Eclipse IDE 集成了JUnit开源单元测试框架。如果不借助Eclipse的图形界面工具来生成并运行我们的JUnit测试，该怎么实现呢？

1. 首先需要在类路径下添加JUnit-4.X jar 包。

2. 编写需要测试的方法。

public class Calculator {

private Calculator(){}

public static int add(int x, int y) {
return x + y; // 正确
}

public static int subtract(int x,int y) {
return y - x; // 错误
}

public static int multiply(int x, int y) {
throw new RuntimeException(); // 抛出异常
}

public static int divide(int x, int y) {
return x / y; // divided by 0
}

public static int module(int x , int y) {
for(;;); //死循环
}

}

编写测试类(Test Class)

import static org.junit.Assert.*;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import static org.zjut.junit.Calculator.*;

public class CalculatorTest {

@Before
public void setUp() throws Exception {
System.out.println("Before testing");
}

@After
public void tearDown() throws Exception {
System.out.println("After testing");
}

@Test
public void testAdd() {
assertEquals("add", 3, add(1, 2));
}

@Test
public void testSubtract() {
assertEquals("subtract", 3, subtract(5, 2));
}

@Test
public void testMultiply() {
assertEquals("multiply", 9, multiply(3, 3));
}

@Test(expected = ArithmeticException.class)
public void testDivide() {
divide(3, 0);
}

@Test(timeout=200)
public void testModule() {
module(1, 2);
}

}