软件测试学习（4）

    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 (curPrime%primes[i]==0) 
                { // 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

public class Statistics {
    
    /**
     * 
     * @param numbers
     * @return the length of the array
     */
    public int calLength(int[] numbers) {
        int length = numbers.length;
        
        return length;
    }

    /**
     * 
     * @param numbers
     * @return the mean value of the array
     */
    
    public double calMean(int[] numbers) {
        int length = calLength(numbers);
        
        double sum;
        sum = 0.0;
        for (int i = 0; i < length; i++) {
            sum += numbers[i];
        }
        double mean = sum / (double) length;
        
        return mean;
    }

    /**
     * 
     * @param numbers
     * @return the var value of the array
     */
    public double calVar(int[] numbers) {
        int length = calLength(numbers);
        double mean = calMean(numbers);
        
        double varsum = 0.0;
        for (int i = 0; i < length; i++) {
            varsum = varsum + ((numbers[i] - mean) * (numbers[i] - mean));
        }
        double var = varsum / (length - 1.0);
        
        return var;
    }

}

import static org.junit.Assert.*;

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


public class StatisticsTest {
    private Statistics statistics;
    
    @Before
    public void setUp() throws Exception {
        statistics = new Statistics();
    }

    @Test
    public void test() {
        //fail("Not yet implemented");
        int a[] = {1,1,1,1,1,1} ;
        assertEquals(0.0,statistics.calVar(a),0.0001);
    }

}