AWS CDK Boto 3 Unit Testing - How to mock Boto3 secrets manager

Question

Anyone have ideas on how to mock a boto3 secrets manager client's get_secret_value method in a separate method without passing the client to the method? Stuck on this for days, now. Any ideas, links to possible working code on github would be appreciated.

Could you share whatever baseline code you have bro? – Allan Chua Feb 17 '22 at 01:22 — Allan Chua, Feb 17 '22 at 01:22
http://docs.getmoto.org/en/latest/docs/getting_started.html – Sachin Suresh Mar 03 '22 at 08:47 — Sachin Suresh, Mar 03 '22 at 08:47

score 1 · Answer 1 · answered Oct 06 '22 at 08:25

Boto3 has its own stubs, however i prefer to use python unittest.mock like below:

Your code in my_app

import boto3


def call_under_test():
    sm = boto3.client('secretsmanager')
    sm.get_secret_value(SecretId='my-secret')

Your test may look like below:

from unittest.mock import Mock, patch

import my_app


@patch('my_app.boto3.client')
def test_get_secret(mock_client: Mock):
    secret = {'SecretString': 'some-secret'}
    mock_client.return_value.get_secret_value.return_value = secret
    my_app.call_under_test()  # here is you unit to test
    mock_client.assert_called_with('secretsmanager')
    mock_client().get_secret_value.assert_called_with(SecretId='my-secret')

This is an excellent answer. In my case I was using pytest's [monkeypatch](https://docs.pytest.org/en/stable/how-to/monkeypatch.html) rather than unittest's patch, but what I was missing was the first `return_value` for the mock_client (forgetting that the `boto3.client` is actually a function). Either way this is so much simpler and idiomatic than using the stubber and/ or moto or similar. Nice work. — followben, May 22 '23 at 22:01

AWS CDK Boto 3 Unit Testing - How to mock Boto3 secrets manager

1 Answers1