setting
with self.settings(LOGIN_URL="/other/login/"):
response = self.client.get("/sekrit/")
self.assertRedirects(response, "/other/login/?next=/sekrit/")
This example will override the LOGIN_URL
setting for the code
in the with
block and reset its value to the previous state afterward.
It can prove unwieldy to redefine settings that contain a list of values. In
practice, adding or removing values is often sufficient. Django provides the
modify_settings()
context manager for easier
settings changes:
from django.test import TestCase
class MiddlewareTestCase(TestCase):
def test_cache_middleware(self):
with self.modify_settings(
MIDDLEWARE={
"append": "django.middleware.cache.FetchFromCacheMiddleware",
"prepend": "django.middleware.cache.UpdateCacheMiddleware",
"remove": [
"django.contrib.sessions.middleware.SessionMiddleware",
"django.contrib.auth.middleware.AuthenticationMiddleware",
"django.contrib.messages.middleware.MessageMiddleware",
],
}
):
response = self.client.get("/")
# ...
For each action, you can supply either a list of values or a string. When the
value already exists in the list, append
and prepend
have no effect;
neither does remove
when the value doesn’t exist.
In case you want to override a setting for a test method, Django provides the
override_settings()
decorator (see PEP 318). It’s used
like this:
from django.test import TestCase, override_settings
class LoginTestCase(TestCase):
@override_settings(LOGIN_URL="/other/login/")
def test_login(self):
response = self.client.get("/sekrit/")
self.assertRedirects(response, "/other/login/?next=/sekrit/")
The decorator can also be applied to TestCase
classes:
from django.test import TestCase, override_settings
@override_settings(LOGIN_URL="/other/login/")
class LoginTestCase(TestCase):
def test_login(self):
response = self.client.get("/sekrit/")
self.assertRedirects(response, "/other/login/?next=/sekrit/")
Likewise, Django provides the modify_settings()
decorator:
from django.test import TestCase, modify_settings
class MiddlewareTestCase(TestCase):
@modify_settings(
MIDDLEWARE={
"append": "django.middleware.cache.FetchFromCacheMiddleware",
"prepend": "django.middleware.cache.UpdateCacheMiddleware",
}
)
def test_cache_middleware(self):
response = self.client.get("/")
# ...
The decorator can also be applied to test case classes:
from django.test import TestCase, modify_settings
@modify_settings(
MIDDLEWARE={
"append": "django.middleware.cache.FetchFromCacheMiddleware",
"prepend": "django.middleware.cache.UpdateCacheMiddleware",
}
)
class MiddlewareTestCase(TestCase):
def test_cache_middleware(self):
response = self.client.get("/")
# ...
Note
When given a class, these decorators modify the class directly and return
it; they don’t create and return a modified copy of it. So if you try to
tweak the above examples to assign the return value to a different name
than LoginTestCase
or MiddlewareTestCase
, you may be surprised to
find that the original test case classes are still equally affected by the
decorator. For a given class, modify_settings()
is
always applied after override_settings()
.
Warning
The settings file contains some settings that are only consulted during
initialization of Django internals. If you change them with
override_settings
, the setting is changed if you access it via the
django.conf.settings
module, however, Django’s internals access it
differently. Effectively, using override_settings()
or
modify_settings()
with these settings is probably not
going to do what you expect it to do.
We do not recommend altering the DATABASES
setting. Altering
the CACHES
setting is possible, but a bit tricky if you are
using internals that make using of caching, like
django.contrib.sessions
. For example, you will have to reinitialize
the session backend in a test that uses cached sessions and overrides
CACHES
.
Finally, avoid aliasing your settings as module-level constants as
override_settings()
won’t work on such values since they are
only evaluated the first time the module is imported.
You can also simulate the absence of a setting by deleting it after settings have been overridden, like this:
@override_settings()
def test_something(self):
del settings.LOGIN_URL
...
When overriding settings, make sure to handle the cases in which your app’s
code uses a cache or similar feature that retains state even if the setting is
changed. Django provides the django.test.signals.setting_changed
signal that lets you register callbacks to clean up and otherwise reset state
when settings are changed.
