Why Testing Is Essential for Your Software

Introduction

You would never buy a car that has not been tested. Yet software projects are delivered every day without proper tests. The result: bugs in production, frustrated users, and expensive emergency fixes.

In this article, we explain which types of tests exist, why they matter, and how we at MG Software use testing to deliver reliable software.

The Cost of Not Testing

"The cost of fixing a defect rises up to 15 times as the defect is detected later in the development process."

— IBM Systems Sciences Institute, Relative Cost to Fix Defects

A bug found during development takes minutes to fix. The same bug in production can cost hours of investigation, communication, and repair. Research by IBM and NIST shows that production bugs are up to 15 times more expensive to resolve.

Then there is user trust. An online store that crashes during peak hours, a form that loses data, or a calculation that shows wrong amounts: it costs you customers and reputation.

Types of Tests Explained

Unit tests verify individual functions in isolation, for example with Jest or Vitest. They are fast, cheap, and form the foundation of every testing strategy. Integration tests check whether different components work together correctly, for example whether your API communicates properly with the database.

End-to-end tests simulate real user scenarios using tools like Playwright or Cypress. They open a browser, click buttons, and verify that the expected result appears. These tests are slower but catch problems that other tests miss. For UI components specifically, visual regression testing with tools like Storybook and Chromatic catches visual bugs before they reach production.

Test Automation: One-Time Investment, Lasting Value

Manual testing is time-consuming and error-prone. With the right testing frameworks, automated tests run in seconds and can be re-executed with every code change. This is especially valuable during ongoing development.

At MG Software, our tests run automatically with every pull request. Code that fails the tests does not get merged. This guarantees that new features do not break existing functionality.

Our Approach at MG Software

We follow a test pyramid: many unit tests as the foundation, a layer of integration tests in the middle, and a targeted set of end-to-end tests at the top. This provides maximum coverage with minimal execution time.

For critical business logic, we always write tests upfront. For an invoicing module, we test every calculation, every rounding rule, and every edge case before a single line of code is written.

Testing in the Age of AI-Generated Code

Since AI coding assistants like Cursor and Claude Code became standard tooling in 2026, testing has become more important, not less. AI generates code faster than ever, but that code is convincingly written and therefore hard to judge at a glance. A generated function can look perfect and still miss an edge case that only surfaces with the thousandth user. The testing strategy has become the quality gate all code must pass through, regardless of who or what wrote it.

The good news: those same AI tools make writing tests cheaper. Where a solid test suite used to take twenty to thirty percent of development time, we now generate a large share of unit tests with AI and spend the saved time on the tests that require real thinking: integration tests across connections between systems and end-to-end scenarios that mimic actual user behavior. Net result: you get more test coverage for the same budget than a few years ago.

How Much Testing Is Enough: Our Rules of Thumb

The question clients ask us most often: where is the line? Chasing one hundred percent test coverage wastes your money, because the last twenty percent takes disproportionate time and catches hardly any additional bugs. Our rules of thumb after dozens of projects: business logic that money or personal data flows through gets full coverage, forms and API endpoints get tests on the happy path plus the known failure scenarios, and purely visual components are tested with a limited set of visual regression tests.

For an average custom software project like a client portal or dashboard, that comes down to roughly seventy to eighty percent coverage on the core and deliberately less on the edges. More important than the percentage is the question: if this test fails, do I immediately know what is broken? A small set of sharp tests beats a large set of vague tests, any day of the week.

Conclusion

Testing is not a luxury but a necessity. It saves you money in the long run, protects your reputation, and gives you confidence that your software does what it is supposed to do.

Curious how we ensure quality in our projects? Get in touch for a free consultation.