What makes a good test

Dan Fleser
3 min readJan 19, 2024


Testing is not just a routine procedure but a critical element that aligns with specific goals. Understanding these goals is essential in evaluating the value of each test.

Automated testing, in particular, offers a plethora of benefits that are technical, economical, and organizational.

Let’s delve into some of these advantages to better appreciate the value of a well-conceived test.

Time and Cost Efficiency

One of the primary benefits of testing is its ability to save time and money in the long run. By addressing software issues early in the development process, testing helps prevent bugs from escalating into major problems.

This proactive approach is not only more manageable but also significantly less expensive than dealing with issues post-release. Quality assurance, though time-consuming and costly in itself, is an investment that pays off by preventing the far greater expenses and time loss associated with releasing faulty software.

The Economic Perspective: Cost-Effectiveness

A test’s value can also be measured in terms of its cost-effectiveness. A valuable test prevents significant bugs, which could render an application unusable while being relatively inexpensive to write.

This balance between cost and benefit is crucial in determining a test’s worth.

Clarifying and Documenting Requirements

Testing serves a dual purpose of formalizing and documenting software requirements. A comprehensive test suite acts as a formal, easily understandable guide of expected code behavior, benefiting both the original developers and their peers.

This clarity helps in maintaining a consistent understanding of the project’s requirements and challenges.

Descriptive Nature of Tests

Effective tests are descriptive; they clearly articulate the expected behavior of the implementation code.

They use appropriate language to communicate requirements to developers and enumerate the various scenarios the code must handle.

Comprehensive Coverage

Valuable tests are those that encompass a wide range of scenarios, including both success and error cases. They cover correct and incorrect inputs, expected situations, and exceptional circumstances.

This thoroughness ensures that the code not only meets the current requirements but is also robust against potential future anomalies.

Safeguarding Against Regressions

A crucial aspect of testing is its role in facilitating safe changes and updates to the code. Automated tests are designed to ensure that the code continues to function as expected even after modifications.

This safety net makes implementing new features and refactoring existing code much less risky.

Preventing Breakage

Finally, a test proves its worth by how effectively it prevents code breakage. A valuable test is designed to fail when essential code is altered or removed inappropriately, yet remains unaffected by changes to unrelated code.

This specificity ensures that tests are sensitive to crucial modifications while being robust against irrelevant changes.

In conclusion, the value of a test in software development cannot be overstated. It lies not just in its ability to find flaws but in its cost-effectiveness, descriptive nature, comprehensive coverage, and ability to safeguard against regressions and prevent breakage.

As such, testing is an indispensable tool in the arsenal of any software development team, underpinning the quality and reliability of the software they produce.



Dan Fleser

I work as a full-time software engineer, 8+ years of experience. I recently switched from an 8-5 job to freelancing, which is going great. Follow me on YouTube.