import collections

import gc

import logging

import os

import re

import sys

import time

import warnings

from contextlib import contextmanager

from functools import wraps

from io import StringIO

from itertools import chain

from types import SimpleNamespace

from unittest import TestCase, skipIf, skipUnless

from xml.dom.minidom import Node, parseString

from asgiref.sync import iscoroutinefunction

from django.apps import apps

from django.apps.registry import Apps

from django.conf import UserSettingsHolder, settings

from django.core import mail

from django.core.exceptions import ImproperlyConfigured

from django.core.signals import request_started, setting_changed

from django.db import DEFAULT_DB_ALIAS, connections, reset_queries

from django.db.models.options import Options

from django.template import Template

from django.test.signals import template_rendered

from django.urls import get_script_prefix, set_script_prefix

from django.utils.translation import deactivate

from django.utils.version import PYPY

try:

import jinja2

except ImportError:

jinja2 = None

__all__ = (

"Approximate",

"ContextList",

"isolate_lru_cache",

"garbage_collect",

"get_runner",

"CaptureQueriesContext",

"ignore_warnings",

"isolate_apps",

"modify_settings",

"override_settings",

"override_system_checks",

"tag",

"requires_tz_support",

"setup_databases",

"setup_test_environment",

"teardown_test_environment",

)

TZ_SUPPORT = hasattr(time, "tzset")

class Approximate:

def __init__(self, val, places=7):

self.val = val

self.places = places

def __repr__(self):

return repr(self.val)

def __eq__(self, other):

return self.val == other or round(abs(self.val - other), self.places) == 0

class ContextList(list):

"""

A wrapper that provides direct key access to context items contained

in a list of context objects.

"""

def __getitem__(self, key):

if isinstance(key, str):

for subcontext in self:

if key in subcontext:

return subcontext[key]

raise KeyError(key)

else:

return super().__getitem__(key)

def get(self, key, default=None):

try:

return self.__getitem__(key)

except KeyError:

return default

def __contains__(self, key):

try:

self[key]

except KeyError:

return False

return True

def keys(self):

"""

Flattened keys of subcontexts.

"""

return set(chain.from_iterable(d for subcontext in self for d in subcontext))

def instrumented_test_render(self, context):

"""

An instrumented Template render method, providing a signal that can be

intercepted by the test Client.

"""

template_rendered.send(sender=self, template=self, context=context)

return self.nodelist.render(context)

class _TestState:

pass

def setup_test_environment(debug=None):

"""

Perform global pre-test setup, such as installing the instrumented template

renderer and setting the email backend to the locmem email backend.

"""

if hasattr(_TestState, "saved_data"):

# Executing this function twice would overwrite the saved values.

raise RuntimeError(

"setup_test_environment() was already called and can't be called "

"again without first calling teardown_test_environment()."

)

if debug is None:

debug = settings.DEBUG

saved_data = SimpleNamespace()

_TestState.saved_data = saved_data

saved_data.allowed_hosts = settings.ALLOWED_HOSTS

# Add the default host of the test client.

settings.ALLOWED_HOSTS = [*settings.ALLOWED_HOSTS, "testserver"]

saved_data.debug = settings.DEBUG

settings.DEBUG = debug

saved_data.email_backend = settings.EMAIL_BACKEND

settings.EMAIL_BACKEND = "django.core.mail.backends.locmem.EmailBackend"

saved_data.template_render = Template._render

Template._render = instrumented_test_render

mail.outbox = []

deactivate()

def teardown_test_environment():

"""

Perform any global post-test teardown, such as restoring the original

template renderer and restoring the email sending functions.

"""

saved_data = _TestState.saved_data

settings.ALLOWED_HOSTS = saved_data.allowed_hosts

settings.DEBUG = saved_data.debug

settings.EMAIL_BACKEND = saved_data.email_backend

Template._render = saved_data.template_render

del _TestState.saved_data

del mail.outbox

def setup_databases(

verbosity,

interactive,

*,

time_keeper=None,

keepdb=False,

debug_sql=False,

parallel=0,

aliases=None,

serialized_aliases=None,

**kwargs,

):

"""Create the test databases."""

