### Question:
BaseDataSource { public abstract String driverClassSelector();  String getPrincipal(); void setPrincipal(String principal); abstract String driverClassSelector(); abstract DbType dbTypeSelector(); String getJdbcUrl(); void isConnectable(); String getUser(); void setUser(String user); String getPassword(); void setPassword(String password); void setAddress(String address); String getAddress(); String getDatabase(); void setDatabase(String database); String getOther(); void setOther(String other);  }### Answer:
@Test public void testDriverClassSelector() { String mysqlDriverClass = new MySQLDataSource().driverClassSelector(); Assert.assertEquals(Constants.COM_MYSQL_JDBC_DRIVER, mysqlDriverClass); String clickHouseDriverClass = new ClickHouseDataSource().driverClassSelector(); Assert.assertEquals(Constants.COM_CLICKHOUSE_JDBC_DRIVER, clickHouseDriverClass); String db2ServerDriverClass = new DB2ServerDataSource().driverClassSelector(); Assert.assertEquals(Constants.COM_DB2_JDBC_DRIVER, db2ServerDriverClass); String oracleDriverClass = new OracleDataSource().driverClassSelector(); Assert.assertEquals(Constants.COM_ORACLE_JDBC_DRIVER, oracleDriverClass); String postgreDriverClass = new PostgreDataSource().driverClassSelector(); Assert.assertEquals(Constants.ORG_POSTGRESQL_DRIVER, postgreDriverClass); String sqlServerDriverClass = new SQLServerDataSource().driverClassSelector(); Assert.assertEquals(Constants.COM_SQLSERVER_JDBC_DRIVER, sqlServerDriverClass); String hiveDriverClass = new HiveDataSource().driverClassSelector(); Assert.assertEquals(Constants.ORG_APACHE_HIVE_JDBC_HIVE_DRIVER, hiveDriverClass); String sparkDriverClass = new SparkDataSource().driverClassSelector(); Assert.assertEquals(Constants.ORG_APACHE_HIVE_JDBC_HIVE_DRIVER, sparkDriverClass); }