Don't Mock What You Don't Own: A Better Way to Test Third-Party Dependencies
This article tackles a common problem in unit testing: handling third-party dependencies. Using a Docker repository client as an example, the author demonstrates the drawbacks of directly mocking third-party dependencies (like HTTP clients): tests become complex, brittle, and hard to understand. The proposed solution involves introducing a thin abstraction layer to decouple business logic from external dependencies, simplifying testing and improving code readability and maintainability. This approach not only leads to cleaner and more concise tests but also enhances the readability and maintainability of the business logic itself. While acknowledging exceptions, the author concludes that this principle helps write more elegant and maintainable tests in most cases.
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