homework3:课本习题练习
首先,本次要求是找出质数,书上给的代码如下:
private 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 (isDivisable(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
问题1:画出该方法的控制流图
答:如下。
问题2:考虑测试用例t1=(n=3)和t2=(n=5)。即使这些测试用例经过printfPrimes()方法中相同的主路径,他们不一定找出相同的错误。设计一个简单的错误,使得t2比t1
更容易发现。
答:数组越界时可能会发生错误,如令MAXPRIMES=4。
问题3:找到一个测试用例,使得测试路径不用通过while循环体。
答:令初始条件n=1。
问题4:列举每个节点覆盖,边覆盖和主路径覆盖的测试需求。
点覆盖: {1,2,3,4,5,6,7,8,9,10,11,12}
边覆盖:{(1,2),(2,3),(2,10),(3,4),(4,5),(4,8),(5,6),(5,7),(6,4),(7,8),(8,2),(8,9),(9,2),(10,11),(10,12),(11,10)}
主路径覆盖: {(1,2,3,4,5,6),
(1,2,3,4,5,7,8,9),
(1,2,10,11),
(1,2,10,12),
(2,3,4,5,7,8,9,2),
(2,3,4,5,7,8,2)
(2,3,4,8,9,2),
(2,3,4,8,2)
(3,4,5,7,8,9,2,10,11,12),
(3,4,5,7,8,9,2,10,11,13),
(3,4,5,7,8,2,10,11,12),
(3,4,5,7,8,2,10,11,13),
(4,5,6,4),
(4,5,7,8,9,2,3,4),
(4,5,7,8,2,3,4),
(4,8,2,3,4),
(4,8,9,2,3,4),
(5,6,4,5),
(5,6,4,8,9,2,10,11,12),
(5,6,4,8,9,2,10,11,13),
(5,6,4,8,2,10,11,12),
(5,6,4,8,2,10,11,13),
(6,4,5,6),
(6,4,5,7,8,9,2,10,11,12),
(6,4,5,7,8,9,2,10,11,13),
(6,4,5,7,8,2,10,11,12),
(6,4,5,7,8,2,10,11,13),
(6,4,5,7,8,9,2,3),
(6,4,8,9,2,3),
(7,8,9,2,3,4,5,7),
(7,8,2,3,4,5,7),
(8,9,2,3,4,5,7,8),
(8,2,3,4,5,7,8),
(8,9,2,3,4,8),
(8,2,3,4,8),
(9,2,3,4,5,7,8,9),
(9,2,3,4,8,9),
(11,12,11),
(12,11,12),
(12,11,13)
}
问题5:基于Junit及Eclemma( jacoco)实现一个主路径覆盖的测试。
可以用上次实验一的三角形程序进行主路径覆盖测试。
考虑等边三角形,等腰三角形,不等边三角形和不能组成三角形这四种情况,覆盖率达到了100%。