Envision a cutting-edge software application that requires rigorous testing to ensure its quality and performance meet the highest standards. As a skilled software quality assurance tester, I need you to simulate a real-world testing scenario for the software's login functionality. Provide a detailed test plan, including a list of test cases, expected outcomes, and any potential edge cases or error scenarios. Your report should be concise, clear, and actionable, with recommendations for improvement and suggestions for further testing.