Your question is Feature Design and Test Planning. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You've been asked to shape a new product feature before delivery begins. You need to turn a broad idea into a clear design and a practical test plan so engineering, QA, and business stakeholders are aligned on what will be built and how it will be validated.
How do you approach feature design and test planning?