SpringApplicationBuilder appBuilder = new SpringApplicationBuilder();
appBuilder.headless(false);
appBuilder.listeners(new ApplicationListener<ApplicationEvent>() {
    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof ApplicationEnvironmentPreparedEvent) {
            Environment env = ((ApplicationEnvironmentPreparedEvent) event).getEnvironment();
            String datasourceUrl = env.getProperty(RepositoryConfig.JDBC_URL_PROPERTY);

            File db = FirebirdUtil.extractDatabaseFile(datasourceUrl);
            if (db != null) {
                String user = env.getProperty(RepositoryConfig.JDBC_USER_PROPERTY);
                String password = env.getProperty(RepositoryConfig.JDBC_PASSWORD_PROPERTY);

                // this will create the FDB file if it doesn't exists
                FirebirdUtil.createDatabaseifNotExists(db, user, password);
            }
        }
    }
});

@RunWith(SpringRunner.class)
@SpringBootTest
@ContextConfiguration(loader = CustomLoader.class)
public class DemoApplicationTests {

public static class CustomLoader extends SpringBootContextLoader {

    @Override
    protected SpringApplication getSpringApplication() {
        SpringApplication app = super.getSpringApplication();
        app.addListeners(new MyListener());
        return app;
    }
}