Django itself uses this signal to reset various data:
Overridden settings | Data reset |
---|---|
USE_TZ, TIME_ZONE | Databases timezone |
TEMPLATES | Template engines |
FORM_RENDERER | Default renderer |
SERIALIZATION_MODULES | Serializers cache |
LOCALE_PATHS, LANGUAGE_CODE | Default translation and loaded translations |
STATIC_ROOT, STATIC_URL, STORAGES | Storages configuration |
Resetting the default renderer when the FORM_RENDERER
setting is
changed was added.
Isolating apps¶
-
utils.
isolate_apps
(*app_labels, attr_name=None, kwarg_name=None)¶ Registers the models defined within a wrapped context into their own isolated
apps
registry. This functionality is useful when creating model classes for tests, as the classes will be cleanly deleted afterward, and there is no risk of name collisions.The app labels which the isolated registry should contain must be passed as individual arguments. You can use
isolate_apps()
as a decorator or a context manager. For example:from django.db import models from django.test import SimpleTestCase from django.test.utils import isolate_apps class MyModelTests(SimpleTestCase): @isolate_apps("app_label") def test_model_definition(self): class TestModel(models.Model): pass ...
… or:
with isolate_apps("app_label"): class TestModel(models.Model): pass ...
The decorator form can also be applied to classes.
Two optional keyword arguments can be specified:
attr_name
: attribute assigned the isolated registry if used as a class decorator.kwarg_name
: keyword argument passing the isolated registry if used as a function decorator.
The temporary
Apps
instance used to isolate model registration can be retrieved as an attribute when used as a class decorator by using theattr_name
parameter:@isolate_apps("app_label", attr_name="apps") class TestModelDefinition(SimpleTestCase): def test_model_definition(self): class TestModel(models.Model): pass self.assertIs(self.apps.get_model("app_label", "TestModel"), TestModel)
… or alternatively as an argument on the test method when used as a method decorator by using the
kwarg_name
parameter:class TestModelDefinition(SimpleTestCase): @isolate_apps("app_label", kwarg_name="apps") def test_model_definition(self, apps): class TestModel(models.Model): pass self.assertIs(apps.get_model("app_label", "TestModel"), TestModel)
Emptying the test outbox¶
If you use any of Django’s custom TestCase
classes, the test runner will
clear the contents of the test email outbox at the start of each test case.
For more detail on email services during tests, see Email services below.
Assertions¶
As Python’s normal unittest.TestCase
class implements assertion methods
such as assertTrue()
and
assertEqual()
, Django’s custom TestCase
class
provides a number of custom assertion methods that are useful for testing web
applications:
The failure messages given by most of these assertion methods can be customized
with the msg_prefix
argument. This string will be prefixed to any failure
message generated by the assertion. This allows you to provide additional
details that may help you to identify the location and cause of a failure in
your test suite.
-
SimpleTestCase.
assertRaisesMessage
(expected_exception, expected_message, callable, *args, **kwargs)[source]¶ -
SimpleTestCase.
assertRaisesMessage
(expected_exception, expected_message) Asserts that execution of
callable
raisesexpected_exception
and thatexpected_message
is found in the exception’s message. Any other outcome is reported as a failure. It’s a simpler version ofunittest.TestCase.assertRaisesRegex()
with the difference thatexpected_message
isn’t treated as a regular expression.If only the
expected_exception
andexpected_message
parameters are given, returns a context manager so that the code being tested can be written inline rather than as a function:with self.assertRaisesMessage(ValueError, "invalid literal for int()"): int("a")
-
SimpleTestCase.
assertWarnsMessage
(expected_warning, expected_message, callable, *args, **kwargs)[source]¶ -
SimpleTestCase.
assertWarnsMessage
(expected_warning, expected_message) Analogous to
SimpleTestCase.assertRaisesMessage()
but forassertWarnsRegex()
instead ofassertRaisesRegex()
.
-
SimpleTestCase.
assertFieldOutput
(fieldclass, valid, invalid, field_args=None, field_kwargs=None, empty_value='')[source]¶ Asserts that a form field behaves correctly with various inputs.
Parameters: - fieldclass – the class of the field to be tested.
- valid – a dictionary mapping valid inputs to their expected cleaned values.
