【软件测试】（homework3）覆盖问题

使用方法printPrimes()完成（a）~（f）题：

代码如下：

/******************************************************* 
     * Finds and prints n prime integers 
     * Jeff Offutt, Spring 2003 
     ******************************************************/ 
    public static void printPrimes (int n) 
    { 
        int curPrime; // Value currently considered for primeness 
        int numPrimes; // Number of primes found so far. 
        boolean isPrime; // Is curPrime prime? 
        int [] primes = new int [MAXPRIMES]; // The list of prime numbers. 
        
        // Initialize 2 into the list of primes. 
        primes [0] = 2; 
        numPrimes = 1; 
        curPrime = 2; 
        while (numPrimes < n) 
        { 
            curPrime++; // next number to consider ... 
            isPrime = true; 
            for (int i = 0; i <= numPrimes-1; i++) 
            { // for each previous prime. 
                if (isDivisible(primes[i], curPrime)) 
                { // Found a divisor, curPrime is not prime. 
                    isPrime = false; 
                    break; // out of loop through primes. 
                } 
            } 
            if (isPrime) 
            { // save it! 
                primes[numPrimes] = curPrime; 
                numPrimes++; 
            } 
        } // End while 
        
        // Print all the primes out. 
        for (int i = 0; i <= numPrimes-1; i++) 
        { 
            System.out.println ("Prime: " + primes[i]); 
        } 
    } // end printPrimes

(a) 控制流图：

(b) 考虑测试用例 t1=(n=3) 和 t2=(n=5)，当一个错误是数组越界错误时，t2比t1更容易发现错误。

(c) 当numPrimes < n时，会通过while循环体，所以当n=1时，可以不通过while循环。

(d)

节点覆盖：{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16}

边覆盖：{(1,2),(2,3),(2,12),(3,4),(4,5),(5,6),(5,9),(6,7),(6,8),(7,5),(8,9),(9,10),(9,11),(10,11),(11,2),(12,13),(13,14),(14,15),(15,13),(13,16)}

主路经覆盖：

{(1,2,3,4,5,6,7),

(1,2,3,4,5,6,8,9,10,11),

(1,2,3,4,5,6,8,9,11),

(1,2,3,4,5,9,10,11),

(1,2,3,4,5,9,11),

(1,2,12,13,14,15),

(1,2,12,13,16),

(2,3,4,5,6,8,9,10,11,2),

(2,3,4,5,6,8,9,11,2),

(2,3,4,5,9,10,11,2),

(2,3,4,5,9,11,2),

(3,4,5,6,8,9,10,11,2,12,13,14,15),

(3,4,5,6,8,9,11,2,12,13,14,15)

(3,4,5,6,8,9,10,11,2,12,13,16)

(3,4,5,6,8,9,11,2,12,13,16),

(3,4,5,9,10,11,2,12,13,14,15),

(3,4,5,9,11,2,12,13,14,15),

(3,4,5,9,10,11,2,12,13,16),

(3,4,5,9,11,2,12,13,16),

(5,6,7,5),

(6,7,5,9,10,11,2,12,13,14,15),

(6,7,5,9,11,2,12,13,14,15),

(6,7,5,9,10,11,2,12,13,16),

(6,7,5,9,11,2,12,13,16),

(14,15,13,16),

(13,14,15,13),}

*实现主路经覆盖的例子：