java.lang.NoClassDefFoundError: org/mockito/Mockito at edu.ncsu.csc326.coffeemaker.CoffeeMakerTest.setUp(CoffeeMakerTest.java:76)

Question

package edu.ncsu.csc326.coffeemaker;

public interface RecipeBook {
    
    public Recipe[] getRecipes();
    
    public boolean addRecipe(Recipe r);
    
    public String deleteRecipe(int recipeToDelete);     
    
    public String editRecipe(int recipeToEdit, Recipe newRecipe);

}

package edu.ncsu.csc326.coffeemaker;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.mockito.Mockito.*;

import org.junit.Before;
import org.junit.Test;

import edu.ncsu.csc326.coffeemaker.exceptions.RecipeException;

public class CoffeeMakerTest {

        private Recipe recipe1;
    private Recipe recipe2;
    private Recipe recipe3;
    private Recipe recipe4;
    private Recipe recipe5;
    
    private Recipe [] stubRecipies; 
    private CoffeeMaker coffeeMaker;
        private RecipeBook recipeBookStub;


    @Before
    public void setUp() throws RecipeException {
        
        recipeBookStub = mock(RecipeBook.class); //Getting error for this line of code
        coffeeMaker = new CoffeeMaker(recipeBookStub, new Inventory());
        
        //Set up for recipe1
        recipe1 = new Recipe();
        recipe1.setName("Coffee");
        recipe1.setAmtChocolate("0");
        recipe1.setAmtCoffee("3");
        recipe1.setAmtMilk("1");
        recipe1.setAmtSugar("1");
        recipe1.setPrice("50");
        
        //Set up for recipe2
        recipe2 = new Recipe();
        recipe2.setName("Mocha");
        recipe2.setAmtChocolate("20");
        recipe2.setAmtCoffee("3");
        recipe2.setAmtMilk("1");
        recipe2.setAmtSugar("1");
        recipe2.setPrice("75");

        stubRecipies = new Recipe [] {recipe1, recipe2, recipe3};
    }
    @Test
    public void testMakeCoffee() {
        
        when(recipeBookStub.getRecipes()).thenReturn(stubRecipies);
        coffeeMaker.addRecipe(stubRecipies[0]);
        assertEquals(10,coffeeMaker.makeCoffee(0, 40));
    
    }
}

I am following Coursera course in Testing. This is code snippet from CoffeeMakerTest assignment and I need to write test case with help of mockito. The problem is whenever I run my testing class, the mock function which is supposed to give a object for RecipeBook is giving arror of ClassDefNotFound. This is my first time trying to learn testing so I have not much idea about solution. Coursera had provided the project(used Gradle), I am only supposed to run test with mockito and JUnit.