python - 使用flask对请求中的嵌套对象进行单元测试

一个单元如何测试用flask编写的REST API端点，该端点接受请求主体的嵌套字典对象？

这是一个使用flask和webargs进行输入验证的示例，

from flask import Flask
from webargs import fields
from webargs.flaskparser import use_args

app = Flask(__name__)

hello_args = {
    'a': fields.Nested({'name' : fields.Str()})
}

@app.route('/', methods=['POST'])
@use_args(hello_args)
def index(args):
    return 'Hello ' + str(args)


def test_app():
    app.config['TESTING'] = True
    test_app = app.test_client(use_cookies=False)
    test_app.post(data={"a": {"name": "Alice"}})


if __name__ == '__main__':
    app.run()

直接使用此enpoint时可以正常工作，

% curl -H "Content-Type: application/json" -X POST \
       -d '{"a":{"name": "Alice"}}' http://localhost:5000

Hello {'a': {'name': 'Alice'}}%

但是在单元测试内部调用werkzeug.test.EnvironBuilder时会引发异常，

nosetests /tmp/test.py
E
======================================================================
ERROR: test.test_app
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/usr/lib64/python3.4/site-packages/nose/case.py", line 198, in runTest
    self.test(*self.arg)
  File "/tmp/test.py", line 26, in test_app
    test_app.post(data={"a": {"name": "Alice"}})
  File "/home/rth/.local/lib64/python3.4/site-packages/werkzeug/test.py", line 788, in post
    return self.open(*args, **kw)
  File "/home/rth/.local/lib64/python3.4/site-packages/flask/testing.py", line 103, in open
    builder = make_test_environ_builder(self.application, *args, **kwargs)
  File "/home/rth/.local/lib64/python3.4/site-packages/flask/testing.py", line 34, in make_test_environ_builder
    return EnvironBuilder(path, base_url, *args, **kwargs)
  File "/home/rth/.local/lib64/python3.4/site-packages/werkzeug/test.py", line 338, in __init__
    self._add_file_from_data(key, value)
  File "/home/rth/.local/lib64/python3.4/site-packages/werkzeug/test.py", line 355, in _add_file_from_data
    self.files.add_file(key, **value)
TypeError: add_file() got multiple values for argument 'name'

----------------------------------------------------------------------
Ran 1 test in 0.011s

FAILED (errors=1)

它使用Python 3.5，flask 0.12和webargs 1.5.2。

还通过https://github.com/pallets/flask/issues/2176提交了问题

最佳答案

看来，尽管使用了webargs，输入数据仍必须进行序列化并显式指定content_type，这样才能起作用。特别是替换

test_app.post(data={"a": {"name": "Alice"}})

与

test_app.post(data=json.dumps({"a": {"name": "Alice"}}),
            content_type='application/json')

解决了此问题（另请参见相关的SO解答here）。