Marlene Mhangami

Playwright Lets Agents Test Feature Requests Before They Write Code

Microsoft’s Marlene Mhangami argues that AI-generated tests can make a codebase look healthier than it is, because agents often write tests that confirm their own implementation rather than validate the user-visible behavior a feature is meant to deliver. Her prescription is to reverse the common workflow: start from the feature request, have the agent write failing Playwright tests against expected behavior, then generate code to pass them. In a GitHub Copilot demo using the Playwright MCP server, she applies that approach to a toy-store search and filtering feature, with the browser showing the agent exercise the product experience directly.