Which statement is true about unit tests?

Unit tests are designed to test individual components of a system in isolation, ensuring that each part functions as intended. One of the key advantages of unit tests is that they provide the fastest feedback cycle among testing methodologies. This rapid feedback is essential for developers as it allows them to quickly identify and fix issues in the code during the development process.

Since unit tests are typically straightforward, focusing on small bits of functionality, they usually run in a matter of seconds, enabling developers to make changes and immediately verify whether those changes produce the desired outcome. This efficiency contrasts with longer feedback cycles characteristic of integration tests or system tests, which often assess interactions between multiple components and therefore take more time to execute.

In addition, unit tests are generally easier to set up and do not necessitate complex configurations or consume extensive resources like extensive integration testing environments or large databases. They thrive on being lightweight and targeted, reinforcing the speed at which developers can receive feedback on their code changes.