public DataSource createHikariDatasource(String url, String username, String password, String driver) {


        HikariConfig hikariConfig = new HikariConfig();
        hikariConfig.setDataSourceClassName(driver);
        hikariConfig.setUsername(username);
        hikariConfig.setJdbcUrl(url);
        hikariConfig.setPassword(password);
        hikariConfig.setConnectionTestQuery("show tables");
        DataSource ds = new HikariDataSource(hikariConfig);

            return ds;


    }

@Test
    public void createHikariCPDatasource() throws Exception {
        GreetingConfig greetingConfig = new GreetingConfig();

        String driver = "org.hsqldb.jdbc.JDBCDataSource";
        String url="jdbc:hsqldb:mem:testdb";
        String user = "SA";
        String password = "";


        logger.debug("get message data source");
        DataSource dataSource = greetingConfig.createHikariDatasource(url, user, password,driver);

        JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
        jdbcTemplate.execute(env.getProperty("init"));
        jdbcTemplate.execute(env.getProperty("insert"));

    }

com.zaxxer.hikari.pool.HikariPool$PoolInitializationException: Failed to initialize pool: null
    at com.zaxxer.hikari.pool.HikariPool.checkFailFast(HikariPool.java:524)
    at com.zaxxer.hikari.pool.HikariPool.<init>(HikariPool.java:118)
    at com.zaxxer.hikari.HikariDataSource.<init>(HikariDataSource.java:71)
    at org.cam.go.microservice.GreetingConfig.createHikariDatasource(GreetingConfig.java:233)
    at org.cam.go.microservice.GreetingConfigTest.createHikariCPDatasource(GreetingConfigTest.java:78)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)