The Difficulty and Value of Unit Testing

Unit testing is valuable, but challenging to do well and can lead to a brittle suite of tests if not done carefully. It is important to focus on mitigating risks with unit tests for more risky components, while acknowledging that test-driven development is a difficult skill to master but provides significant value. However, it's important to note that there is a learning curve, and initially, it may slow down development speed. Unit testing enforces an easy-to-test architecture and works well for modules handling corner cases, but may not be beneficial during the prototype stage when rapidly answering unknowns. Therefore, it's not advisable to focus on extensive unit testing during the prototype stage or when trying to validate product feasibility.