In a recent post, I wrote about how I used Claude Code to analyze the code for RestAssured.Net and then perform a refactoring action, using hand-written tests as the safety net. In that post, I wrote that I didn’t want Claude to touch the tests themselves, and why. I was still curious, though, to find out for myself what Claude was capable of in terms of writing tests.

On Test Automation is a platform dedicated to software testing, test automation, and quality assurance. Readers can find articles, tutorials, and resources on topics such as test automation frameworks, testing strategies, and continuous integration pipelines. Additionally, they can learn about software testing tools, test-driven development (TDD), and agile testing methodologies.

On Test Automation

An exploration of using Claude Code to generate API tests for a Spring Boot banking application, starting from scratch with only a prompt. Claude produced 23 passing tests in minutes, achieving 95% line coverage and 91% mutation coverage as measured by PITest. However, analysis revealed gaps: several critical code paths were missed (HTTP 500 handling, empty account list, boundary values), and 4 of the 23 tests (17%) were dead weight that didn't uniquely contribute to coverage. The author emphasizes that evaluating AI-generated tests requires domain knowledge, testing experience, and tools like mutation testing — simply accepting passing tests at face value risks a test suite full of holes.

Writing tests with Claude Code - part 1 - initial results

Testing the generated tests with mutation testing

Identifying dead weight in our test suite