多数据库和非托管模型 - 测试用例失败
Posted
技术标签:
【中文标题】多数据库和非托管模型 - 测试用例失败【英文标题】：Multi db and unmanged models - Test case are failing 【发布时间】：2020-01-29 22:50:42 【问题描述】：我使用非托管（只读）模型设置了 mutlidb。这些模型没有迁移。我试图测试 view.py 的功能。在 sqlite3 数据库中，测试表的这些模式不会导致导致测试用例失败的问题。 在 view.py 中，我导入的非托管（只读）模型失败了。
我已经点击链接进行测试Testing against unmanaged models
提到了多数据库设置
test_runner.py
from django.test.runner import DiscoverRunner
class DisableMigrations(object):
def __contains__(self, item):
return True
def __getitem__(self, item):
return None
class UnManagedModelTestRunner(DiscoverRunner):
def setup_test_environment(self, *args, **kwargs):
from django.apps import apps
# app_name = apps.get_app_config('core_esp')
self.unmanaged_models = [m for m in apps.get_models() if not m._meta.managed and m._meta.app_label is 'core_esp']
for m in self.unmanaged_models:
m._meta.managed = True
super(UnManagedModelTestRunner, self).setup_test_environment(*args, **kwargs)
def teardown_test_environment(self, *args, **kwargs):
super(UnManagedModelTestRunner, self).teardown_test_environment(*args, **kwargs)
# reset un managed models
for m in self.unmanaged_models:
m._meta.managed = False
settings.py
if 'test' in sys.argv or 'test_coverage' in sys.argv:
DATABASES =
'default':
'ENGINE': 'django.db.backends.sqlite3',
'NAME': 'db.sqlite3',
,
'test_db':
'ENGINE': 'django.db.backends.sqlite3',
'NAME': 'db.sqlite3',
INSTALLED_APPS = ['test']
# Skip the migrations by setting "MIGRATION_MODULES"
# to the DisableMigrations class defined above
#
MIGRATION_MODULES = DisableMigrations()
# Set Django's test runner to the custom class defined above
TEST_RUNNER = 'apps.settings.test_runner.UnManagedModelTestRunner'
DATABASE_ROUTERS = ('apps.tests.test_dbrouter.TestApiRouter', )
models.py
from django.db import models
class TestModelA(models.Model):
testid = models.CharField(max_length=200)
class Meta:
managed = False
db_table = 'TestD'
class TestModelB(models.Model):
testid = models.CharField(max_length=200)
class Meta:
managed = False
db_table = 'test_model_b'
app_label = 'application_b'
test.py
class MyTestCase(TestCase):
def test_my_function(self):
# view is called
# serializer called with read only model
pass
错误
Traceback (most recent call last):
File "C:\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "C:\lib\site-packages\django\db\backends\sqlite3\base.py", line 383, in execute return Database.Cursor.execute(self, query, params)
sqlite3.OperationalError: no such table: TestD
The above exception was the direct cause of the following exception: Traceback (most recent call last):
File "manage.py", line 21, in <module> main()
File "manage.py", line 17, in main execute_from_command_line(sys.argv)
File "C:\lib\site-packages\django\core\management\__init__.py", line 381, in execute_from_command_line utility.execute()
File "C:\lib\site-packages\django\core\management\__init__.py", line 375, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\lib\site-packages\django\core\management\commands\test.py", line 23, in run_from_argv
super().run_from_argv(argv)
File "C:\lib\site-packages\django\core\management\base.py", line 323, in run_from_argv
self.execute(*args, **cmd_options)
File "C:\lib\site-packages\django\core\management\base.py", line execute
output = self.handle(*args, **options)
File "C:\lib\site-packages\django\core\management\commands\test.py", line 53, in handle failures = test_runner.run_tests(test_labels)
File "C:\lib\site-packages\django\test\runner.py", line 627, in run_tests
suite = self.build_suite(test_labels, extra_tests)
File "C:\lib\site-packages\django\test\runner.py", line 488, in build_suites
