Django 1.7.1运行测试时自定义字段失败

Question

我刚刚将django1.6.5项目升级到django1.7.1。我按照文档中记录的步骤从South迁移到django1.7.1，它工作得非常好。在

我遇到的问题是当我运行“python”时管理.py“在我的项目中，它失败了，错误是：

Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/commands/test.py", line 50, in run_from_argv
    super(Command, self).run_from_argv(argv)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/commands/test.py", line 71, in execute
    super(Command, self).execute(*args, **options)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/commands/test.py", line 88, in handle
    failures = test_runner.run_tests(test_labels)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/test/runner.py", line 147, in run_tests
    old_config = self.setup_databases()
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/test/runner.py", line 109, in setup_databases
    return setup_databases(self.verbosity, self.interactive, **kwargs)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/test/runner.py", line 299, in setup_databases
    serialize=connection.settings_dict.get("TEST", {}).get("SERIALIZE", True),
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/backends/creation.py", line 377, in create_test_db
    test_flush=True,
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 115, in call_command
    return klass.execute(*args, **defaults)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 160, in handle
    executor.migrate(targets, plan, fake=options.get("fake", False))
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 63, in migrate
    self.apply_migration(migration, fake=fake)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 97, in apply_migration
    migration.apply(project_state, schema_editor)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/migrations/migration.py", line 107, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/migrations/operations/models.py", line 36, in database_forwards
    schema_editor.create_model(model)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/backends/schema.py", line 209, in create_model
    definition, extra_params = self.column_sql(model, field)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/backends/schema.py", line 121, in column_sql
    default_value = self.effective_default(field)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/backends/schema.py", line 184, in effective_default
    default = field.get_db_prep_save(default, self.connection)
  File "/home/mark/.virtualenvs/clippy/local/lib/python2.7/site-packages/django/db/models/fields/__init__.py", line 627, in get_db_prep_save
    prepared=False)
  File "/home/mark/projects/clippy/core/fields.py", line 21, in get_db_prep_value
    return int(time.mktime(value.timetuple()))
AttributeError: 'NoneType' object has no attribute 'timetuple'

我相信这是因为我使用一个自定义字段将日期/时间字段作为时间戳整数存储在数据库中。代码是：

^{pr2}$

即使我从项目中删除所有单元测试，也会发生这种情况。有人知道是什么引起的吗？在升级到django1.7.1之前，它运行得很好。在

Answer 1

我在使用Django自定义字段时也有一些错误，我认为问题在于Django的迁移系统。在

尝试压缩/删除迁移（https://docs.djangoproject.com/en/1.7/topics/migrations/#squashing-migrations）

Answer 2

我通过在字段中的get_db_prep_value（）方法中添加以下内容来解决此问题：

if value is None:
    return value

因此，总字段变为：

^{pr2}$

这个问题现在解决了。在