Software Testing: Please help me write a few Junit test cases for the following code!

Thank you, will upvote immediately for any correct responses!

/******************************************************* Finds and prints n prime integers ********************************************************/

public class PrintPrimes { //Empty Constructor public PrintPrimes(){}

private boolean isDivisible (int i, int j) { if (j%i == 0) return true; else return false; } public int[] printPrimes (int n, boolean showAll) { int curPrime; // Value currently considered for primeness int numPrimes; // Number of primes found so far. boolean isPrime; // Is curPrime prime? int [] primes = new int [100]; // The list of prime number candidates. // 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 (isDivisible (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 // Add prime(s) to final output array (flag dependent). int[] listOfPrimes = new int[numPrimes]; if(showAll){ int count = 0; for (int thisPrime: primes) { if(thisPrime != 0) { // Add primes to final array up to index "numPrimes - 1" listOfPrimes[count++] = thisPrime; } else { break; } } } else { listOfPrimes = new int[1]; listOfPrimes[0] = primes[numPrimes - 1]; } return listOfPrimes; } // end printPrimes }