问题：

/**
* Finds and prints n prime integers
* Jeff Offutt, Spring 2003
*/


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 primes.

// 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; 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; i++) {
System.out.println("Prime: " + primes[i] );

}

}// End printPrimes.

 

 

(a) Draw the control flow graph for the printPrime() method.
(b) Consider test cases ti = (n = 3) and t2 = ( n = 5). Although these tour the same prime paths in printPrime(), they don't necessarily find the same faults. Design a simple fault that t2 would be more likely to discover than t1 would.
(c) For printPrime(), find a test case such that the corresponding test path visits the edge that connects the beginning of the while statement to the for statement without going through the body of the while loop.
(d) Enumerate the test requirements for node coverage, edge coverage,and prime path coverage for the path for printPrimes().

 

 

回答：

(a).控制流图如下

(b).数组越界即可,当MAXPRIMES == 4时,n=5会引发越界

(c).n= 1时,不满足numPrimes<n,不会遍历while的主体,直接指向13

(d).

点覆盖{1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17}

边覆盖{(1,2),(2,3),(2,13),(3,4),(4,5),(5,6),(5,10),(6,7),(6,8),(7,5),(8,9),(9,10),(10,11),(10,12),(11,12),(12,2),(13,14),(14,15),(14,17),(15,16),(16,14)}

主路径覆盖{(1,2,3,4,5,6,7),(1,2,3,4,5,6,8,9,10,12),(1,2,3,4,5,6,8,9,10,11,12),(1,2,3,4,5,10,11),(1,2,3,4,5,10,12),(1,2,13,14,15,16),(1,2,13,14,17),(3,4,5,6,8,9,10,12,2,13,14,15,16), (3,4,5,6,8,9,10,11,12,2,13,14,15,16),(3,4,5,6,8,9,10,12,2,13,14,17),(3,4,5,6,8,9,10,11,12,2,13,14,17),(3,4,5,9,11,2,12,13,14,15),(3,4,5,9,10,11,2,12,13,14,15),(3,4,5,9,11,2,12,13,16),(3,4,5,10,12,2,13,14,17),(6,7,5,10,12,2,13,14,15,16),(6,7,5,10,11,12,2,13,14,15,16),(6,7,5,10,12,2,13,14,17),(6,7,5,10,11,12,2,13,14,17),(15,16,14,17),(14,15,16,14),(5,6,7,5),(2,3,4,5,6,8,9,10,12,2),(2,3,4,5,6,8,9,10,11,12,2),(2,3,4,5,10,11,12,2)(2,3,4,5,9,10,12,2)}

 

设计主路径覆盖

第一次试验中的三角形已完成完全覆盖

Tri类

package stlab1;

public class Tri {
public static String isTri(double a,double b,double c)
{
if (b >= a && b >= c)
{
double temp = b;
b = a;
a = temp;

}
if (c >= a && c >= b)
{
double temp = c;
c = a;
a = temp;
}
if (b + c <= a)
return "不是三角形";
if (a == b && b == c)
return "等边三角形";
if (a == b || b == c || a == c)
{
return "等腰三角形";
}

if (a * a == b * b + c * c)
return "直角三角形";
return "一般三角形";
}
}

test类

package stlab1;

import static org.junit.Assert.*;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

public class TriTest {

@BeforeClass
public static void setUpBeforeClass() throws Exception {
}

@AfterClass
public static void tearDownAfterClass() throws Exception {
}

@Before
public void setUp() throws Exception {
}

@After
public void tearDown() throws Exception {
}

@Test
public void test() {
Tri tri = new Tri();
assertEquals("等边三角形",tri.isTri(1, 1, 1));
assertEquals("不是三角形",tri.isTri(0, 1, 2));
assertEquals("直角三角形",tri.isTri(3, 4, 5));
assertEquals("等腰三角形",tri.isTri(3, 3, 5));
assertEquals("一般三角形",tri.isTri(4, 6, 7));
assertEquals("等腰三角形",tri.isTri(4, 4, 2));
assertEquals("等腰三角形",tri.isTri(3, 2, 2));

}

}