slongle

Software Construction之Test and Exception

 
  • Jun 22, 2019

Exception

checked and unchecked exception

checked exception:要handle的exception，如：找不到xxx
unchecked exception:不handle，直接退出的exception，如Null­Pointer­Exception
不用handle的是unchecked，用handle的是checked

Exception类是checked exception
RuntimeException和Error类是unchecked exception

Javadoc

checked exception需要注释，unchecked exception和error不需要

/**
 * @throws NotPerfectSquareException if x it not a perfect square
 */
int integerSquareRoot(int x) throws NotPerfectSquareException{
    ...
}

定义和抛出异常

public class NotPerfectSquareException extends Exception {
    public NotPerfectSquareException() { super(); }
    public NotPerfectSquareException(String message) { super(message); }
    public NotPerfectSquareException(String message, Throwable cause) { super(message, cause); }
    public NotPerfectSquareException(Throwable cause) { super(cause); }
}
/**
 * @throws NotPerfectSquareException if x it not a perfect square
 */
int integerSquareRoot(int x) throws NotPerfectSquareException{
    throws new NotPerfectSquareException();
}

Exception的执行

try{
    A;
    B;
}
catch(Exception1 e1){
    C;
}
final{
    D;
}

无论怎么执行try和catch，最后都会执行final中的内容
当A结束时出现异常，如果被捕获就执行C,D，如果没被捕获直接执行D然后退出

Test

Test Strategy

白盒测试

针对代码执行路径设计测试，要求全覆盖

黑盒测试

只考虑spec

等价类划分

正负，奇偶，整数非整数，具体某格式和非该格式，长度限制，数据上限

考虑边界值

边界值及边界值附近

/*
 * Testing Strategy
 * 
 * Partition the inputs as follow
 * text.length() : 0, 1, >1
 * start : 0, 1, 1<start<text.length(), text.length()-1, text.length()
 * text.length()-start : 0, 1, even>1, odd>1 
 * 
 * Include ... because ...
 *
 */


// cover text.length() = 0
//       start = text.length = 0         
@Text
public void testXXX(){
    ...
}
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