Testing behaviors

This guide walks you through establishing a testing environment for Elixir applications using Ecto. It covers setting up a test database with Docker, configuring your environment for isolated tests, and integrating tools like ExMachina and Faker to simplify test data generation. The post demonstrates how to write effective tests for database operations, ensuring that your application’s core behaviors are thoroughly validated.

A DSL for testing schemas and changesets

Learn how to create a domain-specific language (DSL) for testing Ecto schemas and changesets in Elixir using ExUnit’s CaseTemplate. This post details the process of setting up a ModelCase to streamline test setup and reduce boilerplate, along with creating helper functions for validating schema fields, generating test data, and ensuring that changesets handle both valid and invalid data as expected. The approach allows for more efficient and maintainable test cases.

Patterns for Phoenix LiveView

Discover how to develop a domain-specific language (DSL) for testing Phoenix LiveView components with ExUnit’s CaseTemplate. This post shows you how to structure your ConnCase module to incorporate essential helpers and setup functions, making tests more effective and maintainable. It covers testing various LiveView scenarios, including rendering components, handling form submissions, and validating list and detail views. By centralizing logic and reducing redundancy, this approach helps validate meaningful behaviors while minimizing sensitivity to non-essential code changes.

Managing external services with dependency injection

Explore how to effectively manage and switch between external services in Elixir using dependency injection. This post demonstrates how to define service contracts using behaviors, implement different service modules for development and production, and dynamically configure these services at runtime. By decoupling service implementation from usage, this approach ensures flexibility and maintainability, making it easier to upgrade or replace services without risking regressions in your application.

Mocking external services

Learn how to mock external services in Elixir tests to avoid the fragility of relying on live service calls. This post demonstrates how to use the Mox library to create controlled mock versions of services, ensuring predictable and deterministic test outcomes. It covers the implementation of stubs that simulate various responses from the external service, ensuring that both successful and failure scenarios are thoroughly tested.

Why good testing practices matter

This post explores the broader impact of poor testing practices on team culture and project success. It highlights how inadequate testing can lead to a decline in professional standards, increased stress, and disengagement. Practical strategies are provided for implementing effective testing in Phoenix/Elixir projects, including layered testing, leveraging metaprogramming to create a domain-specific language (DSL), and focusing on creating resilient, descriptive tests. The post underscores the importance of taking responsibility for safeguarding the assumptions in your code and maintaining software integrity over time.