public class DataSource {
    private static HikariConfig config = new HikariConfig();
    private static HikariDataSource ds;
 
    public static HikariDataSource getDataSource() {
        if (ds == null) {
            config.setJdbcUrl(System.getProperty("jdbcUrl","jdbc:postgresql://localhost:5433/postgres"));
            config.setUsername(System.getProperty("jdbcUser","postgres"));
            config.setPassword(System.getProperty("jdbcPassword","postgres"));
            ds = new HikariDataSource(config);
 
            initDatabase();
        }
        return ds;
    }
 
    private static void initDatabase() {
        try {
            DatabaseConnection connection = new JdbcConnection(ds.getConnection());
            Database database = DatabaseFactory.getInstance().findCorrectDatabaseImplementation(connection);
            Liquibase liquibase = new Liquibase(
                    System.getProperty("liquibaseFile","liquibase.xml"),
                    new ClassLoaderResourceAccessor(),
                    database);
            liquibase.update(new Contexts());
        } catch (SQLException | LiquibaseException e) {
            throw new RuntimeException(e);
        }
    }
 
    public static Connection getConnection() throws SQLException {
        return ds.getConnection();
    }
}

public class Base {
 
    @BeforeAll
    static void setup() {
        System.setProperty("jdbcUrl", "jdbc:h2:mem:test_" + UUID.randomUUID());
        System.setProperty("jdbcUser", "sa");
        System.setProperty("jdbcPassword", "");
        System.setProperty("liquibaseFile", "liquibase_test.xml");
    }
 
    @BeforeEach
    void init() {
        setup();
    }
}