Liam的软件测试学习历程（四）：主路径覆盖练习

(a) Draw the control flow graph for the printPrimes() method.

(b) Consider test cases t1 = ( n = 3 ) and t2 = ( n = 5 ).Design a simple fault that t2 would be more likely to discover than t1 would.

When MAXPRIMES is greater than less 5 but greater than 2, t2 would discover the out of bounds fault which t1 would not discover.

(c)Find a test case visits the edge that connects the beginning of the while statement to the for statement without going through they body of the while loop.

When n = 0, it would not go through the while body.

(d)Enumerate the TR for node coverage,edge coverage and prime path coverage for the graph.

NC: TR={1,2,3,4,5,6,7,8,9,10,11,12,13};

EC: TR={(1,2),(2,3),(2,10),(3,4),(4,5),(4,8),(5,6),(5,7),(6,8),(7,4),(8,2),(8,9),(9,2),(10,11),(11,12),(11,13),(12,11)};

PPC: TR={(1,2,3,4,8,9),(1,2,3,4,5,7),(1,2,3,4,5,6,8,9),(1,2,10,11,12),(1,2,10,11,13),(2,3,4,8,9,2),(2,3,4,8,2),(2,3,4,5,7),(2,3,4,5,6,8,9,2),(2,3,4,5,6,8,2),(2,10,11,12),(2,10,11,13),（3,4,5,6,8,9,2,3),(3,4,5,6,8,2,3),(3,4,8,9,2,3),(3,4,8,2,3),(3,4,5,6,8,9,2,10,11,12),(3,4,5,6,8,2,10,11,12),(3,4,5,6,8,9,2,10,11,13),(3,4,5,6,8,2,10,11,13),(3,4,8,9,2,10,11,12),(3,4,8,2,10,11,12),(3,4,8,9,2,10,11,13),(3,4,8,2,10,11,13),(4,5,7,4),(4,5,6,8,9,2,3,4),(4,5,6,8,2,3,4),(4,8,9,2,3,4),(4,8,2,3,4),(5,7,4,5),(5,6,8,9,2,3,4,5),(5,6,8,2,3,4,5),(6,8,9,2,3,4,5,6),(6,8,9,2,3,4,5,6),(6,8,9,2,3,4,5,7),(6,8,2,3,4,5,7),(7,4,5,7),(7,4,8,9,2,3),(7,4,8,2,3),(7,4,5,6,8,9,2,3),(7,4,5,6,8,2,3),(7,4,5,6,8,9,2,10,11,12),(7,4,5,6,8,9,2,10,11,13),(7,4,5,6,8,2,10,11,12),(7,4,5,6,8,2,10,11,13),(7,4,8,9,2,10,11,12),(7,4,8,9,2,10,11,13),(7,4,8,2,10,11,12),(7,4,8,2,10,11,13),(8,2,3,4,8),(8,9,2,3,4,8),(8,2,3,4,5,6,8),(8,9,2,3,4,5,6,8),(9,2,3,4,8,9),(9,2,3,4,5,6,8,9),(11,12,11),(12,11,12),(12,11,13)}.

SubMission：Test a prime path of the method by using JUint and EclEmma.
First add the isDivisable() method and alter the printPrimes() method. Put the output into an int array :

public class Prime {
    private static final int MAXPRIMES = 100;

    /******************************************************* 
     * Finds and prints n prime integers 
     * Jeff Offutt, Spring 2003 
     ******************************************************/ 
    public static int[] 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]); 
        } 
        return primes;
    } // end printPrime
    
    static Boolean isDivisable (int prime,int curPrime){
        Boolean divisable = false;
            int remainder = curPrime % prime;
            if (remainder== 0){
                divisable = true;
            }
        return divisable;
    }
}

Then write the test code as follow:

import static org.junit.Assert.*;

import org.junit.Before;
import org.junit.Test;


public class PrimeTest {
    private static Prime myTest = null;
    private static int[] myPrime = new int[100]; 
    @Before
    public void setUp() throws Exception {
        myTest = new Prime();
        myPrime[0] = 2;
        myPrime[1] = 3;
        myPrime[2] = 5;
        myPrime[3] = 7;
        myPrime[4] = 11;
    }

    @Test
    public void testPrintPrimes() {
        assertArrayEquals(myPrime,myTest.printPrimes(5)); 
    }

}

Test result: