Django 测试抱怨缺少表

Question

当我对 Customer 模型进行测试时，我收到以下错误：

DatabaseError: (1146, "Table 'test_mcif2.customer' doesn't exist")

我并不完全感到惊讶，因为我的 Django 项目已连接到“旧版”数据库。由于我的表不是“以 Django 方式”创建的，因此 Django 无法与它们交谈并不令人震惊。这是我的模型：

from django.db import models
from django.db import connection, transaction
from mcif.models.mcif_model import McifModel

class Customer(McifModel):

    class Meta:
        db_table = u'customer'
        app_name = 'mcif'

    id = models.BigIntegerField(primary_key=True)
    customer_number = models.CharField(unique=True, max_length=255)
    social_security_number = models.CharField(unique=True, max_length=33)
    name = models.CharField(unique=True, max_length=255)
    phone = models.CharField(unique=True, max_length=255)
    deceased = models.IntegerField(unique=True, null=True, blank=True)
    do_not_mail = models.IntegerField(null=True, blank=True)
    created_at = models.DateTimeField()
    updated_at = models.DateTimeField()

    def distinguishing_column_names(self):
        return ['name', 'customer_number', 'social_security_number', 'phone']

知道为什么这不起作用吗？

编辑：这里是McifModel：

from django.db import models
from django.db import connection, transaction

class McifModel(models.Model):
    class Meta:
        abstract = True

    def upsert(self):
        cursor = connection.cursor()
        cursor.execute(self.upsert_sql())
        transaction.commit_unless_managed()
        return self

    def value_list(self):
        return ','.join(map(lambda column_name: "'{c}'".format(c=getattr(self, column_name)), self.distinguishing_column_names()))

    def upsert_sql(self):
        column_names = ','.join(self.distinguishing_column_names())
        return "INSERT IGNORE INTO {t} ({c}) VALUES ({v})".format(t=self._meta.db_table, c=column_names, v=self.value_list())

    @classmethod
    def save_from_row(cls, row):
        object = cls()
        map(lambda column_name: setattr(object, column_name, row.value(object._meta.db_table, column_name)), object.distinguishing_column_names())
        return object.upsert()

编辑：我接受了 tarequeh 的建议，并将 Caktus 文件的内容放入 mcif/utils.py。我还设置了TEST_RUNNER = 'mcif.utils.ManagedModelTestRunner'。如果我进入控制台，我可以验证 Customer 是不受管理的：

>>> [m for m in get_models() if not m._meta.managed]
[<class 'mcif.models.customer.Customer'>]

但是，我的测试仍然抱怨该表不存在。我错过了什么？

这是我的 settings.py：

# Django settings for mcifdjango project.

DEBUG = True
TEMPLATE_DEBUG = DEBUG

ADMINS = (
    ('Jason Swett', 'jason.swett@gmail.com'),
)

MANAGERS = ADMINS

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.
        'NAME': 'xxxxx',                # Or path to database file if using sqlite3.
        'USER': 'xxxxx',                       # Not used with sqlite3.
        'PASSWORD': 'xxxxx',           # Not used with sqlite3.
        'HOST': '',                           # Set to empty string for localhost. Not used with sqlite3.
        'PORT': '',                           # Set to empty string for default. Not used with sqlite3.
    }
}

# Local time zone for this installation. Choices can be found here:
# http://en.wikipedia.org/wiki/List_of_tz_zones_by_name
# although not all choices may be available on all operating systems.
# On Unix systems, a value of None will cause Django to use the same
# timezone as the operating system.
# If running in a Windows environment this must be set to the same as your
# system time zone.
TIME_ZONE = 'America/Chicago'

# Language code for this installation. All choices can be found here:
# http://www.i18nguy.com/unicode/language-identifiers.html
LANGUAGE_CODE = 'en-us'

SITE_ID = 1

# If you set this to False, Django will make some optimizations so as not
# to load the internationalization machinery.
USE_I18N = True

# If you set this to False, Django will not format dates, numbers and
# calendars according to the current locale
USE_L10N = True

