我有一个旧应用程序,其中包含如下代码片段:
public class MyClass
{
public void executeSomeSqlStatement()
{
final Connection dbConn = ConnectionPool.getInstance().getConnection();
final PreparedStatement statement = dbConn.prepareStatement(); // NullPointerException, if ConnectionPool.getInstance().getConnection() returns null
}
}
我想编写一个单元测试,当ConnectionPool.getInstance().getConnection()返回 null时,它验证MyClass.executeSomeSqlStatement不会抛出NullPointerException 。
我怎样才能做到(模拟ConnectionPool.getInstance().getConnection())而不改变类的设计(不删除单例)?