- invalid – a dictionary mapping invalid inputs to one or more raised error messages.
- field_args – the args passed to instantiate the field.
- field_kwargs – the kwargs passed to instantiate the field.
- empty_value – the expected clean output for inputs in
empty_values
.
For example, the following code tests that an
EmailField
acceptsa@a.com
as a valid email address, but rejectsaaa
with a reasonable error message:self.assertFieldOutput( EmailField, {"a@a.com": "a@a.com"}, {"aaa": ["Enter a valid email address."]} )
-
SimpleTestCase.
assertFormError
(form, field, errors, msg_prefix='')[source]¶ Asserts that a field on a form raises the provided list of errors.
form
is aForm
instance. The form must be bound but not necessarily validated (assertFormError()
will automatically callfull_clean()
on the form).field
is the name of the field on the form to check. To check the form’snon-field errors
, usefield=None
.errors
is a list of all the error strings that the field is expected to have. You can also pass a single error string if you only expect one error which means thaterrors='error message'
is the same aserrors=['error message']
.
-
SimpleTestCase.
assertFormSetError
(formset, form_index, field, errors, msg_prefix='')[source]¶ Asserts that the
formset
raises the provided list of errors when rendered.formset
is aFormSet
instance. The formset must be bound but not necessarily validated (assertFormSetError()
will automatically call thefull_clean()
on the formset).form_index
is the number of the form within theFormSet
(starting from 0). Useform_index=None
to check the formset’s non-form errors, i.e. the errors you get when callingformset.non_form_errors()
. In that case you must also usefield=None
.field
anderrors
have the same meaning as the parameters toassertFormError()
.
-
SimpleTestCase.
assertContains
(response, text, count=None, status_code=200, msg_prefix='', html=False)[source]¶ Asserts that a
response
produced the givenstatus_code
and thattext
appears in itscontent
. Ifcount
is provided,text
must occur exactlycount
times in the response.Set
html
toTrue
to handletext
as HTML. The comparison with the response content will be based on HTML semantics instead of character-by-character equality. Whitespace is ignored in most cases, attribute ordering is not significant. SeeassertHTMLEqual()
for more details.Changed in Django 5.1:In older versions, error messages didn’t contain the response content.
-
SimpleTestCase.
assertNotContains
(response, text, status_code=200, msg_prefix='', html=False)[source]¶ Asserts that a
response
produced the givenstatus_code
and thattext
does not appear in itscontent
.Set
html
toTrue
to handletext
as HTML. The comparison with the response content will be based on HTML semantics instead of character-by-character equality. Whitespace is ignored in most cases, attribute ordering is not significant. SeeassertHTMLEqual()
for more details.Changed in Django 5.1:In older versions, error messages didn’t contain the response content.
-
SimpleTestCase.
assertTemplateUsed
(response, template_name, msg_prefix='', count=None)[source]¶ Asserts that the template with the given name was used in rendering the response.
response
must be a response instance returned by thetest client
.template_name
should be a string such as'admin/index.html'
.The
count
argument is an integer indicating the number of times the template should be rendered. Default isNone
, meaning that the template should be rendered one or more times.You can use this as a context manager, like this:
with self.assertTemplateUsed("index.html"): render_to_string("index.html") with self.assertTemplateUsed(template_name="index.html"): render_to_string("index.html")
-
SimpleTestCase.
assertTemplateNotUsed
(response, template_name, msg_prefix='')[source]¶ Asserts that the template with the given name was not used in rendering the response.
You can use this as a context manager in the same way as
assertTemplateUsed()
.
-
SimpleTestCase.
assertURLEqual
(url1, url2, msg_prefix='')[source]¶ Asserts that two URLs are the same, ignoring the order of query string parameters except for parameters with the same name. For example,
/path/?x=1&y=2
is equal to/path/?y=2&x=1
, but/path/?a=1&a=2
isn’t equal to/path/?a=2&a=1
.