# Absolute path to the directory that holds media.
# Example: "/home/media/media.lawrence.com/"
MEDIA_ROOT = ''

# URL that handles the media served from MEDIA_ROOT. Make sure to use a
# trailing slash if there is a path component (optional in other cases).
# Examples: "http://media.lawrence.com", "http://example.com/media/"
MEDIA_URL = ''

# URL prefix for admin media -- CSS, JavaScript and images. Make sure to use a
# trailing slash.
# Examples: "http://foo.com/media/", "/media/".
ADMIN_MEDIA_PREFIX = '/media/'

# Make this unique, and don't share it with anybody.
SECRET_KEY = '#7+qm%hqfe+z8ul5@x_i&sqmu!n=4sa0&i0_#)m99*w$fbk3%#'

# List of callables that know how to import templates from various sources.
TEMPLATE_LOADERS = (
    'django.template.loaders.filesystem.Loader',
    'django.template.loaders.app_directories.Loader',
#     'django.template.loaders.eggs.Loader',
)

MIDDLEWARE_CLASSES = (
    'django.middleware.common.CommonMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
)

ROOT_URLCONF = 'mcifdjango.urls'

TEMPLATE_DIRS = (
    # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates".
    # Always use forward slashes, even on Windows.
    # Don't forget to use absolute paths, not relative paths.
)

INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.messages',
    'django.contrib.admin',
    'django_extensions',
    'mcif',
    # Uncomment the next line to enable the admin:
    # 'django.contrib.admin',
    # Uncomment the next line to enable admin documentation:
    # 'django.contrib.admindocs',
)

TEST_RUNNER = 'mcif.utils.ManagedModelTestRunner'

import os
ROOTDIR = os.path.abspath(os.path.dirname(__file__))
TEMPLATE_DIRS = (
    # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates".
    # Always use forward slashes, even on Windows.
    # Don't forget to use absolute paths, not relative paths.
    ROOTDIR + '/mcif/templates',
)

编辑 2：

这是我现在的Customer 课程：

from django.db import models
from django.db import connection, transaction
from mcif.models.mcif_model import McifModel

class Customer(McifModel):

    class Meta:
        db_table = u'customer'
        managed = False

    id = models.BigIntegerField(primary_key=True)
    customer_number = models.CharField(unique=True, max_length=255)
    social_security_number = models.CharField(unique=True, max_length=33)
    name = models.CharField(unique=True, max_length=255)
    phone = models.CharField(unique=True, max_length=255)
    deceased = models.IntegerField(unique=True, null=True, blank=True)
    do_not_mail = models.IntegerField(null=True, blank=True)
    created_at = models.DateTimeField()
    updated_at = models.DateTimeField()

    def distinguishing_column_names(self):
        return ['name', 'customer_number', 'social_security_number', 'phone']

这是我运行测试时得到的结果：

$ ./manage.py test mcif.CustomerUpsertTest
Creating test database 'default'...
Creating table auth_permission
Creating table auth_group_permissions
Creating table auth_group
Creating table auth_user_user_permissions
Creating table auth_user_groups
Creating table auth_user
Creating table auth_message
Creating table django_content_type
Creating table django_session
Creating table django_site
Creating table django_admin_log
Installing index for auth.Permission model
Installing index for auth.Group_permissions model
Installing index for auth.User_user_permissions model
Installing index for auth.User_groups model
Installing index for auth.Message model
Installing index for admin.LogEntry model
No fixtures found.
E
======================================================================
ERROR: test_upsert (mcif.tests.customer_upsert_test.CustomerUpsertTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jason/projects/mcifdjango/mcif/tests/customer_upsert_test.py", line 9, in test_upsert
    customer.upsert()
  File "/home/jason/projects/mcifdjango/mcif/models/mcif_model.py", line 11, in upsert
    cursor.execute(self.upsert_sql())
  File "/usr/lib/pymodules/python2.6/django/db/backends/mysql/base.py", line 86, in execute
    return self.cursor.execute(query, args)
  File "/usr/lib/pymodules/python2.6/MySQLdb/cursors.py", line 166, in execute
    self.errorhandler(self, exc, value)
  File "/usr/lib/pymodules/python2.6/MySQLdb/connections.py", line 35, in defaulterrorhandler
    raise errorclass, errorvalue
DatabaseError: (1146, "Table 'test_mcif_django.customer' doesn't exist")

----------------------------------------------------------------------
Ran 1 test in 3.724s

FAILED (errors=1)
Destroying test database 'default'...

Answer 1

这是一个更新的解决方案，它也适用于当前版本的 Django（我在 Django 3.2.11 上对其进行了测试）： https://medium.com/an-idea/testing-with-the-legacy-database-in-django-3be84786daba

此外，如果您想进一步使用旧数据库的数据填充 Django 测试数据库： Check out fixtures

Answer 2

tarequeh 提出的解决方案在覆盖 DATABASE_ROUTERS 后对我有用。

我正在使用路由器来防止对遗留数据库的写入。为了解决这个问题，我创建了一个包含以下内容的 test_settings 文件：

from settings import *

DEBUG = True

TEST_RUNNER = 'legacy.utils.ManagedModelTestRunner'

DATABASE_ROUTERS = []

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.sqlite3',
        'NAME': os.path.join(HERE, 'test.db'),
    },
}

然后在运行测试时：

python manage.py test [app_name] --settings=test_settings

Answer 3

由于您使用的是旧数据库，因此您可能没有将应用名称添加到 INSTALLED_APPS。如果应用程序未包含在 INSTALLED_APPS 中，则不会在 syncdb 上创建应用程序模型的表。这适用于您的生产环境，因为您已经有一个表，但在测试环境中却没有。

您可以采用以下任何一种：

• supermonkeypatch 方式：从 Customer 类 Meta 中取出 app_name，将模型放在 python 模块名称 mcif 内的 models.py 文件中，并将 mcif 添加到 INSTALLED_APPS - 只是为了测试

• 更好的方法：扩展 DjangoTestSuiteRunner 并覆盖 setup_test_environment 以调用 super，然后在测试数据库中手动创建旧表。

• 最好的方法：将模型放入正确命名的应用模块中。从模型 Meta 中删除 app_name 但添加 managed=False docs。在 INSTALLED_APPS 中包含应用名称。现在 django 不会为该模型创建表。然后使用这个nice snippet Caktus 小组的人们编译来运行你的测试。

干杯！

编辑 - 如何使用被覆盖的 DjangoTestSuiteRunner

为此，您至少需要 Django 1.2。

从here 复制代码。将其放在 mcif 应用内的 utils.py 中。

在 settings.py 中添加/编辑以下内容：

TEST_RUNNER = 'mcif.utils.ManagedModelTestRunner'

现在，当您运行测试时，所有非托管表将仅在测试期间被视为托管表。因此，这些表将在运行测试之前创建。

注意这部分代码，这就是魔法发生的地方。

self.unmanaged_models = [m for m in get_models() if not m._meta.managed]
for m in self.unmanaged_models:
    m._meta.managed = True

第二次编辑：可能的陷阱

确保以下几点：

• DB 用户有权创建数据库而不仅仅是表，因为 django 将尝试创建测试数据库
• 测试用例扩展了 django.test.TransactionTestCase，因为您有事务行为
• 如果以上都不适用，请在 ManagedModelTestRunner 的 setup_test_environment 中放置一个 pdb，以确保可以访问代码。因为如果达到该代码，则应创建表

第三次修改：调试 在 mcif.utils.ManagedModelTestRunner 内部，将 setup_test_environment 函数替换为以下内容，并让我知道您的测试输出是否发生变化：

def setup_test_environment(self, *args, **kwargs):
    print "Loading ManagedModelTestRunner"
    from django.db.models.loading import get_models
    self.unmanaged_models = [m for m in get_models()
                             if not m._meta.managed]
    for m in self.unmanaged_models:
        print "Modifying model %s to be managed for testing" % m
        m._meta.managed = True
    super(ManagedModelTestRunner, self).setup_test_environment(*args, **kwargs)

Answer 4

以上信息不足以回答您的第一个问题。然而，一旦你解决了这个问题，你可能会因为以下原因想要安装django-extensions：它有一个非常有用的sqldiff 命令，如果遗留数据库和你的应用程序模型不匹配，它将通知你。