if time_keeper is None:

time_keeper = NullTimeKeeper()

test_databases, mirrored_aliases = get_unique_databases_and_mirrors(aliases)

old_names = []

for db_name, aliases in test_databases.values():

first_alias = None

for alias in aliases:

connection = connections[alias]

old_names.append((connection, db_name, first_alias is None))

# Actually create the database for the first connection

if first_alias is None:

first_alias = alias

with time_keeper.timed(" Creating '%s'" % alias):

serialize_alias = (

serialized_aliases is None or alias in serialized_aliases

)

connection.creation.create_test_db(

verbosity=verbosity,

autoclobber=not interactive,

keepdb=keepdb,

serialize=serialize_alias,

)

if parallel > 1:

for index in range(parallel):

with time_keeper.timed(" Cloning '%s'" % alias):

connection.creation.clone_test_db(

suffix=str(index + 1),

verbosity=verbosity,

keepdb=keepdb,

)

# Configure all other connections as mirrors of the first one

else:

connections[alias].creation.set_as_test_mirror(

connections[first_alias].settings_dict

)

# Configure the test mirrors.

for alias, mirror_alias in mirrored_aliases.items():

connections[alias].creation.set_as_test_mirror(

connections[mirror_alias].settings_dict

)

if debug_sql:

for alias in connections:

connections[alias].force_debug_cursor = True

return old_names

def iter_test_cases(tests):

"""

Return an iterator over a test suite's unittest.TestCase objects.

The tests argument can also be an iterable of TestCase objects.

"""

for test in tests:

if isinstance(test, str):

# Prevent an unfriendly RecursionError that can happen with

# strings.

raise TypeError(

f"Test {test!r} must be a test case or test suite not string "

f"(was found in {tests!r})."

)

if isinstance(test, TestCase):

yield test

else:

# Otherwise, assume it is a test suite.

yield from iter_test_cases(test)

def dependency_ordered(test_databases, dependencies):

"""

Reorder test_databases into an order that honors the dependencies

described in TEST[DEPENDENCIES].

"""

ordered_test_databases = []

resolved_databases = set()

# Maps db signature to dependencies of all its aliases

dependencies_map = {}

# Check that no database depends on its own alias

for sig, (_, aliases) in test_databases:

all_deps = set()

for alias in aliases:

all_deps.update(dependencies.get(alias, []))

if not all_deps.isdisjoint(aliases):

raise ImproperlyConfigured(

"Circular dependency: databases %r depend on each other, "

"but are aliases." % aliases

)

dependencies_map[sig] = all_deps

while test_databases:

changed = False

deferred = []

# Try to find a DB that has all its dependencies met

for signature, (db_name, aliases) in test_databases:

if dependencies_map[signature].issubset(resolved_databases):

resolved_databases.update(aliases)

ordered_test_databases.append((signature, (db_name, aliases)))

changed = True

else:

deferred.append((signature, (db_name, aliases)))

if not changed:

raise ImproperlyConfigured("Circular dependency in TEST[DEPENDENCIES]")

test_databases = deferred

return ordered_test_databases

def get_unique_databases_and_mirrors(aliases=None):

"""

Figure out which databases actually need to be created.

Deduplicate entries in DATABASES that correspond the same database or are

configured as test mirrors.

Return two values:

- test_databases: ordered mapping of signatures to (name, list of aliases)

where all aliases share the same underlying database.

- mirrored_aliases: mapping of mirror aliases to original aliases.

"""

if aliases is None:

aliases = connections

mirrored_aliases = {}

test_databases = {}

dependencies = {}

default_sig = connections[DEFAULT_DB_ALIAS].creation.test_db_signature()

for alias in connections:

connection = connections[alias]

test_settings = connection.settings_dict["TEST"]

if test_settings["MIRROR"]:

# If the database is marked as a test mirror, save the alias.

mirrored_aliases[alias] = test_settings["MIRROR"]

elif alias in aliases:

# Store a tuple with DB parameters that uniquely identify it.

# If we have two aliases with the same values for that tuple,

# we only need to create the test database once.

item = test_databases.setdefault(

connection.creation.test_db_signature(),

(connection.settings_dict["NAME"], []),

)

