I am trying to create mock object for unit testing but somehow always actual object is called.
Below is the code for reference:-
utility_functions.py
import os
import json
def get_module_configurations(key):
config = os.getcwd()
config = config + "\\xyz.json"
with open(config) as f:
module_config = json.load(f)
module_config = module_config[key]
return module_config
load_class
from importlib import import_module
from inspect import isclass, isabstract
def load_module(data):
package_path = data['Package']
module_name = data['ModuleName']
class_name = data['ClassName']
try:
module_name = str(module_name.split('.py')[0])
module = import_module('.' + module_name, package_path)
except Exception as error:
pass
try:
_class = getattr(module, class_name)
except Exception as error:
pass
if isclass(_class) and not (isabstract(_class)):
return _class
else:
return None
function1.py
import load_class
from utility_functions import get_module_configurations
def load_helpers(task_name):
module = get_module_configurations(task_name)
cls = load_class.load_module(module)
return cls
test_function.py
import pytest
from function1 import load_helpers
def test_mock(mocker):
class_to_load = {"Package": "Test", "ModuleName": "default_class.py", "ClassName":
"DefaultClass"}
mocker.patch('function1.load_helpers', return_value= class_to_load)
result = load_helpers('c')
assert result is not None
Since I am mocking, load helpers should not be called but it always calls actual implementation saying path is invalid.
I am missing something basic but cannot figure out what.
Any help will be great.
If you are importing the function into your module (from function1 import load_helpers), you need to patch it as if it was part of it. This means that instead of...
mocker.patch('function1.load_helpers', return_value=class_to_load)
...you should use...
mocker.patch('test_function.load_helpers', return_value=class_to_load)
PS: I assume that you are just practicing mocking because otherwise your test function doesn't make sense.
Related
From this, I was able to make this:
import os
import types
import zipfile
import sys
import io
class ZipImporter(object):
def __init__(self, zip_file):
self.zfile = zip_file
self._paths = [x.filename for x in self.zfile.filelist]
def _mod_to_paths(self, fullname):
# get the python module name
py_filename = fullname.replace(".", os.sep) + ".py"
# get the filename if it is a package/subpackage
py_package = fullname.replace(".", os.sep) + "/__init__.py"
print(py_package)
if py_filename in self._paths:
return py_filename
elif py_package in self._paths:
return py_package
else:
return None
def find_module(self, fullname, path):
if self._mod_to_paths(fullname) is not None:
return self
return None
def load_module(self, fullname):
filename = self._mod_to_paths(fullname)
if not filename in self._paths:
raise ImportError(fullname)
new_module = types.ModuleType(fullname)
new_module.__name__=fullname
print(fullname)
exec(self.zfile.open(filename, 'r').read(),new_module.__dict__)
new_module.__file__ = filename
new_module.__loader__ = self
if filename.endswith("__init__.py"):
new_module.__path__ = []
new_module.__package__ = fullname
else:
new_module.__package__ = fullname.rpartition('.')[0]
sys.modules[fullname]=new_module
return new_module
module_zip=zipfile.ZipFile(io.BytesIO(),"w")
for key in module_dict:
module_zip.writestr(key,module_dict[key])
sys.meta_path.append(ZipImporter(module_zip))
import pyparsing
Using the source code of pyparsing as a test. However, it fails with ImportError: attempted relative import with no known parent package. Even if I replace all the relative imports with absolute imports, it fails with RecursionError: maximum recursion depth exceeded while calling a Python object, as it tries to import pyparsing repeatedly. Is there something fundamental I'm not understanding about the way Python's import system works?
I found the answer --- PEP 302 says that:
Note that the module object must be in sys.modules before the loader executes the module code. This is crucial because the module code may (directly or indirectly) import itself; adding it to sys.modules beforehand prevents unbounded recursion in the worst case and multiple loading in the best.
