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🛠 Testing AWS Chalice Applications

📗 A tutorial to learn how to write unit tests and integration tests for REST APIs in AWS Chalice. Additionally, we will see how to measure test coverage.

TL;DR: In this tutorial, we will learn how to write unit tests and integration tests with Pytest in AWS Chalice applications. We will also learn how to measure test coverage.


AWS Chalice is a Python-based web micro-framework that leverages on the AWS Lambda and API Gateway services. It is used to create serverless applications. The Chalice experience is Flask-like by way of features like semantics and syntax. For more details on creating and deploying Chalice applications, you can go through the article on how to create CRUD REST API with AWS Chalice.

When building applications, there is a need to test the code to avoid shipping bugs and unstable code. It also saves one a lot of debugging hours and makes deployments less stressful.

Common forms of tests in software development include:

  1. Unit test: This tests a particular function, component, or logic in the code. This way, edge cases can easily be identified, isolated, and fixed. Unit tests usually involve inspecting the output of a function against a known or expected output.
  2. Integration Test: examines multiple parts or the entire application in an end-to-end manner. It considers how each function or component works with the other.

However, Chalice currently provides a test client for just unit tests. Therefore, the integration tests are written in a manner similar to unit tests with no major difference other than the fact that integration tests consist of multiple unit tests.

Where to Write Tests

In Python-based applications, tests are usually housed in files. These are the test files that will import the application logic to be tested.


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