How do i Test this Exception throwing method?

I have the combination of 2 methods that add objects into a hashset. If the param is null, it throws a NothingToAddException. How can i test this case with Junit5 Tests? I need to get the method tested to 100%

package edu.hm.cs.swe2.products;

import java.util.HashSet;
import java.util.Iterator;

import edu.hm.cs.swe2.exceptions.NothingToAddException;
import edu.hm.cs.swe2.food.Food;

public class Box<T extends Food> extends Product implements Placeable {

	public HashSet<T> content;

	public Box(int serialID, double price, String productName) {
		super(serialID, price, productName);
		this.content = new HashSet<T>();

	}

	@Override
	public int getProductSerial() {
		return this.getSerialID();
	}

	public void addFood(T food) throws NothingToAddException {

		if (food == null) {
			throw new NothingToAddException();
		}
		content.add(food);
	}

	public int addFoods(T... foodsToAdd) {
		int foodsAdded = 0;
		if (foodsToAdd.length > 3) {
			System.out.println("Too much Content. Nothing added.");
		} else {

			for (int i = 0; i < foodsToAdd.length; i++) {
				try {
					this.addFood(foodsToAdd[i]);
					foodsAdded++;
				} catch (NothingToAddException e) {
				}
			}
		}
		return foodsAdded;
	}

this is my testmethod so far where i already tested the usual cases

	@Test
	void addFoodsTest() {
		Box<Cake> testBox = new Box<Cake>(1, 0.50, "testBox");
		Cake cake1 = new Cake(Flavour.CHOCLATE, 20);
		Cake cake2 = new Cake(Flavour.VANILLA, 30);
		Cake cake3 = new Cake(Flavour.STRAWBERRY, 20);
		Cake cake4 = new Cake(Flavour.CHOCLATE, 30);

		assertEquals(1, testBox.addFoods(cake1));
		testBox.addFoods(cake1, cake2, cake3, cake4);

		testBox.addFoods(null);

	}