What will happen if test functions do not start with "test_" in unittest?

In the context of Python's unittest framework, test functions that do not start with "test_" will not run automatically. The unittest framework is designed to identify test methods based on their naming convention. Specifically, it looks for methods that begin with "test_" to recognize them as tests to be executed.

If a method or function does not follow this naming convention, unittest will simply ignore it when discovering tests. This behavior is crucial for developers to ensure that the framework can effectively identify and execute all intended tests without confusion or manual specification.

While the other options may sound plausible, they do not accurately reflect how unittest operates. For example, there are no runtime errors triggered merely by using an incorrect naming convention, nor will such functions run in any capacity—they are entirely bypassed during testing. Understanding this naming convention is an essential aspect of working with the unittest framework effectively.