// src/main/java/com/example/App.java

package com.example;

// src/main/java/com/example/Calculator.java

calculator/ ├── pom.xml └── src ├── main │ └── java │ └── com │ └── example │ └── App.java └── test └── java └── com └── example └── AppTest.java Let's add a feature to our calculator application that allows it to perform addition, subtraction, multiplication, and division. 3.1 Create a Calculator Class Create a new Java class Calculator.java in src/main/java/com/example :

// src/test/java/com/example/CalculatorTest.java

public double divide(double a, double b) { if (b == 0) { throw new ArithmeticException("Cannot divide by zero"); } return a / b; } } Modify App.java to use the Calculator class:

public class CalculatorTest {

@Test void testDivide() { assertEquals(2, calculator.divide(10, 5), "Division failed"); }