Python Mock a Function Parameter - python

I have a function in myfile.py that accepts no arguments. Inside the function I am creating a pandas DataFrame based on the data returned from an API call shown as: df = pd.DataFrame(api_call_from_helper_function().all_the_data()). I am trying to mock the API call so it doesn't try to actually connect to the API. Below is my attempt:
myfile.py
def make_dataframe_from_data():
df = pd.DataFrame(api_call_from_helper_function().all_the_data())
return df
test_myfile.py
import pandas as pd
from unittest.mock import MagicMock
import myfile
from myfile import make_dataframe_from_data
def test_make_dataframe_from_data(monkeypatch):
mock_df = MagicMock()
mock_instance = MagicMock(return_value=mock_df)
monkeypatch.setattr("pd.DataFrame", mock_instance)
result = make_dataframe_from_data()
mock_instance.assert_called_once()
assert isinstance(result, pd.DataFrame())
In this code, the api_call_from_helper_function() uses another function I made to make the api call and the appended .all_the_data() returns all the data that it got. Right now my tests can mock the api call in api_call_from_helper_function() but I can't get it to mock when I pass it as a parameter to pd.DataFrame. What am I doing wrong?

Related

How to mock an import within an import

So I am trying to test an api lookup with my mock data.
I am testing a method within transform.py that imports a module lookup
import lookup
col = lookup.ColFinder()
url = "xyz"
if col.is_present(url):
do this
lookup.py
import secdata
class ColFinder():
def is_present(url):
if url in secdata.CUSTOM_STUFF:
return secdata.CUSTOM_STUFF[url]
secdata.py
secdata.CUSTOM_STUFF=load("some_file")
I want to mock the JSON (file being loaded within secdata.CUSTOM_STUFF)
I have tried mocking using the unittest.mock with some custom config within tests/resources
CUSTOM_CONFIG = secdata.load(os.path.join(os.path.dirname(__file__),'/resources/custom_config.json'))
import mock
#mock.patch("transform.lookup.secdata.CUSTOM_STUFF" , return_value=CUSTOM_CONFIG)
def test_blah_blah(self, *_):
but this doesn't seem to load the file I am trying to reference. Please can someone help me mock this, point out what am I doing wrong.
Thank you in advance.

Can not monkeypatch imported module

I have a very simple Google Cloud Function written in Python and it makes a reference to Google's Secret manager via their Python library.
The code is very simple and it looks like this:
import os
from google.cloud import secretmanager
import logging
client = secretmanager.SecretManagerServiceClient()
secret_name = "my-secret"
project_id = os.environ.get('GCP_PROJECT')
resource_name = "projects/{}/secrets/{}/versions/latest".format(project_id, secret_name)
response = client.access_secret_version(resource_name)
secret_string = response.payload.data.decode('UTF-8')
def new_measures_handler(data, context):
logging.info(secret_string)
print('File: {}.'.format(data['name']))
and then I have my simple unit test which is trying to take advantage of monkey patching:
import main
def test_print(capsys, monkeypatch):
# arrange
monkeypatch.setenv("GCP_PROJECT", "TestingUser")
monkeypatch.setattr(secretmanager, "SecretManagerServiceClient", lambda: 1)
name = 'test'
data = {'name': name}
# act
main.new_measures_handler(data, None)
out, err = capsys.readouterr()
#assert
assert out == 'File: {}.\n'.format(name)
Everything goes well with the mock for the environment variable but I can not mock secretmanager. It keeps on trying to call the actual API. My ultimate goal is to mock secretmanager.SecretManagerServiceClient() and make it return an object which later on can be used by: client.access_secret_version(resource_name) (which I will need to mock as well, I think)
See my answer to this question for a working example of using unittest patching and mocking to mock Google API calls and return mock results:
How to Mock a Google API Library with Python 3.7 for Unit Testing

How should I test a method of a mocked object

I have a question about how to mock a nested method and test what it was called with. I'm having a hard time getting my head around: https://docs.python.org/3/library/unittest.mock-examples.html#mocking-chained-calls.
I'd like to test that the "put" method from the fabric library is called by the deploy_file method in this class, and maybe what values are given to it. This is the module that gathers some information from AWS and provides a method to take action on the data.
import json
import os
from aws.secrets_manager import get_secret
from fabric import Connection
class Deploy:
def __init__(self):
self.secrets = None
self.set_secrets()
def set_secrets(self):
secrets = get_secret()
self.secrets = json.loads(secrets)
def deploy_file(self, source_file):
with Connection(host=os.environ.get('SSH_USERNAME'), user=os.environ.get("SSH_USERNAME")) as conn:
destination_path = self.secrets["app_path"] + '/' + os.path.basename(source_file)
conn.put(source_file, destination_path)
"get_secret" is a method in another module that uses the boto3 library to get the info from AWS.
These are the tests I'm working on:
from unittest.mock import patch
from fabric import Connection
from jobs.deploy import Deploy
def test_set_secrets_dict_from_expected_json_string():
with patch('jobs.deploy.get_secret') as m_get_secret:
m_get_secret.return_value = '{"app_path": "/var/www/html"}'
deployment = Deploy()
assert deployment.secrets['app_path'] == "/var/www/html"
def test_copy_app_file_calls_fabric_put():
with patch('jobs.deploy.get_secret') as m_get_secret:
m_get_secret.return_value = '{"app_path": "/var/www/html"}'
deployment = Deploy()
with patch('jobs.deploy.Connection', spec=Connection) as m_conn:
local_file_path = "/tmp/foo"
deployment.deploy_file(local_file_path)
m_conn.put.assert_called_once()
where the second test results in "AssertionError: Expected 'put' to have been called once. Called 0 times."
the first test mocks the "get_secret" function just fine to test that the constructor for "Deploy" sets "Deploy.secrets" from the fake AWS data.
In the second test, get_secrets is mocked just as before, and I mock "Connection" from the fabric library. If I don't mock Connection, I get an error related to the "host" parameter when the Connection object is created.
I think that when "conn.put" is called its creating a whole new Mock object and I'm not testing that object when the unittest runs. I'm just not sure how to define the test to actually test the call to put.
I'm also a novice at understanding what to test (and how) and what not to test as well as how to use mock and such. I'm fully bought in on the idea though. It's been very helpful to find bugs and regressions as I work on projects.

