Django 1.11：在我的并行测试运行中“pickle”失败是什么？

Question

我使用的是 dockerized Django 1.11，现在想并行运行我长期存在的测试套件：

manage.py test mainfolder --parallel -v2

尽管它在我的测试套件中 2 分钟后失败（到目前为止所有运行测试都成功），并出现 pickle 错误。然而，堆栈跟踪并没有告诉我它发生在哪里。我怎样才能更接近失败的地方呢？ tblib已安装。

test_foo (myapp.some.testmodule.SomeTestCase) ... ok
Traceback (most recent call last):
  File "./myapp/manage.py", line 34, in <module>
    execute_from_command_line()
  File "/var/venv-stable/lib/python2.7/site-packages/django/core/management/__init__.py", line 364, in execute_from_command_line
    utility.execute()
  File "/var/venv-stable/lib/python2.7/site-packages/django/core/management/__init__.py", line 356, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/var/venv-stable/lib/python2.7/site-packages/django/core/management/commands/test.py", line 29, in run_from_argv
    super(Command, self).run_from_argv(argv)
  File "/var/venv-stable/lib/python2.7/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/var/venv-stable/lib/python2.7/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "/var/venv-stable/lib/python2.7/site-packages/django/core/management/commands/test.py", line 62, in handle
    failures = test_runner.run_tests(test_labels)
  File "/var/venv-stable/lib/python2.7/site-packages/django/test/runner.py", line 603, in run_tests
    result = self.run_suite(suite)
  File "/var/venv-stable/lib/python2.7/site-packages/django/test/runner.py", line 567, in run_suite
    return runner.run(suite)
  File "/usr/lib/python2.7/unittest/runner.py", line 151, in run
    test(result)
  File "/usr/lib/python2.7/unittest/suite.py", line 70, in __call__
    return self.run(*args, **kwds)
  File "/var/venv-stable/lib/python2.7/site-packages/django/test/runner.py", line 370, in run
    subsuite_index, events = test_results.next(timeout=0.1)
  File "/usr/lib/python2.7/multiprocessing/pool.py", line 659, in next
    raise value
cPickle.PicklingError: Can't pickle <type 'module'>: attribute lookup __builtin__.module failed

Answer 1

在内心深处，我有一个__init__方法混合到测试用例中，而不是我编写的。它将对导入模块的引用存储到类中，我不知道这对谁有意义。

from django.core import mail

def __init__(self, *args, **kwargs):
    super(EmailTestHelperMixin, self).__init__(*args, **kwargs)
    self.mail = mail

删除它解决了我的问题。