Mastering Spring Cloud in Testing

Overview

This repository implements a microservices architecture using Spring Boot 3.x and Spring Cloud 2025.x, built and managed with Maven. It includes the following services:

• gateway-service: API gateway routing external requests
• discovery-service: Eureka-based service registry
• account-service: Manages user account data
• customer-service: Handles customer profiles
• order-service: Processes orders and payments
• product-service: Manages product catalog

Each service exposes REST endpoints, registers with Eureka for discovery, and uses Spring Boot’s convention-over-configuration model.

Architecture

The diagram below illustrates service interactions and the Eureka registry:

graph LR
  GW[Gateway Service] -->|REST| ACC[Account Service]
  GW --> CUS[Customer Service]
  GW --> ORD[Order Service]
  ORD --> PROD[Product Service]
  subgraph Infra
    DISC[Discovery Service]
  end
  GW -. registration .-> DISC
  ACC -. registration .-> DISC
  CUS -. registration .-> DISC
  ORD -. registration .-> DISC
  PROD -. registration .-> DISC

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Service Ports

Service	Port
gateway-service	8080
account-service	8081
customer-service	8082
order-service	8083
product-service	8084
discovery-service	8761

Automated Tests

The table below summarizes the test statistics collected across all modules:

Service	Test files	JUnit4	JUnit5	@SpringBootTest	Testcontainers
gateway-service	12	0	12	5	1
account-service	9	0	9	4	0
customer-service	7	0	7	3	0
order-service	15	2	13	6	2
product-service	11	0	11	4	1
discovery-service	3	0	3	1	0

Test Layers

• Unit Tests

  • Framework: JUnit 5
  • Assertions: AssertJ
  • Mocking: Mockito
  • Location: src/test/java
  • Fast, isolated verification of individual components without Spring context.

• Integration Tests

  • Annotation: @SpringBootTest
  • Starts full Spring context to validate end-to-end behavior.
  • Uses Testcontainers (in order-service and gateway-service) for realistic external dependencies.

Build & Run

Use the Maven wrapper to compile, test, and package all modules:

./mvnw clean install

If you need to start external dependencies for integration tests:

docker compose -f docker-compose-test.yml up -d   # if docker-compose-test.yml is present

To run an individual service in development mode:

./mvnw -pl gateway-service spring-boot:run

Roadmap / Future Work

• Increase unit test coverage for modules with low current coverage
• Integrate JaCoCo for automated code-coverage reporting
• Migrate remaining JUnit4 tests to JUnit5
• Implement contract testing via Spring Cloud Contract
• Enhance CI/CD pipelines with quality gates and automated promotions