Which characteristics are desirable in a unit test?

In the context of unit testing, one of the most desirable characteristics is that each test is independent of other unit tests. This independence allows developers to run tests in isolation without influencing one another, ensuring that the outcome of a test does not depend on the results of others. This guarantees that any failures can be traced back to the specific unit being tested, facilitating easier debugging and maintenance.

When tests are independent, it also provides the benefits of parallel execution, reducing the time taken to run the full test suite, and enhancing the reliability of the testing process. This characteristic is essential for building a robust testing framework that supports continuous integration and deployment practices.

Moreover, having independent tests encourages better test design and leads to more reliable software quality, as changes to one part of the code will not inadvertently break tests for other parts of the codebase. This contrasts with tests that are dependent on one another, where a failure in one could propagate issues and obscure the source of the problem. Overall, independence among unit tests is a fundamental principle in achieving effective and maintainable testing strategies.