-
SimpleTestCase.
assertRedirects
(response, expected_url, status_code=302, target_status_code=200, msg_prefix='', fetch_redirect_response=True)[source]¶ Asserts that the
response
returned astatus_code
redirect status, redirected toexpected_url
(including anyGET
data), and that the final page was received withtarget_status_code
.If your request used the
follow
argument, theexpected_url
andtarget_status_code
will be the url and status code for the final point of the redirect chain.If
fetch_redirect_response
isFalse
, the final page won’t be loaded. Since the test client can’t fetch external URLs, this is particularly useful ifexpected_url
isn’t part of your Django app.Scheme is handled correctly when making comparisons between two URLs. If there isn’t any scheme specified in the location where we are redirected to, the original request’s scheme is used. If present, the scheme in
expected_url
is the one used to make the comparisons to.
-
SimpleTestCase.
assertHTMLEqual
(html1, html2, msg=None)[source]¶ Asserts that the strings
html1
andhtml2
are equal. The comparison is based on HTML semantics. The comparison takes following things into account:- Whitespace before and after HTML tags is ignored.
- All types of whitespace are considered equivalent.
- All open tags are closed implicitly, e.g. when a surrounding tag is closed or the HTML document ends.
- Empty tags are equivalent to their self-closing version.
- The ordering of attributes of an HTML element is not significant.
- Boolean attributes (like
checked
) without an argument are equal to attributes that equal in name and value (see the examples). - Text, character references, and entity references that refer to the same character are equivalent.
The following examples are valid tests and don’t raise any
AssertionError
:self.assertHTMLEqual( "<p>Hello <b>'world'!</p>", """<p> Hello <b>'world'! </b> </p>""", ) self.assertHTMLEqual( '<input type="checkbox" checked="checked" id="id_accept_terms" />', '<input id="id_accept_terms" type="checkbox" checked>', )
html1
andhtml2
must contain HTML. AnAssertionError
will be raised if one of them cannot be parsed.Output in case of error can be customized with the
msg
argument.
-
SimpleTestCase.
assertHTMLNotEqual
(html1, html2, msg=None)[source]¶ Asserts that the strings
html1
andhtml2
are not equal. The comparison is based on HTML semantics. SeeassertHTMLEqual()
for details.html1
andhtml2
must contain HTML. AnAssertionError
will be raised if one of them cannot be parsed.Output in case of error can be customized with the
msg
argument.
-
SimpleTestCase.
assertXMLEqual
(xml1, xml2, msg=None)[source]¶ Asserts that the strings
xml1
andxml2
are equal. The comparison is based on XML semantics. Similarly toassertHTMLEqual()
, the comparison is made on parsed content, hence only semantic differences are considered, not syntax differences. When invalid XML is passed in any parameter, anAssertionError
is always raised, even if both strings are identical.XML declaration, document type, processing instructions, and comments are ignored. Only the root element and its children are compared.
Output in case of error can be customized with the
msg
argument.
-
SimpleTestCase.
assertXMLNotEqual
(xml1, xml2, msg=None)[source]¶ Asserts that the strings
xml1
andxml2
are not equal. The comparison is based on XML semantics. SeeassertXMLEqual()
for details.Output in case of error can be customized with the
msg
argument.
-
SimpleTestCase.
assertInHTML
(needle, haystack, count=None, msg_prefix='')[source]¶ Asserts that the HTML fragment
needle
is contained in thehaystack
once.If the
count
integer argument is specified, then additionally the number ofneedle
occurrences will be strictly verified.Whitespace in most cases is ignored, and attribute ordering is not significant. See
assertHTMLEqual()
for more details.Changed in Django 5.1:In older versions, error messages didn’t contain the
haystack
.
-
SimpleTestCase.
assertNotInHTML
(needle, haystack, msg_prefix='')[source]¶ - New in Django 5.1.
Asserts that the HTML fragment
needle
is not contained in thehaystack
.Whitespace in most cases is ignored, and attribute ordering is not significant. See
assertHTMLEqual()
for more details.
-
SimpleTestCase.
assertJSONEqual
(raw, expected_data, msg=None)[source]¶ Asserts that the JSON fragments
raw
andexpected_data
are equal. Usual JSON non-significant whitespace rules apply as the heavyweight is delegated to thejson
library.Output in case of error can be customized with the
msg
argument.
