Django Unittest: Typeerror: 'NoneType' Objekt ist nicht iterable

Question

python3 manage.py Test apps.favorites

Traceback (most recent call last): 
    File "manage.py", line 10, in <module> 
    execute_from_command_line(sys.argv) 
    File "/home/dmitry/.pyenv/versions/p/lib/python3.5/site-packages/django/core/management/__init__.py", line 367, in execute_e 
    utility.execute() 
    File "/home/dmitry/.pyenv/versions/p/lib/python3.5/site-packages/django/core/management/__init__.py", line 359, in execute 
    self.fetch_command(subcommand).run_from_argv(self.argv) 
    File "/home/dmitry/.pyenv/versions/p/lib/python3.5/site-packages/django/core/management/commands/test.py", line 29, in run_v 
    super(Command, self).run_from_argv(argv) 
    File "/home/dmitry/.pyenv/versions/p/lib/python3.5/site-packages/django/core/management/base.py", line 294, in run_from_argv 
    self.execute(*args, **cmd_options) 
    File "/home/dmitry/.pyenv/versions/p/lib/python3.5/site-packages/django/core/management/base.py", line 345, in execute 
    output = self.handle(*args, **options) 
    File "/home/dmitry/.pyenv/versions/p/lib/python3.5/site-packages/django/core/management/commands/test.py", line 72, in hande 
    failures = test_runner.run_tests(test_labels) 
    File "/home/dmitry/.pyenv/versions/p/lib/python3.5/site-packages/django/test/runner.py", line 548, in run_tests 
    suite = self.build_suite(test_labels, extra_tests) 
    File "/home/dmitry/.pyenv/versions/p/lib/python3.5/site-packages/django/test/runner.py", line 466, in build_suite 
    tests = self.test_loader.discover(start_dir=label, **kwargs) 
    File "/home/dmitry/.pyenv/versions/3.5.1/lib/python3.5/unittest/loader.py", line 341, in discover 
    tests = list(self._find_tests(start_dir, pattern)) 
    File "/home/dmitry/.pyenv/versions/3.5.1/lib/python3.5/unittest/loader.py", line 406, in _find_tests 
    yield from self._find_tests(full_path, pattern, namespace) 
    File "/home/dmitry/.pyenv/versions/3.5.1/lib/python3.5/unittest/loader.py", line 398, in _find_tests 
    full_path, pattern, namespace) 
TypeError: 'NoneType' object is not iterable 

Sehr kryptische Nachricht ohne Details. Alles hat letzte Nacht funktioniert.

apps/favorites 
├── admin.py 
├── api 
│   ├── __init__.py 
│   ├── mixins.py 
│   ├── permissions.py 
│   └── __pycache__ 
│    ├── __init__.cpython-35.pyc 
│    ├── mixins.cpython-35.pyc 
│    └── permissions.cpython-35.pyc 
├── apps.py 
├── __init__.py 
├── managers.py 
├── migrations 
│   ├── 0001_initial.py 
│   ├── __init__.py 
│   └── __pycache__ 
│    ├── 0001_initial.cpython-35.pyc 
│    └── __init__.cpython-35.pyc 
├── models.py 
├── __pycache__ 
│   ├── admin.cpython-35.pyc 
│   ├── apps.cpython-35.pyc 
│   ├── __init__.cpython-35.pyc 
│   ├── managers.cpython-35.pyc 
│   └── models.cpython-35.pyc 
└── tests 
    ├── __init__.py 
    ├── __pycache__ 
    │   ├── __init__.cpython-35.pyc 
    │   └── test_models.cpython-35.pyc 
    └── test_models.py 

7 directories, 24 files 

Answer 1

Dies geschieht in der Regel, wenn Sie eine Liste (oder eine andere Sequenz) erwarten von einer Funktion zurückgegeben, sondern ein leeres Ergebnis von None bekommen. Wenn Sie dann diese vermeintliche Liste einer Iteration zuweisen, z. B. einer einfachen for-Schleife, wird der Fehler angezeigt. Zum Beispiel:

>>> oops = None 
>>> for i in oops: 
...  print i 
... 
Traceback (most recent call last): 
    File "<stdin>", line 1, in <module> 
TypeError: 'NoneType' object is not iterable