Beyond Mocks Messing with Our Preconceptions of Testing

ElixirConf · June 12, 2025, 1:00pm

ElixirConf US 2024 - Nicholas Henry
Welcome to ElixirConf

Topic: Testing

In this session, “Beyond Mocks: Messing with Our Preconceptions of Testing,” we will experiment with a different approach to testing in Elixir that steps away from traditional reliance on mocks. If you’ve ever been frustrated by broken tests that break every time you refactor, this talk might offer you a fresh perspective.

We’ll begin by discussing the challenges of using test mocks and how they can sometimes lead to unreliable test results. From there, I’ll introduce you to the Nullable pattern, an experimental technique applied to testing with external dependencies in Elixir. Instead of leaning on test mocks, this technique uses “nullable infrastructure wrappers” as an attempt to simplify dependencies and make your tests more robust and easier to maintain.

I’ll walk you through practical examples of how I tried to apply the patterns of Nullables in Elixir. While this approach is in development, it could offer a new way to think about testing that better aligns with Elixir’s strengths. And perhaps even make you use test mocks with clearer intent.

By the end of our time together, my goal is to encourage you to experiment with your own testing strategies, exploring how alternative techniques might lead to cleaner, more effective code. Let’s dive into this experiment and challenge our preconceptions about testing!

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