End-to-end testing for Rust web services

This tutorial explores the process of testing a warp web application in Rust, focusing on integration and end-to-end tests. It walks through the creation of a small to-do app that integrates a database and external HTTP service, emphasizing the use of mocks to simulate external dependencies. While mocking can simplify testing by replacing real components with fake implementations, this approach may miss edge cases if the mock is flawed. The tutorial discusses the trade-offs of using real databases and web services in automated testing, considering factors like infrastructure, reproducibility, and speed. To demonstrate these concepts, the tutorial begins with basic mock solutions and progressively moves towards using real databases and HTTP services, ensuring the solution is fully automated and reproducible. It also covers the setup of testing environments, the use of the wiremock library for simulating external web services, and the integration of real HTTP requests to wiremock, culminating in full end-to-end tests that involve running the actual web service. The tutorial emphasizes the importance of understanding various testing techniques and their trade-offs to effectively test distributed web services.