การจัดระเบียบการทดสอบด้วย @DisplayName และการซ้อนกลุ่ม

A test suite is more than a safety net — it documents how your code should behave. JUnit 5’s @DisplayName and @Nested make that documentation shine.

A name like testAdd2 says almost nothing, and method names can’t hold spaces or punctuation — so they can only be so expressive.

@DisplayName gives a test any readable label — spaces, punctuation, even emoji. Reports show the label instead of the method name.

Put @DisplayName on the test class too, to describe the whole unit under test in plain language.

Don’t want to annotate every method? A display name generator turns method names into readable text automatically.

Related tests often share context — “cart is empty” vs “cart has items.” @Nested classes group them so structure mirrors behavior.

Annotate an inner, non-static class with @Nested and its tests run inside the outer class’s lifecycle.

Each nested class can have its own @BeforeEach, setting up that group’s specific context without touching its siblings.

Together, display names and nesting produce reports that read like specs: “Calculator → when adding → adds two positives.” Intent at a glance.

This structure naturally fits a given-when-then style, so your tests double as a living behavior spec for the class under test.

Write self-explaining suites: name tests by behavior not method, group scenarios with @Nested, give each its own setup, aim for sentence-like reports.

@DisplayName or @Nested — which one builds the spec-like report?

You organized tests for clarity: @DisplayName labels them, generators automate naming, and @Nested groups scenarios into a readable spec.