JUnit basic annotation

一个标准的Junit 4的运行流程，大致如下：
测试类实例化 -> @BeforeClass -> @Before -> @Test -> @After -> @AfterClass

下面的代码输出明确表明了其运行流程：

package com.junit.tutorial; 

import org.junit.*;
import static org.junit.Assert.*;
import java.util.*; 

/**
* @author mkyong
*
*/
public class BasicAnnotation { 

private Collection collection; 

@BeforeClass
public static void oneTimeSetUp() {
// one-time initialization code
System.out.println("@BeforeClass - oneTimeSetUp");
} 

@AfterClass
public static void oneTimeTearDown() {
// one-time cleanup code
System.out.println("@AfterClass - oneTimeTearDown");
} 

@Before
public void setUp() {
collection = new ArrayList();
System.out.println("@Before - setUp");
} 

@After
public void tearDown() {
collection.clear();
System.out.println("@After - tearDown");
} 

@Test
public void testEmptyCollection() {
assertTrue(collection.isEmpty());
System.out.println("@Test - testEmptyCollection");
} 

@Test
public void testOneItemCollection() {
collection.add("itemA");
assertEquals(1, collection.size());
System.out.println("@Test - testOneItemCollection");
}
} 

结果：
@BeforeClass - oneTimeSetUp
@Before - setUp
@Test - testOneItemCollection
@After - tearDown
@Before - setUp
@Test - testEmptyCollection
@After - tearDown
@AfterClass - oneTimeTearDown

需要注意的是，我们需要申明 @BeforeClass 和 @AfterClass 为静态方法。