tests = self.test_loader.loadTestsFromName(label)
File "c:\program files\python37\Lib\unittest\loader.py", line 154, in loadTestsFromName
module = __import__(module_name)
File "C:\tests\tests.py", line 5, in <module>
from .views import (
File "C:\views.py", line 6, in <module>
from .serializers import (
File "C:\serializers.py", line 9, in <module>
class TestSerializer(serializers.Serializer):
File "C:\serializers.py", line 13, in TestSerializer
required=False, style='base_template': 'select_multiple.html'
File "C:\lib\site-packages\rest_framework\fields.py", line 1476, in __init__
super(MultipleChoiceField, self).__init__(*args, **kwargs)
File "C:\lib\site-packages\rest_framework\fields.py", line 1417, in __init__
self.choices = choices
File "C:\lib\site-packages\rest_framework\fields.py", line 1453, in _set_choices
for row in compiler.results_iter(chunked_fetch=self.chunked_fetch, chunk_size=self.chunk_size):
File "C:\lib\site-packages\django\db\models\sql\compiler.py", line 1052, in results_iter
results = self.execute_sql(MULTI, chunked_fetch=chunked_fetch, chunk_size=chunk_size)
File "C:\lib\site-packages\django\db\models\sql\compiler.py", line 1100, in execute_sql
cursor.execute(sql, params)
File "C:\lib\site-packages\django\db\backends\utils.py", line 67, in execute
return self._execute_with_wrappers(sql, params, many=False,
executor=self._execute)
File "C:\lib\site-packages\django\db\backends\utils.py", line 76, in
_execute_with_wrappers
return executor(sql, params, many, context)
File "C:\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "C:\lib\site-packages\django\db\utils.py", line 89, in __exit__
raise dj_exc_value.with_traceback(traceback) from exc_value
File "C:\lib\site-packages\django\db\backends\utils.py", line 84, in _execute
return self.cursor.execute(sql, params)
File "C:\lib\site-packages\django\db\backends\sqlite3\base.py", line 383, in execute
return Database.Cursor.execute(self, query, params)
django.db.utils.OperationalError: no such table: TESTD
【问题讨论】：
How to create table during Django tests with managed = False的可能重复 【参考方案1】：我可以告诉你我是如何解决这个问题的；
所以我创建了一个信号，它或多或少看起来像这样：
def create_test_models(**kwargs):
if "test" in sys.argv:
Organization = apps.get_model("organizations.Organization")
... # other models here too
# as we do not manage it - we need to create it manually;
with connection.schema_editor() as schema_editor:
sid = transaction.savepoint()
try:
schema_editor.create_model(Organization)
... # different models here if needed
transaction.savepoint_commit(sid)
except ProgrammingError: # tables already exists;
transaction.savepoint_rollback(sid)
此信号在配置中连接为pre_migrate 信号：
class OrganizationsConfig(AppConfig):
name = "engine.organizations"
def ready(self):
# run after each migration; so each deploy, but this method can handle the
# incremental updates.
pre_migrate.connect(create_test_models, sender=self)
这可能不是超级解决方案 - 但它正在运行，并且您在测试期间创建了模型，您可以使用它们或创建测试数据等。
希望这将帮助您继续前进。
【讨论】：
@MichelSamia 任何堆栈跟踪？ 哎呀抱歉，我没有完全实现它，我只是在setUp中直接尝试了模式编辑器。我想删除我的反对票，但在您编辑答案之前我不允许这样做。【参考方案2】：我在当前的 django 2.2 中找到了一个很好的解决方案。与 pytest-django 完美配合，但即使没有 pytest 也可能工作。
要使其正常工作，您需要：
将您的项目拆分为两个 django 应用程序。一个将仅包含非托管模型，另一个将包含其余模型。不要在这两个应用中指定 managed = False
在 DATABASES 的 settings.py 中，您将拥有两个数据库，一个是默认数据库，一个是您的外部数据库
在您有设置的同一文件夹中，创建 routers.py 并实现一个路由器，该路由器将根据应用标签路由到给定的 DB（cca 45 行，包括您永远不会写入这些外部 DB 的检查）。然后将此路由器添加到 settings.py 的 ROUTERS 列表中。当使用 pytest 运行测试时，它确实会为没有迁移文件夹的应用创建所有表
【讨论】：
我会尽量简化它，并将路由器放在这里。可能当使用 managed = False 时，路由器会更简单 即使没有路由器，你也可以使用它，但它会在默认测试数据库中创建非托管模型。这与实际环境中有些不同，例如外键可以在这两者之间进行。以上是关于多数据库和非托管模型 - 测试用例失败的主要内容，如果未能解决你的问题，请参考以下文章