TaxLens

Minimal Java web app that returns simplified capital gains tax (CGT) info by country.

Frontend

• A small Tailwind UI is available at src/main/resources/static and served from the application root.

Quick run

• Requirements: Java 17, Maven
• Start the app:

mvn spring-boot:run

Open the UI: http://localhost:8080 API endpoint: http://localhost:8080/api/cgt?country=DE

Testing

• Run the full test suite:

mvn test

• Run a single test class (example):

mvn -Dtest=com.taxlens.service.CgtServiceTest test

• Run a single test method (example):

mvn -Dtest=com.taxlens.service.CgtServiceTest#usesExternalWhenConfigured test

Notes on tests

• Tests use spring-boot-starter-test (JUnit, Mockito, MockMvc).
• CgtServiceTest covers the fallback JSON and the external-provider path (mocked RestTemplate).
• CgtControllerTest uses @WebMvcTest and a mocked CgtService to verify the HTTP layer.

Configuration

• To enable an external CGT provider, set cgt.external.url in src/main/resources/application.properties or as an environment property. Example:

cgt.external.url=https://example.com/api/cgt

Fallback data

• The application ships a fallback JSON at src/main/resources/cgt-fallback.json used when no external provider is configured or when the external call fails.

Development tips

• To build the runnable JAR:

mvn -DskipTests package

• To run the packaged JAR:

java -jar target/taxlens-0.0.1-SNAPSHOT.jar

Questions or next steps

• Add CI to run tests on push (I can add a GitHub Actions workflow).
• Add code coverage reporting (Jacoco) if you want coverage metrics.