Page 63-64 Exercises 2.3.7 -------Introduction to Software Testing (Paul Ammann and Jeff Offutt)

Use the following method printPrimes() for question a-d below

//Find and prints n prime integers

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++;
        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;
            }
        }
        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) Draw the control flow grah for the printPrimes() method.

(b) Consider test cases t1 = (n=3) and t2 = (n=5). Although these tour the same prime paths in printPrimes(), they do necessarily find the same faults. Design a simple fault that t2 would be more likely to discover than t1 would.

　　Ans: the variable "MAXPRIMES" is not known, so we can make "MAXPRIMES = 4". Then t2 would be more likely to discover than t1 would.

(c) For printPrimes(), find a test case such that the corresponding test path visit the edge that connects the beginning of the while statement to the for statement without going through the body of the while loop.

　　Ans: when n = 1, the test case will not go through the body of the while loop.

(d) Enumerate the test requirements for node coverage, edge coverage, and prime path coverage for hte graph for printPrimes().

　　Ans:

　　(i) node coverage: {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14}

　　(ii) edge coverage: {(1, 2), (2, 3), (3, 4), (3, 12), (4, 5), (5, 6), (6, 7), (6, 10), (7, 8), (7, 9), (8, 6), (9, 10), (10, 11), (10, 3), (11, 3), (12, 13), (12, 14), (13, 12)}

　　(iii) prime path: {

　　　　[1, 2, 3, 12, 14],

　　　　[1, 2, 3, 4, 5, 6, 7, 8],

　　　　[1, 2, 3, 4, 5, 6, 10, 11],

　　　　[1, 2, 3, 4, 5, 6, 7, 9, 10 ,11],

　　　　[3, 4, 5, 6, 10, 11, 3],

　　　　[3, 4, 5, 6, 7, 9, 10, 11, 3],

　　　　[3, 4, 5, 6, 7, 9, 10, 3],

　　　　[3, 4, 5, 6, 7, 9, 10, 11, 3],

　　　　[4, 5, 6, 10, 3, 12, 13],

　　　　[4, 5, 6, 10, 11, 3, 12, 13],

　　　　[4, 5, 6, 7, 9, 10, 3, 12, 13],

　　　　[4, 5, 6, 7, 9, 10, 11, 3, 12, 13],　　

　　　　[4, 5, 6, 10, 3, 12, 14],

　　　　[4, 5, 6, 10, 11, 3, 12, 14],

　　　　[4, 5, 6, 7, 9, 10, 3, 12, 14],

　　　　[4, 5, 6, 7, 9, 10, 11, 3, 12, 14],

　　　　[5, 6, 10, 3, 4, 5],

　　　　[5, 6, 10, 11, 3, 4, 5],

　　　　[5, 6, 7, 9, 10, 3, 4, 5],

　　　　[5, 6, 7, 9, 10, 11, 3, 4, 5],

　　　　[6, 7, 8, 6],

　　　　[7, 8, 6, 10, 3, 12, 13],

　　　　[7, 8, 6, 10, 3, 12, 14],

　　　　[7, 8, 6, 10, 11, 3, 12, 13],

　　　　[7, 8, 6, 10, 11, 3, 12, 14],

　　　　[7, 8, 6, 10, 3, 4, 5, 6, 7],

　　　　[7, 8, 6, 10, 11, 3, 4, 5, 6, 7],

　　　　[8, 6, 10, 3, 12, 13],

　　　　[8, 6, 10, 3, 12, 14],

　　　　[8, 6, 10, 11, 3, 12, 13],

　　　　[8, 6, 10, 11, 3, 12, 14],

　　　　[8, 6, 7, 9, 10, 3, 12, 13],

　　　　[8, 6, 7, 9, 10, 3, 12, 14],

　　　　[8, 6, 10, 3, 4, 5, 6, 7, 8],

　　　　[9, 10, 3, 4, 5, 6, 7, 9],

　　　　[10, 11, 3, 4, 5, 6, 7, 9, 10],

　　　　[10, 11, 3, 4, 5, 6, 10],

　　　　[10, 3, 4, 5, 6, 7, 9, 10],

　　　　[10, 3, 4, 5, 6, 10],

　　　　[11, 3, 4, 5, 6, 7, 9, 10, 11],

　　　　[11, 3, 4, 5, 6, 10, 11],

　　　　[12, 13, 12],

　　　　[13, 12, 13]

　　　　}

(e) 基于junit及Eclemma(jacoco)实现一个主路径覆盖的测试。

　被测试代码与测试代码：

package cn.tju;
public class Prime{
    private static int MAXPRIMES = 10;
    public static boolean 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++;
            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;
                }
            }
            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]);
        }
        return true;
    }//end printPrimes
    public static boolean isDivisible(int a, int b){
        return (b%a == 0);
    }
}

package junit;
import static org.junit.Assert.*;
import org.junit.Test;
import cn.tju.Prime;
public class Testing {

    @Test
    public void test() {
        org.junit.Assert.assertEquals(true, new Prime().printPrimes(1));
        org.junit.Assert.assertEquals(true, new Prime().printPrimes(10));
    }

}

结果：