添加 Wagtail 对象后 Django 测试开始失败

Question

我正在为我的 Django 模型使用常规 Django 测试，使用

./manage.py test non_wagtail_app_name

但突然之间（在添加了一些 Wagtail 模型之后），我无法运行它们：

Creating test database for alias 'default'...
Traceback (most recent call last):
  File "./manage.py", line 12, in <module>
    execute_from_command_line(sys.argv)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/__init__.py", line 356, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/commands/test.py", line 29, in run_from_argv
    super(Command, self).run_from_argv(argv)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/commands/test.py", line 62, in handle
    failures = test_runner.run_tests(test_labels)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/test/runner.py", line 601, in run_tests
    old_config = self.setup_databases()
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/test/runner.py", line 546, in setup_databases
    self.parallel, **kwargs
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/test/utils.py", line 187, in setup_databases
    serialize=connection.settings_dict.get('TEST', {}).get('SERIALIZE', True),
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/backends/base/creation.py", line 69, in create_test_db
    run_syncdb=True,
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/__init__.py", line 131, in call_command
    return command.execute(*args, **defaults)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/core/management/commands/migrate.py", line 204, in handle
    fake_initial=fake_initial,
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/migrations/executor.py", line 115, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/migrations/executor.py", line 145, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/migrations/executor.py", line 244, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/migrations/migration.py", line 129, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/migrations/operations/fields.py", line 88, in database_forwards
    field,
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 431, in add_field
    definition, params = self.column_sql(model, field, include_default=True)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 171, in column_sql
    default_value = self.effective_default(field)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/backends/base/schema.py", line 245, in effective_default
    default = field.get_db_prep_save(default, self.connection)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/models/fields/__init__.py", line 770, in get_db_prep_save
    prepared=False)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/django/db/models/fields/__init__.py", line 762, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/wagtail/core/fields.py", line 106, in get_prep_value
    return json.dumps(self.stream_block.get_prep_value(value), cls=DjangoJSONEncoder)
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/wagtail/core/blocks/stream_block.py", line 252, in get_prep_value
    for child in value  # child is a StreamChild instance
  File "/home/fleon/development/virmyasb/lib/python3.6/site-packages/wagtail/core/blocks/stream_block.py", line 252, in <listcomp>
    for child in value  # child is a StreamChild instance
AttributeError: 'str' object has no attribute 'block'

回溯似乎来自我项目的 Wagtail 部分（我的 Wagtail 模型使用 StreamFields 和 BlockFields），所以我似乎遗漏了一些东西（为我的 Wagtail 对象放置固定装置），但我不知道在哪里开始（我还没有设置 Wagtail 测试——是的，我知道，我应该）。我要测试的应用没有使用 Wagtail 的任何东西。

唯一有效的是 pg_dumping 我的 Postgres 数据库，在生成的文件中编辑数据库名称，将其导入 test_postgres 并将 -k 开关传递给 manage.py 测试，所以很明显我需要预填充 Wagtail 表。但是，在 Django 模型测试中使用固定装置并不能解决问题...

Answer 1

运行迁移失败。通过堆栈跟踪挖掘，我最好的猜测是：

这是一个将 StreamField 添加到现有页面模型的迁移，作为必需的 (null=False) 字段
该页面模型已有一个实例（很可能是主页，因为标准 Wagtail 项目模板会创建其中一个作为初始迁移的一部分），因此需要使用默认值填充它
您在创建迁移时指定的默认值是一个非空字符串，这不是 StreamField 的有效值

如果是这样，解决方法是编辑有问题的迁移并将 StreamField 上的 default 值更改为空字符串。

添加 Wagtail 对象后 Django 测试开始失败

Django tests have started failing after adding Wagtail objects

python

django

django-testing

wagtail