# The default database must be the first because data migrations

# use the default alias by default.

if alias == DEFAULT_DB_ALIAS:

item[1].insert(0, alias)

else:

item[1].append(alias)

if "DEPENDENCIES" in test_settings:

dependencies[alias] = test_settings["DEPENDENCIES"]

else:

if (

alias != DEFAULT_DB_ALIAS

and connection.creation.test_db_signature() != default_sig

):

dependencies[alias] = test_settings.get(

"DEPENDENCIES", [DEFAULT_DB_ALIAS]

)

test_databases = dict(dependency_ordered(test_databases.items(), dependencies))

return test_databases, mirrored_aliases

def teardown_databases(old_config, verbosity, parallel=0, keepdb=False):

"""Destroy all the non-mirror databases."""

for connection, old_name, destroy in old_config:

if destroy:

if parallel > 1:

for index in range(parallel):

connection.creation.destroy_test_db(

suffix=str(index + 1),

verbosity=verbosity,

keepdb=keepdb,

)

connection.creation.destroy_test_db(old_name, verbosity, keepdb)

def get_runner(settings, test_runner_class=None):

test_runner_class = test_runner_class or settings.TEST_RUNNER

test_path = test_runner_class.split(".")

# Allow for relative paths

if len(test_path) > 1:

test_module_name = ".".join(test_path[:-1])

else:

test_module_name = "."

test_module = __import__(test_module_name, {}, {}, test_path[-1])

return getattr(test_module, test_path[-1])

class TestContextDecorator:

"""

A base class that can either be used as a context manager during tests

or as a test function or unittest.TestCase subclass decorator to perform

temporary alterations.

`attr_name`: attribute assigned the return value of enable() if used as

a class decorator.

`kwarg_name`: keyword argument passing the return value of enable() if

used as a function decorator.

"""

def __init__(self, attr_name=None, kwarg_name=None):

self.attr_name = attr_name

self.kwarg_name = kwarg_name

def enable(self):

raise NotImplementedError

def disable(self):

raise NotImplementedError

def __enter__(self):

return self.enable()

def __exit__(self, exc_type, exc_value, traceback):

self.disable()

def decorate_class(self, cls):

if issubclass(cls, TestCase):

decorated_setUp = cls.setUp

def setUp(inner_self):

context = self.enable()

inner_self.addCleanup(self.disable)

if self.attr_name:

setattr(inner_self, self.attr_name, context)

decorated_setUp(inner_self)

cls.setUp = setUp

return cls

raise TypeError("Can only decorate subclasses of unittest.TestCase")

def decorate_callable(self, func):

if iscoroutinefunction(func):

# If the inner function is an async function, we must execute async

# as well so that the `with` statement executes at the right time.

@wraps(func)

async def inner(*args, **kwargs):

with self as context:

if self.kwarg_name:

kwargs[self.kwarg_name] = context

return await func(*args, **kwargs)

else:

@wraps(func)

def inner(*args, **kwargs):

with self as context:

if self.kwarg_name:

kwargs[self.kwarg_name] = context

return func(*args, **kwargs)

return inner

def __call__(self, decorated):

if isinstance(decorated, type):

return self.decorate_class(decorated)

elif callable(decorated):

return self.decorate_callable(decorated)

raise TypeError("Cannot decorate object of type %s" % type(decorated))

class override_settings(TestContextDecorator):

"""

Act as either a decorator or a context manager. If it's a decorator, take a

function and return a wrapped function. If it's a contextmanager, use it

with the ``with`` statement. In either event, entering/exiting are called

before and after, respectively, the function/block is executed.

"""

enable_exception = None

def __init__(self, **kwargs):

self.options = kwargs

super().__init__()

def enable(self):

# Keep this code at the beginning to leave the settings unchanged

# in case it raises an exception because INSTALLED_APPS is invalid.

if "INSTALLED_APPS" in self.options:

try:

apps.set_installed_apps(self.options["INSTALLED_APPS"])

except Exception:

apps.unset_installed_apps()

raise

override = UserSettingsHolder(settings._wrapped)

for key, new_value in self.options.items():

setattr(override, key, new_value)

self.wrapped = settings._wrapped

settings._wrapped = override

for key, new_value in self.options.items():

try:

setting_changed.send(

sender=settings._wrapped.__class__,

setting=key,

value=new_value,

enter=True,

)

except Exception as exc:

