Vaessl/docs/02-Preparation/04-Test-strategy.md

vaessl: Test strategy

Spring Boot Test Environment

1. Environment Parity

   Instead of testing against a mocked database or the development database, I created a mirrored test container. This allows the application to perform JPA operations against a real PostgreSQL instance that matches the production engine but uses a different port (5434) and database name (vaessl_test).

2. Profile-Driven Configuration

   I utilized the Spring Profiles mechanism. By tagging the test class with @ActiveProfiles("test"), Spring Boot ignores the standard application.yaml for specific keys and prioritizes src/test/resources/application-test.yaml.

   The configuration is moved out of the Java code and into YAML. This follows the "Separation of Concerns" principle.

   The file is placed in src/test/resources (a sibling to src/test/java). This is the standard Gradle "SourceSet" layout, ensuring the build tool automatically packages these settings only during the test phase.

3. Gradle Test Lifecycle

   I corrected the dependency graph in build.gradle.kts. While the Initializr provides "test slices" (like data-jpa-test), a full integration test requires the Spring Boot Starter Test core.

   This starter provides the YAML parsing engine and the SpringBootContextLoader.

Frontend Test environment

1. The Vitest Stack

   • Vitest: providing a unified configuration for both the development server and the test runner.

   • jsdom: Provides a lightweight browser environment in Node.js.

   • React Testing Library: Ensures tests are written from the user's perspective (DOM-based) rather than implementation details.

2. Dynamic Environment Configuration

   The vitest.config.ts is configured to be environment-aware. By using loadEnv, the test runner can access variables from .env files, allowing us to:

   • Dynamically set the Server Port (51204).

   • Handle Allowed Hosts (crucial for code-server or LXC environments where the public URL might change).

   • Inject environment-specific keys into the test.env context.

3. TDD Workflow (Red-Green-Refactor)

   The environment is optimized for a fast feedback loop.

   • npm run test: Runs Vitest in "Watch Mode," re-triggering tests instantly upon file changes.

   • npm run test:ui: Launches the Vitest UI, providing a visual graph of test suites and real-time failure reports.