To prevent data leakage between tests, use the refresh attribute in @AutoConfigureEmbeddedDatabase. This resets the database to its initial state (including reverting committed changes) using fast template database copying rather than standard transaction rollbacks.

Available refresh modes:

• AFTER_CLASS: Refreshes the database after each test class completes.
• AFTER_EACH_TEST_METHOD: Refreshes the database after every individual test method.

Note: If no refresh mode is specified, all tests in the project will share the same database instance.

@ExtendWith(SpringExtension.class)
@AutoConfigureEmbeddedDatabase(refresh = AFTER_EACH_TEST_METHOD)
public class EmptyDatabaseIntegrationTest {

    @Test
    void testMethod1() {
        // fresh database
    }

    @Test
    void testMethod2() {
        // fresh database
    }
}

The library supports multiple database providers, allowing you to choose between flexibility (Docker) and speed (Native providers like Zonky). You can configure a provider globally via the zonky.test.database.provider property or per-class using the @AutoConfigureEmbeddedDatabase(provider = ...) annotation.

By default, the library uses background bootstrapping for DataSource initialization and Flyway/Liquibase migrations.

Instead of waiting for migrations to finish, the library immediately returns a DataSource proxy. The first actual call to a data source method will block until bootstrapping is complete. To maximize the benefits of this mode, avoid calling the data source inside the @PostConstruct or init methods of related beans.

To use PostgreSQL as your embedded database, add the PostgreSQL JDBC driver to your Maven dependencies. The PostgreSQL provider supports all available features, including template databases and database prefetching, for maximum performance.

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <version>42.7.10</version>
</dependency>

The project uses Gradle.

Prerequisites:

• Git
• JDK 8 or later (ensure JAVA_HOME points to the JDK folder).

Steps:

1. Clone the repository: git clone git@github.com:zonkyio/embedded-database-spring-test.git
2. Run the build: ./gradlew build

Flyway is highly optimized in this library. Adding the flyway-core dependency enables support. For enhanced testing, you can add the flyway-spring-test extension to use the @FlywayTest annotation.

Processing of @FlywayTest is internally optimized to use database prefetching and template databases (where supported) to speed up applying new migrations after a database clean.

<!-- Core Flyway -->
<dependency>
    <groupId>org.flywaydb</groupId>
    <artifactId>flyway-core</artifactId>
    <version>11.20.3</version>
</dependency>

<!-- Optional: Flyway Test Extensions for @FlywayTest -->
<dependency>
    <groupId>org.flywaydb.flyway-test-extensions</groupId>
    <artifactId>flyway-spring-test</artifactId>
    <version>10.0.0</version>
    <scope>test</scope>
</dependency>

To use MySQL, add the mysql-connector-java dependency.

Performance Note: The MySQL provider only supports basic features required for embedded database operation. You may notice performance degradation because MySQL treats database and schema as synonymous, making database prefetching difficult, and it lacks support for fast binary backups required for template database emulation.

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.33</version>
</dependency>

The library automatically registers context customizers and test execution listeners. To disable this, exclude the embedded-database-spring-test-autoconfigure dependency from your Maven configuration.

<dependency>
    <groupId>io.zonky.test</groupId>
    <artifactId>embedded-database-spring-test</artifactId>
    <version>2.8.0</version>
    <scope>test</scope>
    <exclusions>
        <exclusion>
            <groupId>io.zonky.test</groupId>
            <artifactId>embedded-database-spring-test-autoconfigure</artifactId>
        </exclusion>
    </exclusions>
</dependency>

To use Liquibase, add the liquibase-core dependency. Since Liquibase does not have a direct equivalent to @FlywayTest, it is recommended to use the library's refresh mode to refresh the embedded database during tests.

<dependency>
    <groupId>org.liquibase</groupId>
    <artifactId>liquibase-core</artifactId>
    <version>5.0.2</version>
</dependency>

The Docker provider is the default. It is ideal for testing database extensions or custom Docker images. Use @AutoConfigureEmbeddedDatabase without arguments to use it.

Docker-specific configuration: Configure images and tmpfs settings using the zonky.test.database.<db-type>.docker group (e.g., postgres, mysql, mariadb, mssql).

Customization via Bean: Implement PostgreSQLContainerCustomizer to customize the container (e.g., setting startup timeouts).

@ExtendWith(SpringExtension.class)
@AutoConfigureEmbeddedDatabase
public class DefaultProviderIntegrationTest {
    // class body...
}

@Bean
public PostgreSQLContainerCustomizer postgresContainerCustomizer() {
    return container -> container.withStartupTimeout(Duration.ofSeconds(60L));
}

The Yandex provider is deprecated and scheduled for removal. Use the Zonky provider instead.

Setup:

1. Add ru.yandex.qatools.embed:postgresql-embedded dependency.
2. Use @AutoConfigureEmbeddedDatabase(provider = YANDEX).

Configuration: Use zonky.test.database.postgres.yandex-provider.postgres-version to specify the EnterpriseDB PostgreSQL binary version.

<dependency>
    <groupId>ru.yandex.qatools.embed</groupId>
    <artifactId>postgresql-embedded</artifactId>
    <version>2.10</version>
    <scope>test</scope>
</dependency>

zonky.test.database.postgres.yandex-provider.postgres-version=11.10-1