import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;
import java.util.Random;

public class SolutionTest {
    private static final Random RANDOM = new Random();

    @Test
    public void twoShouldBeAPrime() {
      testPrime(2, true);
    }

    @Test
    public void fourShouldNotBeAPrime() {
      testPrime(4, false);
    }    
    @Test
    public void anyNumberGreaterThanFiveAndEndingWithFiveShouldBeAPrime(){
      testPrime(15, false);    
    }
    
    @Test
    public void aSquareShouldNotAPrime() {
      for (int i = 0; i < 10000; ++i) {
        int randomNumber = RANDOM.nextInt(Short.MAX_VALUE) + 2;
        int numberToCheck = randomNumber * randomNumber;
        testPrime(numberToCheck, false);
      }
    }
    
    @Test
    public void aProductOfTwoIntegersShouldNotBeAPrime() {
      for (int i = 0; i < 100000; ++i) {
        int a = RANDOM.nextInt(Short.MAX_VALUE) + 2;
        int b = RANDOM.nextInt(Short.MAX_VALUE) + 2;
        int numberToCheck = a * b;
        testPrime(numberToCheck, false);
      }
    }
    
    
    
    private static void testPrime(int numberToCheck, boolean expected) {     
      boolean actual = Primes.isAPrime(numberToCheck);
      assertEquals(Integer.toString(numberToCheck), expected, actual);
    }
}