Why is it important to create test data at the early stages of software development?

Creating test data at the initial stage of development is important for several reasons:

• It allows testing the correctness of functions and modules with real or near-real data.
• It helps identify errors and shortcomings in the program logic before integration with other components.
• It speeds up the debugging process, as there is a ready set of data for repeated testing.
• It ensures the stability of tests, which is important for automated testing.

For example, when developing an order processing function, pre-created test orders will help verify all scenarios — successful processing, data errors, boundary cases, etc.