unit-test-config-properties

Use ApplicationContextRunner to register and bind @ConfigurationProperties in isolation. This approach validates property mappings, type conversions, and nested structures in unit tests without initializing the entire Spring context, providing fast feedback during development.

Yes. ApplicationContextRunner lets you set environment-driven property values and assert that defaults and overrides work correctly. Test profile-based variations and confirm bindings respect your configuration without full application startup.

You need spring-boot-configuration-processor, spring-boot-starter-test, junit-jupiter, and assertj-core. These provide the tools to register properties, run isolated Spring contexts, and assert binding results in unit tests.

ApplicationContextRunner supports binding nested @ConfigurationProperties and asserting their values. Write unit tests that bind hierarchical properties and use assertions to confirm structure validation and constraint compliance without full context initialization.

Unit tests with ApplicationContextRunner run faster and isolate configuration logic from the full application stack. This enables rapid feedback when property names, types, or defaults change, speeding up development cycles.

Yes. The Skill applies to both Maven and Gradle. Add the required dependencies via your build tool, then use ApplicationContextRunner in unit tests to validate @ConfigurationProperties bindings independently of your build system.