self.enable_exception = exc

self.disable()

def disable(self):

if "INSTALLED_APPS" in self.options:

apps.unset_installed_apps()

settings._wrapped = self.wrapped

del self.wrapped

responses = []

for key in self.options:

new_value = getattr(settings, key, None)

responses_for_setting = setting_changed.send_robust(

sender=settings._wrapped.__class__,

setting=key,

value=new_value,

enter=False,

)

responses.extend(responses_for_setting)

if self.enable_exception is not None:

exc = self.enable_exception

self.enable_exception = None

raise exc

for _, response in responses:

if isinstance(response, Exception):

raise response

def save_options(self, test_func):

if test_func._overridden_settings is None:

test_func._overridden_settings = self.options

else:

# Duplicate dict to prevent subclasses from altering their parent.

test_func._overridden_settings = {

**test_func._overridden_settings,

**self.options,

}

def decorate_class(self, cls):

from django.test import SimpleTestCase

if not issubclass(cls, SimpleTestCase):

raise ValueError(

"Only subclasses of Django SimpleTestCase can be decorated "

"with override_settings"

)

self.save_options(cls)

return cls

class modify_settings(override_settings):

"""

Like override_settings, but makes it possible to append, prepend, or remove

items instead of redefining the entire list.

"""

def __init__(self, *args, **kwargs):

if args:

# Hack used when instantiating from SimpleTestCase.setUpClass.

assert not kwargs

self.operations = args[0]

else:

assert not args

self.operations = list(kwargs.items())

super(override_settings, self).__init__()

def save_options(self, test_func):

if test_func._modified_settings is None:

test_func._modified_settings = self.operations

else:

# Duplicate list to prevent subclasses from altering their parent.

test_func._modified_settings = (

list(test_func._modified_settings) + self.operations

)

def enable(self):

self.options = {}

for name, operations in self.operations:

try:

# When called from SimpleTestCase.setUpClass, values may be

# overridden several times; cumulate changes.

value = self.options[name]

except KeyError:

value = list(getattr(settings, name, []))

for action, items in operations.items():

# items may be a single value or an iterable.

if isinstance(items, str):

items = [items]

if action == "append":

value += [item for item in items if item not in value]

elif action == "prepend":

value = [item for item in items if item not in value] + value

elif action == "remove":

value = [item for item in value if item not in items]

else:

raise ValueError("Unsupported action: %s" % action)

self.options[name] = value

super().enable()

class override_system_checks(TestContextDecorator):

"""

Act as a decorator. Override list of registered system checks.

Useful when you override `INSTALLED_APPS`, e.g. if you exclude `auth` app,

you also need to exclude its system checks.

"""

def __init__(self, new_checks, deployment_checks=None):

from django.core.checks.registry import registry

self.registry = registry

self.new_checks = new_checks

self.deployment_checks = deployment_checks

super().__init__()

def enable(self):

self.old_checks = self.registry.registered_checks

self.registry.registered_checks = set()

for check in self.new_checks:

self.registry.register(check, *getattr(check, "tags", ()))

self.old_deployment_checks = self.registry.deployment_checks

if self.deployment_checks is not None:

self.registry.deployment_checks = set()

for check in self.deployment_checks:

self.registry.register(check, *getattr(check, "tags", ()), deploy=True)

def disable(self):

self.registry.registered_checks = self.old_checks

self.registry.deployment_checks = self.old_deployment_checks

def compare_xml(want, got):

"""

Try to do a 'xml-comparison' of want and got. Plain string comparison

doesn't always work because, for example, attribute ordering should not be

important. Ignore comment nodes, processing instructions, document type

node, and leading and trailing whitespaces.

Based on https://github.com/lxml/lxml/blob/master/src/lxml/doctestcompare.py

"""

_norm_whitespace_re = re.compile(r"[ \t\n][ \t\n]+")

def norm_whitespace(v):

return _norm_whitespace_re.sub(" ", v)

def child_text(element):

return "".join(

c.data for c in element.childNodes if c.nodeType == Node.TEXT_NODE

)

def children(element):

return [c for c in element.childNodes if c.nodeType == Node.ELEMENT_NODE]

def norm_child_text(element):

return norm_whitespace(child_text(element))

def attrs_dict(element):

return dict(element.attributes.items())

def check_element(want_element, got_element):

if want_element.tagName != got_element.tagName:

return False

if norm_child_text(want_element) != norm_child_text(got_element):

return False

if attrs_dict(want_element) != attrs_dict(got_element):

return False

want_children = children(want_element)

got_children = children(got_element)

if len(want_children) != len(got_children):

return False

return all(

check_element(want, got) for want, got in zip(want_children, got_children)

)

def first_node(document):

for node in document.childNodes:

if node.nodeType not in (

Node.COMMENT_NODE,

Node.DOCUMENT_TYPE_NODE,

Node.PROCESSING_INSTRUCTION_NODE,

):

return node

want = want.strip().replace("\\n", "\n")

got = got.strip().replace("\\n", "\n")

# If the string is not a complete xml document, we may need to add a

# root element. This allow us to compare fragments, like "<foo/><bar/>"

if not want.startswith("<?xml"):

wrapper = "<root>%s</root>"

want = wrapper % want

got = wrapper % got

# Parse the want and got strings, and compare the parsings.

want_root = first_node(parseString(want))

got_root = first_node(parseString(got))

return check_element(want_root, got_root)

class CaptureQueriesContext:

"""

Context manager that captures queries executed by the specified connection.

"""

def __init__(self, connection):

self.connection = connection

def __iter__(self):

return iter(self.captured_queries)

def __getitem__(self, index):

return self.captured_queries[index]

def __len__(self):

return len(self.captured_queries)

@property

def captured_queries(self):

return self.connection.queries[self.initial_queries : self.final_queries]

def __enter__(self):

self.force_debug_cursor = self.connection.force_debug_cursor

self.connection.force_debug_cursor = True

# Run any initialization queries if needed so that they won't be

# included as part of the count.

self.connection.ensure_connection()

self.initial_queries = len(self.connection.queries_log)

self.final_queries = None

request_started.disconnect(reset_queries)

return self

def __exit__(self, exc_type, exc_value, traceback):

self.connection.force_debug_cursor = self.force_debug_cursor

request_started.connect(reset_queries)

if exc_type is not None:

return

self.final_queries = len(self.connection.queries_log)

class ignore_warnings(TestContextDecorator):

def __init__(self, **kwargs):

self.ignore_kwargs = kwargs

if "message" in self.ignore_kwargs or "module" in self.ignore_kwargs:

self.filter_func = warnings.filterwarnings

else:

self.filter_func = warnings.simplefilter

super().__init__()

def enable(self):

self.catch_warnings = warnings.catch_warnings()

self.catch_warnings.__enter__()

self.filter_func("ignore", **self.ignore_kwargs)

def disable(self):

self.catch_warnings.__exit__(*sys.exc_info())

# On OSes that don't provide tzset (Windows), we can't set the timezone

# in which the program runs. As a consequence, we must skip tests that

# don't enforce a specific timezone (with timezone.override or equivalent),

# or attempt to interpret naive datetimes in the default timezone.

requires_tz_support = skipUnless(

TZ_SUPPORT,

"This test relies on the ability to run a program in an arbitrary "

"time zone, but your operating system isn't able to do that.",

)

@contextmanager

def extend_sys_path(*paths):

"""Context manager to temporarily add paths to sys.path."""

_orig_sys_path = sys.path[:]

sys.path.extend(paths)

try:

yield

finally:

sys.path = _orig_sys_path

@contextmanager

def isolate_lru_cache(lru_cache_object):

"""Clear the cache of an LRU cache object on entering and exiting."""

lru_cache_object.cache_clear()

try:

yield

finally:

lru_cache_object.cache_clear()

@contextmanager

def captured_output(stream_name):

"""Return a context manager used by captured_stdout/stdin/stderr

that temporarily replaces the sys stream *stream_name* with a StringIO.