-
SimpleTestCase.
assertJSONNotEqual
(raw, expected_data, msg=None)[source]¶ Asserts that the JSON fragments
raw
andexpected_data
are not equal. SeeassertJSONEqual()
for further details.Output in case of error can be customized with the
msg
argument.
-
TransactionTestCase.
assertQuerySetEqual
(qs, values, transform=None, ordered=True, msg=None)[source]¶ Asserts that a queryset
qs
matches a particular iterable of valuesvalues
.If
transform
is provided,values
is compared to a list produced by applyingtransform
to each member ofqs
.By default, the comparison is also ordering dependent. If
qs
doesn’t provide an implicit ordering, you can set theordered
parameter toFalse
, which turns the comparison into acollections.Counter
comparison. If the order is undefined (if the givenqs
isn’t ordered and the comparison is against more than one ordered value), aValueError
is raised.Output in case of error can be customized with the
msg
argument.
-
TransactionTestCase.
assertNumQueries
(num, func, *args, **kwargs)[source]¶ Asserts that when
func
is called with*args
and**kwargs
thatnum
database queries are executed.If a
"using"
key is present inkwargs
it is used as the database alias for which to check the number of queries:self.assertNumQueries(7, using="non_default_db")
If you wish to call a function with a
using
parameter you can do it by wrapping the call with alambda
to add an extra parameter:self.assertNumQueries(7, lambda: my_function(using=7))
You can also use this as a context manager:
with self.assertNumQueries(2): Person.objects.create(name="Aaron") Person.objects.create(name="Daniel")
Tagging tests¶
You can tag your tests so you can easily run a particular subset. For example, you might label fast or slow tests:
from django.test import tag
class SampleTestCase(TestCase):
@tag("fast")
def test_fast(self): ...
@tag("slow")
def test_slow(self): ...
@tag("slow", "core")
def test_slow_but_core(self): ...
You can also tag a test case class:
@tag("slow", "core")
class SampleTestCase(TestCase): ...
Subclasses inherit tags from superclasses, and methods inherit tags from their class. Given:
@tag("foo")
class SampleTestCaseChild(SampleTestCase):
@tag("bar")
def test(self): ...
SampleTestCaseChild.test
will be labeled with 'slow'
, 'core'
,
'bar'
, and 'foo'
.
Then you can choose which tests to run. For example, to run only fast tests:
$ ./manage.py test --tag=fast
...\> manage.py test --tag=fast
Or to run fast tests and the core one (even though it’s slow):
$ ./manage.py test --tag=fast --tag=core
...\> manage.py test --tag=fast --tag=core
You can also exclude tests by tag. To run core tests if they are not slow:
$ ./manage.py test --tag=core --exclude-tag=slow
...\> manage.py test --tag=core --exclude-tag=slow
test --exclude-tag
has precedence over test --tag
, so if a
test has two tags and you select one of them and exclude the other, the test
won’t be run.
Testing asynchronous code¶
If you merely want to test the output of your asynchronous views, the standard test client will run them inside their own asynchronous loop without any extra work needed on your part.
However, if you want to write fully-asynchronous tests for a Django project, you will need to take several things into account.
Firstly, your tests must be async def
methods on the test class (in order
to give them an asynchronous context). Django will automatically detect
any async def
tests and wrap them so they run in their own event loop.
If you are testing from an asynchronous function, you must also use the
asynchronous test client. This is available as django.test.AsyncClient
,
or as self.async_client
on any test.
-
class
AsyncClient
(enforce_csrf_checks=False, raise_request_exception=True, *, headers=None, query_params=None, **defaults)[source]¶
AsyncClient
has the same methods and signatures as the synchronous (normal)
test client, with the following exceptions:
In the initialization, arbitrary keyword arguments in
defaults
are added directly into the ASGI scope.Headers passed as
extra
keyword arguments should not have theHTTP_
prefix required by the synchronous client (seeClient.get()
). For example, here is how to set an HTTPAccept
header:>>> c = AsyncClient() >>> c.get("/customers/details/", {"name": "fred", "age": 7}, ACCEPT="application/json")
The query_params
argument was added.
Using AsyncClient
any method that makes a request must be awaited:
async def test_my_thing(self):
response = await self.async_client.get("/some-url/")
self.assertEqual(response.status_code, 200)
The asynchronous client can also call synchronous views; it runs through
Django’s asynchronous request path, which supports both.
