Practical Test Code Writing Tips Part 3: Escaping Given Hell - The Limits of Object-Based Data Setup

Complex data setup in the Given stage of test code blurs the main focus of the test and makes it difficult to secure test coverage. Especially in structures like order systems, where multiple elements such as products, members, and coupons are intricately intertwined, data setup itself becomes a heavy burden for developers.

As requirements become more complex, object-based data setup faces the following problems:

• Setting up complex object structures: Every time a field is added, objects must be manually created and dependencies configured, which reduces code readability.
• Handling nested data structures: Nested structures, such as a list within another list, increase code complexity and are prone to mistakes.
• Difficulty maintaining data format consistency: When API specs change (CamelCase/SnakeCase, etc.), all object creation logic must be modified, which is cumbersome.
• Constraints on testing invalid data: When values are restricted at the object creation stage, as with Enum types, it becomes difficult to test abnormal data input scenarios.

To solve these problems, data setup using JSON files can be utilized. Using JSON files allows data structures to be defined intuitively, improving code readability and maintainability, and lets test code focus on verifying the main concern of the test rather than on object serialization.