Bob shares a method for debugging hanging tests in Python using a tool called pytest-timeout. The discussion begins with a simple example of code and tests that initially run successfully, but then introduces a delay to simulate a hanging test. By installing the pytest-timeout plugin, users can set a timeout to automatically fail tests that exceed a specified duration, which helps identify and address the issue of slow-running tests. This approach is beneficial not only for simple test cases but also for more complex scenarios involving external modules, as demonstrated by modifying a request in the 'requests' library. Additionally, the text highlights an advanced use case where changing the timeout method to "thread" allows for a more detailed stack trace, aiding in debugging deeply nested issues. This technique ultimately aims to streamline the testing process, making it more efficient and effective for developers.