Any view called through the AsyncClient
will get an ASGIRequest
object
for its request
rather than the WSGIRequest
that the normal client
creates.
Warning
If you are using test decorators, they must be async-compatible to ensure they work correctly. Django’s built-in decorators will behave correctly, but third-party ones may appear to not execute (they will “wrap” the wrong part of the execution flow and not your test).
If you need to use these decorators, then you should decorate your test
methods with async_to_sync()
inside of them instead:
from asgiref.sync import async_to_sync
from django.test import TestCase
class MyTests(TestCase):
@mock.patch(...)
@async_to_sync
async def test_my_thing(self): ...
Email services¶
If any of your Django views send email using Django’s email functionality, you probably don’t want to send email each time you run a test using that view. For this reason, Django’s test runner automatically redirects all Django-sent email to a dummy outbox. This lets you test every aspect of sending email – from the number of messages sent to the contents of each message – without actually sending the messages.
The test runner accomplishes this by transparently replacing the normal email backend with a testing backend. (Don’t worry – this has no effect on any other email senders outside of Django, such as your machine’s mail server, if you’re running one.)
-
django.core.mail.
outbox
¶
During test running, each outgoing email is saved in
django.core.mail.outbox
. This is a list of all
EmailMessage
instances that have been sent. The
outbox
attribute is a special attribute that is created only when the
locmem
email backend is used. It doesn’t normally exist as part of the
django.core.mail
module and you can’t import it directly. The code below
shows how to access this attribute correctly.
Here’s an example test that examines django.core.mail.outbox
for length
and contents:
from django.core import mail
from django.test import TestCase
class EmailTest(TestCase):
def test_send_email(self):
# Send message.
mail.send_mail(
"Subject here",
"Here is the message.",
"from@example.com",
["to@example.com"],
fail_silently=False,
)
# Test that one message has been sent.
self.assertEqual(len(mail.outbox), 1)
# Verify that the subject of the first message is correct.
self.assertEqual(mail.outbox[0].subject, "Subject here")
As noted previously, the test outbox is emptied
at the start of every test in a Django *TestCase
. To empty the outbox
manually, assign the empty list to mail.outbox
:
from django.core import mail
# Empty the test outbox
mail.outbox = []
Management Commands¶
Management commands can be tested with the
call_command()
function. The output can be
redirected into a StringIO
instance:
from io import StringIO
from django.core.management import call_command
from django.test import TestCase
class ClosepollTest(TestCase):
def test_command_output(self):
out = StringIO()
call_command("closepoll", poll_ids=[1], stdout=out)
self.assertIn('Successfully closed poll "1"', out.getvalue())
Skipping tests¶
The unittest library provides the @skipIf
and
@skipUnless
decorators to allow you to skip tests
if you know ahead of time that those tests are going to fail under certain
conditions.
For example, if your test requires a particular optional library in order to
succeed, you could decorate the test case with @skipIf
. Then, the test runner will report that the test wasn’t
executed and why, instead of failing the test or omitting the test altogether.
To supplement these test skipping behaviors, Django provides two additional skip decorators. Instead of testing a generic boolean, these decorators check the capabilities of the database, and skip the test if the database doesn’t support a specific named feature.
The decorators use a string identifier to describe database features. This string corresponds to attributes of the database connection features class. See django.db.backends.base.features.BaseDatabaseFeatures class for a full list of database features that can be used as a basis for skipping tests.
Skip the decorated test or TestCase
if all of the named database features
are supported.
For example, the following test will not be executed if the database supports transactions (e.g., it would not run under PostgreSQL, but it would under MySQL with MyISAM tables):
class MyTests(TestCase):
@skipIfDBFeature("supports_transactions")
def test_transaction_behavior(self):
# ... conditional test code
pass
Skip the decorated test or TestCase
if any of the named database features
are not supported.
For example, the following test will only be executed if the database supports transactions (e.g., it would run under PostgreSQL, but not under MySQL with MyISAM tables):
class MyTests(TestCase):
@skipUnlessDBFeature("supports_transactions")
def test_transaction_behavior(self):
# ... conditional test code
pass