Python mock: AssertionError: Expected and actual call not same

I am new to unittest.mock library and unable to solve the issue I am experiencing.
I have a class called ‘function.py’ in the below folder structure
src
_ init.py
function.py
tests
init.py
test_function.py
In test_function.py I have some code like this:
import unittest
from unittest import mock
from ..src.function import get_subscriptions
from ..src import function
class TestCheckOrder(unittest.TestCase):
#mock.patch.object(function, 'table')
def test_get_subscriptions_success(self, mocked_table):
mocked_table.query.return_value = []
user_id = "test_user"
status = True
get_subscriptions(user_id, status)
mocked_table.query.assert_called_with(
KeyConditionExpression=conditions.Key('user_id').eq(user_id),
FilterExpression=conditions.Attr('status').eq(int(status)))
In function.py:
import boto3
from boto3.dynamodb import conditions
dynamodb = boto3.resource("dynamodb")
table = dynamodb.Table("Subscriptions")
def get_subscriptions(user_id, active=True):
results = table.query(
KeyConditionExpression=conditions.Key(
'user_id').eq(user_id),
FilterExpression=conditions.Attr('status').eq(int(active))
)
return results['Items']
If I run this I get the following exception:
**AssertionError: Expected call: query(FilterExpression=<boto3.dynamodb.conditions.Equals object at 0x1116011d0>, KeyConditionExpression=<boto3.dynamodb.conditions.Equals object at 0x111601160>)
Actual call: query(FilterExpression=<boto3.dynamodb.conditions.Equals object at 0x1116010f0>, KeyConditionExpression=<boto3.dynamodb.conditions.Equals object at 0x111601080>)**
Thanks in advance for helping me out.
The issue is that when you're calling assert_called_with in your test, you're creating new instances of conditions.Key and conditions.Attr. And as these instances are different from one we had in the actual call, there's a mismatch(check the hex ids shown in the traceback).
Instead of this you can fetch the kwargs from the function call itself and test their properties:
name, args, kwargs = mocked_table.query.mock_calls[0]
assert kwargs['KeyConditionExpression'].get_expression()['values'][1] == user_id
assert kwargs['FilterExpression'].get_expression()['values'][1] == int(status)

Using Magic mock to test Github Api

I am basically using magic mock and context manager to test my code, I was successfully able to mock my get_urls function, But I am having trouble mocking out my access_all_repos_pr(): function which contains data of PR newer than 7 days, can anyone help me out on how to mock that data.
Here is the test code for my get_urls():
import unittest
from mock import MagicMock, patch
from contextlib2 import ExitStack
from GithubAPIpackage.GithubAPI import get_urls
class Test_GithubApi(unittest.TestCase):
def test_get_urls_returns_valid_urls(self):
with ExitStack() as stack:
mock_get_urls = stack.enter_context(
patch("GithubAPIpackage.GithubAPI._fetch_url")
)
fake_data = {"current_user_repositories_url": "http://FAKEURL.com"}
mock_get_urls.return_value = fake_data
print(type(fake_data))
result = get_urls()
self.assertEqual(result, "http://FAKEURL.com")
I want to mock out the response for the function access_all_repo_pr, can anyone help me out in what I need to do exactly to create a mock for my access_all_repo_pr function. Do I need to refactor my code in some way? (relatively new to python)
what I am trying is:
class Test_GithubApi_newer_than_7_days(unittest.TestCase):
def test_access_all_repo_pr_returns_valid_response(self):
with ExitStack() as stack:
mock_access_all_repo_pr = stack.enter_context(
patch("GithubAPIpackage.GithubAPI._fetch_url")
)
fake_data = {"current_user_repositories_url": "http://myfakeurl.com"}
mock_access_all_repo_pr.return_value = fake_data
result = access_all_repo_pr()
self.assertEqual(result, "")
Since you are using requests under the hood, may I suggest using responses for your testing? Not trying to skirt the question, but in my experience, I have found this to be the path of least resistance when it comes to writing tests that deal with the requests module. The tests end up being a lot cleaner, safer, and easier to write.

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