Note: This function and the following ``captured_std*`` are copied

from CPython's ``test.support`` module."""

orig_stdout = getattr(sys, stream_name)

setattr(sys, stream_name, StringIO())

try:

yield getattr(sys, stream_name)

finally:

setattr(sys, stream_name, orig_stdout)

def captured_stdout():

"""Capture the output of sys.stdout:

with captured_stdout() as stdout:

print("hello")

self.assertEqual(stdout.getvalue(), "hello\n")

"""

return captured_output("stdout")

def captured_stderr():

"""Capture the output of sys.stderr:

with captured_stderr() as stderr:

print("hello", file=sys.stderr)

self.assertEqual(stderr.getvalue(), "hello\n")

"""

return captured_output("stderr")

def captured_stdin():

"""Capture the input to sys.stdin:

with captured_stdin() as stdin:

stdin.write('hello\n')

stdin.seek(0)

# call test code that consumes from sys.stdin

captured = input()

self.assertEqual(captured, "hello")

"""

return captured_output("stdin")

@contextmanager

def freeze_time(t):

"""

Context manager to temporarily freeze time.time(). This temporarily

modifies the time function of the time module. Modules which import the

time function directly (e.g. `from time import time`) won't be affected

This isn't meant as a public API, but helps reduce some repetitive code in

Django's test suite.

"""

_real_time = time.time

time.time = lambda: t

try:

yield

finally:

time.time = _real_time

def require_jinja2(test_func):

"""

Decorator to enable a Jinja2 template engine in addition to the regular

Django template engine for a test or skip it if Jinja2 isn't available.

"""

test_func = skipIf(jinja2 is None, "this test requires jinja2")(test_func)

return override_settings(

TEMPLATES=[

{

"BACKEND": "django.template.backends.django.DjangoTemplates",

"APP_DIRS": True,

},

{

"BACKEND": "django.template.backends.jinja2.Jinja2",

"APP_DIRS": True,

"OPTIONS": {"keep_trailing_newline": True},

},

]

)(test_func)

class override_script_prefix(TestContextDecorator):

"""Decorator or context manager to temporary override the script prefix."""

def __init__(self, prefix):

self.prefix = prefix

super().__init__()

def enable(self):

self.old_prefix = get_script_prefix()

set_script_prefix(self.prefix)

def disable(self):

set_script_prefix(self.old_prefix)

class LoggingCaptureMixin:

"""

Capture the output from the 'django' logger and store it on the class's

logger_output attribute.

"""

def setUp(self):

self.logger = logging.getLogger("django")

self.old_stream = self.logger.handlers[0].stream

self.logger_output = StringIO()

self.logger.handlers[0].stream = self.logger_output

def tearDown(self):

self.logger.handlers[0].stream = self.old_stream

class isolate_apps(TestContextDecorator):

"""

Act as either a decorator or a context manager to register models defined

in its wrapped context to an isolated registry.

The list of installed apps the isolated registry should contain must be

passed as arguments.

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.

"""

def __init__(self, *installed_apps, **kwargs):

self.installed_apps = installed_apps

super().__init__(**kwargs)

def enable(self):

self.old_apps = Options.default_apps

apps = Apps(self.installed_apps)

setattr(Options, "default_apps", apps)

return apps

def disable(self):

setattr(Options, "default_apps", self.old_apps)

class TimeKeeper:

def __init__(self):

self.records = collections.defaultdict(list)

@contextmanager

def timed(self, name):

self.records[name]

start_time = time.perf_counter()

try:

yield

finally:

end_time = time.perf_counter() - start_time

self.records[name].append(end_time)

def print_results(self):

for name, end_times in self.records.items():

for record_time in end_times:

record = "%s took %.3fs" % (name, record_time)

sys.stderr.write(record + os.linesep)

class NullTimeKeeper:

@contextmanager

def timed(self, name):

yield

def print_results(self):

pass

def tag(*tags):

"""Decorator to add tags to a test class or method."""

def decorator(obj):

if hasattr(obj, "tags"):

obj.tags = obj.tags.union(tags)

else:

setattr(obj, "tags", set(tags))

return obj

return decorator

@contextmanager

def register_lookup(field, *lookups, lookup_name=None):

"""

Context manager to temporarily register lookups on a model field using

lookup_name (or the lookup's lookup_name if not provided).

"""

try:

for lookup in lookups:

field.register_lookup(lookup, lookup_name)

yield

finally:

for lookup in lookups:

field._unregister_lookup(lookup, lookup_name)

def garbage_collect():

gc.collect()

if PYPY:

# Collecting weakreferences can take two collections on PyPy.

gc.collect()