When faced with a situation where a developer is not testing their work, my first step would be to empathize and understand the reasons behind their actions. They might be feeling pressured, overwhelmed, or uncertain about how to perform effective testing. I might say something like: "I've noticed that there hasn't been much testing done on your tasks. I recognize that we are all facing significant pressure with this project. If you're struggling to find the time to thoroughly test your code, we can discuss this with our team lead to explore possible solutions, such as adjusting deadlines, implementing test automation, or providing additional support. Remember, we are a team, and we're here to help each other." Although bringing up this concern can be difficult, it is essential for ensuring the project's quality and fostering team efficiency and collaboration.