Calculations and Testing

package utils;

public class Calculation {
    public static int findMax(int arr[]){
        int max = 0;
        if(arr != null) {
            for (int i = 0; i < arr.length; i++) {
                if (max < arr[i]) {
                    max = arr[i];
                }
            }
        }
        return max;
    }

    public static int cube(int n){
        if (n > 0) {
            return n * n * n;
        }
        else{
            return 0;
        }
    }

}

//////////////////////////////////////////

package test;

import static org.junit.jupiter.api.Assertions.*;

import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.DisplayName;
import org.junit.jupiter.api.Test;

import utils.Calculation;

class CalculationTests {
    private static int[] value;

    @BeforeAll
    static void setUpBeforeClass() throws Exception {
        value = new int[]{2, -4, -8, 5, 8, 2, 1, 0};
    }

    @Test
    @DisplayName("Test find max providing diff nums")
    void testMax1() {
        assertEquals(8, Calculation.findMax(value));
    }

    @Test
    @DisplayName("Test find max providing null")
    void testMax2() {
        assertEquals(0, Calculation.findMax(null));
    }

    @Test
    @DisplayName("Test cube volume providing 0")
    void testCube1(){
        assertEquals(0, Calculation.cube(0));
    }

    @Test
    @DisplayName("Test cube volume providing positive num")
    void testCube2(){
        assertEquals(27, Calculation.cube(3));
    }

    @Test
    @DisplayName("Test cube volume providing negative num")
    void testCube3(){
        assertEquals(0, Calculation.cube(-4));
    }
}