测试Flask应用程序时如何处理导入:AssertionError:视图函数映射正在覆盖现有的端点函数

问题描述 投票:1回答:1

我正在努力了解如何在Flask中编写测试。

我已经继承了一个应用程序,它已经有一系列测试可以触及像/login这样的路径,并测试响应是否符合预期。

我的情况要复杂得多。我需要根据具体情况测试路由/方法,点击外部api,确定应用程序本身正在运行的容器中是否存在路径,启动一个需要10多分钟才能在不同机器上运行的进程 - - 各种各样的事情。所以我不能只是走上这条路,看看我是否得到了我想要的东西;我需要嘲笑和修补来模仿各种外部世界国家的影响。

现在我在brain_db/views.py中有一条如此定义的路线:

@app.route('/label_view/<int:scan_number>')
@login_required
def label_view(scan_number):
    <so much complicated logic>

在同一个文件brain_db/views.py中定义的第一个路由是

@app.route('/surface_test')
def surface_test():
    <some code>

这是抛出错误的文件的简化版本:

import unittest

from mock import MagicMock, patch
from flask_brain_db.test_helpers import set_up, tear_down
from flask_brain_db.brain_db.models import Scan
from brain_db.views import label_view

class BrainDBTest(unittest.TestCase):

    def setUp(self):
        app, db = set_up()

        scan = Scan(1, '000001', '000001_MR1', 'scan.nii.gz', scan_number=1)
        db.session.add(scan)
        scan = Scan.query.filter(Scan.scan_number == 1).first()
        db.session.commit()

    def tearDown(self):
        tear_down()

    def mock_volume_views_setup(self)

        scan = Scan.query.filter(Scan.scan_number == 1).first()
        container_file_path = '/path/to/file/in/container'
        return scan, container_file_path

    def mock_os_path_exists(self, arg):
        return True

    @patch('brain_db_helpers.volume_views_setup', mock_volume_views_setup)
    @patch('os.path.exists', mock_os_path_exists)
    def test_label_view(self):
        rv = label_view(1)
        assert(True) # I'll actually write tests when I figure out that I can!
        print rv

这是错误:

======================================================================
ERROR: brain_db.tests.test (unittest.loader.ModuleImportFailure)
----------------------------------------------------------------------
ImportError: Failed to import test module: brain_db.tests.test
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/unittest/loader.py", line 254, in _find_tests
    module = self._get_module_from_name(name)
  File "/usr/local/lib/python2.7/unittest/loader.py", line 232, in _get_module_from_name
    __import__(name)
  File "/usr/src/app/flask_brain_db/brain_db/tests/test.py", line 7, in <module>
    from brain_db.views import label_view
  File "/usr/src/app/flask_brain_db/brain_db/views.py", line 36, in <module>
    @app.route('/surface_test')
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1250, in decorator
    self.add_url_rule(rule, endpoint, f, **options)
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 66, in wrapper_func
    return f(self, *args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/flask/app.py", line 1221, in add_url_rule
    'existing endpoint function: %s' % endpoint)
AssertionError: View function mapping is overwriting an existing endpoint function: surface_test

我尝试解决我的问题所做的工作:我在SO上阅读了一些引用相同AssertionError的帖子。例如。 12。我可以看到问题的一般形状是我的路线已被定义,并且

from brain_db.views import label_view

再次执行views模块,从而重新定义路由,所以我得到一个错误。

我不明白的是我应该如何避免这种情况。我需要能够将方法导入另一个文件以便能够测试它。所有的路线都应该用if __name__ == main包裹吗?我是Flask开发的新手,还没有看到示例代码,在这种情况下;我怀疑这是正确的解决方案;当你试图搜索阻止代码在导入时被执行时,它就是唯一提供的东西。

我现在正在运行我的测试的方式是通过我的应用程序顶层的文件manage.py。它包含以下方法:

@manager.command
def test():
    """Runs the tests without coverage"""
    tests = unittest.TestLoader().discover(start_dir='.', pattern='test*.py')
    res = unittest.TextTestRunner(verbosity=2).run(tests)
    sys.exit(not res.wasSuccessful())

我在命令行运行python manage.py test

同样可能相关的是,虽然我在Brain_db中的子模块中进行了测试失败,但是在它之前运行了几个测试,这些测试在应用程序中定义的路径上运行并测试预期结果。但是,评论这些测试对我的测试失败的方式没有影响。

最后,我最初在from flask_brain_db.brain_db.models import Scan行遇到错误:

ERROR: brain_db.tests.test (unittest.loader.ModuleImportFailure)
----------------------------------------------------------------------
ImportError: Failed to import test module: brain_db.tests.test
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/unittest/loader.py", line 254, in _find_tests
    module = self._get_module_from_name(name)
  File "/usr/local/lib/python2.7/unittest/loader.py", line 232, in _get_module_from_name
    __import__(name)
  File "/usr/src/app/flask_brain_db/brain_db/tests/test.py", line 5, in <module>
    from flask_brain_db.brain_db.models import Scan
  File "/usr/src/app/flask_brain_db/brain_db/models.py", line 6, in <module>
    class Scan(db.Model):
  File "/usr/local/lib/python2.7/site-packages/flask_sqlalchemy/model.py", line 67, in __init__
    super(NameMetaMixin, cls).__init__(name, bases, d)
  File "/usr/local/lib/python2.7/site-packages/flask_sqlalchemy/model.py", line 121, in __init__
    super(BindMetaMixin, cls).__init__(name, bases, d)
  File "/usr/local/lib/python2.7/site-packages/sqlalchemy/ext/declarative/api.py", line 65, in __init__
    _as_declarative(cls, classname, cls.__dict__)
  File "/usr/local/lib/python2.7/site-packages/sqlalchemy/ext/declarative/base.py", line 116, in _as_declarative
    _MapperConfig.setup_mapping(cls, classname, dict_)
  File "/usr/local/lib/python2.7/site-packages/sqlalchemy/ext/declarative/base.py", line 144, in setup_mapping
    cfg_cls(cls_, classname, dict_)
  File "/usr/local/lib/python2.7/site-packages/sqlalchemy/ext/declarative/base.py", line 172, in __init__
    self._setup_table()
  File "/usr/local/lib/python2.7/site-packages/sqlalchemy/ext/declarative/base.py", line 465, in _setup_table
    **table_kw)
  File "/usr/local/lib/python2.7/site-packages/flask_sqlalchemy/model.py", line 90, in __table_cls__
    return sa.Table(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/sqlalchemy/sql/schema.py", line 439, in __new__
    "existing Table object." % key)
InvalidRequestError: Table 'scan' is already defined for this MetaData instance.  Specify 'extend_existing=True' to redefine options and columns on an existing Table object.

我通过包括让它消失了

__table_args__ = {'extend_existing': True}

在模型定义中,但我不知道我是否应该这样做,我怀疑我只是推迟了我现在遇到的同样问题。似乎根本问题是我不知道如何在不重新定义已经定义的一堆东西的情况下编写测试。

接近这个的正确方法是什么?如果我需要提供任何其他信息,请告诉我。

python unit-testing flask python-import
1个回答
0
投票

您应该能够从应用程序对象访问所有视图功能。尝试删除“来自brain_db.views import label_view”的行,然后使用以下命令运行set_up()后定义label_view方法:

label_view = app.view_functions [“label_view”]

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