Mocks on spring project

Project sampling test scenarios using spring capabilities.

Requirements

• java 21
• docker 28

Project setup

Using spring initializer, scaffold a project.

Add this extra dependency:

<dependency>
    <groupId>org.testcontainers</groupId>
    <artifactId>postgresql</artifactId>
    <scope>test</scope>
</dependency>

Using docker, spin a postgresql database:

docker run --rm -d \
  --name pg-database -p 5432:5432 \
  -e POSTGRES_PASSWORD=enterprise \
  -e POSTGRES_USER=enterprise \
  -e POSTGRES_DB=products \
  postgres:16-alpine

Modify TestcontainersConfiguration to provide a test database:

// ...
@TestConfiguration(proxyBeanMethods = false)
class TestcontainersConfiguration {

    @Bean
    @ServiceConnection
    fun postgresContainer(): PostgreSQLContainer<*> = PostgreSQLContainer(
        DockerImageName.parse("postgres:16-alpine")
    ).withEnv(
        mapOf(
            "POSTGRES_DB" to "products",
            "POSTGRES_USER" to "enterprise",
            "POSTGRES_PASSWORD" to "enterprise"
        )
    )
}

Finally add the default liquibase configuration and the fist migration:

mkdir -p src/main/resources/db/changelog/migrations
touch src/main/resources/db/changelog/migrations/2025-05-01-initial-schema.sql
touch src/main/resources/db/changelog/db.changelog-master.yaml

And that's it, the project is

How to build

./mvnw package

How to run

./mvnw springboot:run

How to test

./mvnw test

Noteworthy

• avoid the org.junit.Test annotation, use the new one at org.junit.jupiter.api.Test