How to write Junit test case array matrix addition and multiplication?

Question

package testMatrix;

public class MatrixAdd {
    public int [][] addtionOfArray(int [][] numbers){
        int length = numbers.length;
        int output[][] = new int[length][length];
        for(int i=0; i< length; i++){
            for(int j=0; i< length; j++){
                output[i][j] = numbers[i][j] + numbers[i][j];
            }
        }
        return output;
    }
}

How to write Junit test for array matrix addition? and also Junit test for matrix multiplication

Answer 1

in the test source set you can use something similar

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;

public class MatrixAddTest {

    private MatrixAdd testee = MatrixAdd();

    @Test
    public void testAdditionOfArray(){
        int[][] expected = new int[][]{new int[]{2, 0}, new int[]{0, 2}};
        int[][] actual = testee.addtionOfArray(new int[][]{new int[]{1, 0}, new int[]{0, 1}});
        Assertions.assertEquals(expected, actual);
    }
}

however, since MatrixAdd seems like a Utility class, you could also make the methods static, you don't really need a MatrixAdd instance anywhere.