I'm refactoring some code and have moved around some files. But for backwards compatibility, I would like to make all of my modules keep their old import paths.
my file structure is as follows
--| calcs/
----| __init__.py
----| new_dir
------| new_file1.py
------| new_file2.py
What do I need to do ensure that I can use an import like
import calcs.newfile1.foo
# OR
from calcs.newfile1 import foo
I have tried a few methods of adding the imports to the top level __init__.py file. As is reccommended here
But while this seems to allow an import such as import calcs.newfile1, An import such as import calcs.newfile1.foo raises ModuleNotFoundError: No module named calcs.newfile1
I expect that I need python to recognize calcs.newfile1 as a **module **. At the moment it seems to just be importing it as a class or other object of some sort
The only way i know how to do it is by creating a custom import hook.
Here is the PEP for more information.
If you need some help on how to implement one, i'll suggest you to take a look at the six module,
here
and here
Basically your calcs/__init__.py will become like this:
''' calcs/__init__.py '''
from .new_dir import new_file1, new_file2
import sys
__path__ = []
__package__ = __name__
class CalcsImporter:
def __init__(self, exported_mods):
self.exported_mods = {
f'{__name__}.{key}': value for key, value in exported_mods.items()
}
def find_module(self, fullname, path=None):
if fullname in self.exported_mods:
return self
return None
def load_module(self, fullname):
try:
return sys.modules[fullname]
except KeyError:
pass
try:
mod = self.exported_mods[fullname]
except KeyError:
raise ImportError('Unable to load %r' % fullname)
mod.__loader__ = self
sys.modules[fullname] = mod
return mod
_importer = CalcsImporter({
'new_file1': new_file1,
'new_file2': new_file2,
})
sys.meta_path.append(_importer)
and you should be able to do from calcs.new_file1 import foo
I have three files
helper.py
class helper:
def __init__(self, out_file):
self.out_file = out_file
def foo(first, second):
# Write data to file
flask_API.py
from helper import helper
#app.route('/', methods=['POST'])
def parse_request():
content = request.get_json()
out_file = #based on timestamp
helper(out_file).foo(content['first'], content['second'])
test_flask.py
import unittest
from unittest.mock import patch
import flask_API
class testFlaskAPI(unittest.TestCase):
def setUp(self):
self.app = flask_API.app.test_client()
self.app.test = True
#patch('flask_API.app.helper', return_value=None)
def test_service(self, mock_helper):
response = self.app.post(base_url, data=json.dumps({"some":"value"}, content_type='application/json')
self.assertEqual(response.status_code, status.HTTP_200_OK)
I am having trouble mocking the helper class. This gives me an error saying
AttributeError: <Flask 'flask_API'> does not have the attribute 'helper'
I read that a class/method needs to be mocked where it is being called instead of where it's defined. Is there something wrong with the way I am patching the class?
In the end the solution turned out to be fairly simple. First there was no need to add app in the #patch decorator. The test just needed #patch('flask_API.helper'). Second, I first needed to return the mock of the class and then mock the function call as well. So the final answer turned out to be
#patch('flask_API.helper')
def test_service(self, mock_helper):
mocking_helper = mock_helper.return_value # mocking the class
mocking_helper.foo.return_value = None
response = self.app.post(base_url, data=json.dumps({"some":"value"}, content_type='application/json')
self.assertEqual(response.status_code, status.HTTP_200_OK)
I am trying to write a pytest test for this function.
It looks for folders named like a day.
from settings import SCHEDULE
from pathlib import Path
import os
import datetime
def get_schedule_dates():
schedule_dates = []
for dir in os.listdir(SCHEDULE): # schedule is a path to a lot of directories
if Path(SCHEDULE, dir).is_dir():
try:
_ = datetime.datetime.strptime(dir, '%Y-%m-%d')
schedule_dates.append(dir)
except ValueError:
pass
return schedule_dates
Mocking os.listdir works fine. (when I turn off the isdir check)
from mymod import mycode as asc
import mock
def test_get_schedule_dates():
with mock.patch('os.listdir', return_value=['2019-09-15', 'temp']):
result = asc.get_schedule_dates()
assert '2019-09-15' in result
assert 'temp' not in result
Mocking pathlib's Path at the same time doesn't work:
def test_get_schedule_dates():
with (mock.patch('os.listdir', return_value=['2019-09-15', 'temp']),
mock.patch('pathlib.Path.isdir', return_value=True)):
result = asc.get_schedule_dates()
assert '2019-09-15' in result
assert 'temp' not in result
I get the error:
E AttributeError: __enter__
How can I mock both listdir and Path in the same call?
It looks like I can only use one mock per with statement,
testing this way works.
def test_get_schedule_dates():
with mock.patch('os.listdir', return_value=['2019-09-15', 'temp']):
with mock.patch('pathlib.Path.is_dir', return_value=True):
result = asc.get_schedule_dates()
assert '2019-09-15' in result
assert 'temp' not in result
I've written some python code that needs to read a config file at /etc/myapp/config.conf . I want to write a unit test for what happens if that file isn't there, or contains bad values, the usual stuff. Lets say it looks like this...
""" myapp.py
"""
def readconf()
""" Returns string of values read from file
"""
s = ''
with open('/etc/myapp/config.conf', 'r') as f:
s = f.read()
return s
And then I have other code that parses s for its values.
Can I, through some magic Python functionality, make any calls that readconf makes to open redirect to custom locations that I set as part of my test environment?
Example would be:
main.py
def _open_file(path):
with open(path, 'r') as f:
return f.read()
def foo():
return _open_file("/sys/conf")
test.py
from unittest.mock import patch
from main import foo
def test_when_file_not_found():
with patch('main._open_file') as mopen_file:
# Setup mock to raise the error u want
mopen_file.side_effect = FileNotFoundError()
# Run actual function
result = foo()
# Assert if result is expected
assert result == "Sorry, missing file"
Instead of hard-coding the config file, you can externalize it or parameterize it. There are 2 ways to do it:
Environment variables: Use a $CONFIG environment variable that contains the location of the config file. You can run the test with an environment variable that can be set using os.environ['CONFIG'].
CLI params: Initialize the module with commandline params. For tests, you can set sys.argv and let the config property be set by that.
In order to mock just calls to open in your function, while not replacing the call with a helper function, as in Nf4r's answer, you can use a custom patch context manager:
from contextlib import contextmanager
from types import CodeType
#contextmanager
def patch_call(func, call, replacement):
fn_code = func.__code__
try:
func.__code__ = CodeType(
fn_code.co_argcount,
fn_code.co_kwonlyargcount,
fn_code.co_nlocals,
fn_code.co_stacksize,
fn_code.co_flags,
fn_code.co_code,
fn_code.co_consts,
tuple(
replacement if call == name else name
for name in fn_code.co_names
),
fn_code.co_varnames,
fn_code.co_filename,
fn_code.co_name,
fn_code.co_firstlineno,
fn_code.co_lnotab,
fn_code.co_freevars,
fn_code.co_cellvars,
)
yield
finally:
func.__code__ = fn_code
Now you can patch your function:
def patched_open(*args):
raise FileNotFoundError
with patch_call(readconf, "open", "patched_open"):
...
You can use mock to patch a module's instance of the 'open' built-in to redirect to a custom function.
""" myapp.py
"""
def readconf():
s = ''
with open('./config.conf', 'r') as f:
s = f.read()
return s
""" test_myapp.py
"""
import unittest
from unittest import mock
import myapp
def my_open(path, mode):
return open('asdf', mode)
class TestSystem(unittest.TestCase):
#mock.patch('myapp.open', my_open)
def test_config_not_found(self):
try:
result = myapp.readconf()
assert(False)
except FileNotFoundError as e:
assert(True)
if __name__ == '__main__':
unittest.main()
You could also do it with a lambda like this, if you wanted to avoid declaring another function.
#mock.patch('myapp.open', lambda path, mode: open('asdf', mode))
def test_config_not_found(self):
...