前言
這篇文章介紹如何使用Springboot+Junit+Mockito做單元測試,案例選取撮合交易的一個類來做單元測試。
單元測試前先理解需求
要寫出好的單測,必須先理解了需求,只有知道做什麼才能知道怎麼測。但本文主要講mockito的用法,無需關注具體需求。所以本節略去具體的需求描述。
隔離外部依賴
Case1. 被測類中被@Autowired 或@Resource 註解標註的依賴對象,如何控制其返回值
以被測方法MatchingServiceImpl.java的matching(MatchingOrder buyOrder, MatchingOrder sellOrder)為例
被測類MatchingServiceImpl
public class MatchingServiceImpl implements MatchingService { private static final Logger log = LoggerFactory.getLogger(MatchingServiceImpl.class); @Autowired private QuoteService quoteService; ... public MatchingResult matching(MatchingOrder buyOrder, MatchingOrder sellOrder) { int currentPrice = quoteService.getCurrentPriceByProduct(buyOrder.getProductCode()); MatchingResult result = new MatchingResult(); if (sellOrder != null && buyOrder != null && sellOrder.getPrice() <= buyOrder.getPrice()) { ... }}matching方法中的quoteService.getCurrentPriceByProduct(buyOrder.getProductCode());要訪問Redis獲取當前報價,這裡我們需要把外部依賴quoteService mock掉,控制getCurrentPriceByProduct方法的返回值。使用mockito可以做到,具體如下:
測試類MatchingServiceImplTest
public class MatchingServiceImplTest extends MockitoBasedTest { /** * 被@Mock標註的對象會自動注入到被@InjectMocks標註的對像中*/ @Mock private QuoteService quoteService; /** * <pre> * 被測對象,用@InjectMocks標註,那些被@mock標註的對象就會自動注入其中。 * 另一個注意點是這裡的MatchingServiceImpl是直接new出來(Mockito 1.9版本後不new也可以),而不是通過spring容器注入的。因為這裡我不需要從spring容器中* 獲得其他依賴,不需要database ,redis ,zookeeper,mq,啥都不依賴,所以直接new * </pre> */ @InjectMocks private MatchingServiceImpl matchingService = new MatchingServiceImpl(); @Test public void testMatching_SuccessWhenCurrentPriceBetweenBuyPriceAndSellPrice() { MatchingOrder buyOrder = new MatchingOrder(); buyOrder.setPrice(1000); buyOrder.setCount(23); MatchingOrder sellOrder = new MatchingOrder(); sellOrder.setPrice(800); sellOrder.setCount(20); // 方法打樁(Method stubbing) // when(x).thenReturn(y) :當指定方法被調用時返回指定值Mockito.when(quoteService.getCurrentPriceByProduct(Mockito.anyString())).thenReturn(900); MatchingResult result = matchingService.matching(buyOrder, sellOrder); org.junit.Assert.assertEquals(true, result.isSuccess());// 斷言撮合是否成功org.junit.Assert.assertEquals(20, result.getTradeCount());// 斷言成交數量org.junit.Assert.assertEquals(900, result.getTradePrice()); // 斷言最新報價是否符合預期}Case2. 被測函數A調用被測類其他函數B,怎麼控制函數B的返回值?
比如,MatchingServiceImpl中有個函數startBuyProcess,它裡面調用了該類中的其他函數,如getTopSellOrder,matching,如何控制這兩個函數的返回值?
這裡要解決的問題其實是怎麼對一個類”部分mock”被測類的被測方法(如startBuyProcess)要真實執行,而另一些方法(如getTopSellOrder)則是要打樁(不真正進去執行)。
被測類MatchingServiceImpl
protected void startBuyProcess(MatchingOrder buyOrder, boolean waitForMatching) { while (true) { //對手方最優價MatchingOrder topSellOrder = getTopSellOrder(buyOrder.getProductCode()); MatchingResult matchingResult = matching(buyOrder,topSellOrder); if(matchingResult.isSuccess()) { doMatchingSuccess(buyOrder,topSellOrder,matchingResult,MatchingType.BUY); if(buyOrder.getCount() <= 0) { break; } }else { if(waitForMatching) { //加入待撮合隊列addToMatchingBuy(buyOrder); }else { //撤單sendCancleMsg(buyOrder); } break; } } }利用Mockito.spy()可以做到“部分Mock”
測試類MatchingServiceImplTest.testStartBuyProcess_InCaseOfMatchingSuccess
/** * * 測試StartBuyProcess方法在撮合成功後的處理是否符合預期,即測試startBuyProcess方法進入下面這個判斷分支後的行為* {@link MatchingServiceImpl#startBuyProcess(MatchingOrder, boolean)} * * <pre> * if (matchingResult.isSuccess()) { * * doMatchingSuccess(buyOrder, topSellOrder, matchingResult, MatchingType.BUY); * * if (buyOrder.getCount() <= 0) { * break; * } * } * </pre> * */ @Test public void testStartBuyProcess_InCaseOfMatchingSuccess() { MatchingOrder buyOrder = new MatchingOrder(); buyOrder.setPrice(700); buyOrder.setCount(23); // 用Mockito.spy()對matchingService進行部分打樁matchingService = Mockito.spy(matchingService); MatchingResult firstMatchingResult = new MatchingResult(); firstMatchingResult.setSuccess(true); firstMatchingResult.setTradeCount(20); MatchingResult secondMatchingResult = new MatchingResult(); secondMatchingResult.setSuccess(false); // doReturn(x).when(obj).method() 對方法打樁,打樁後,程序執行這些方法時將按照預期返回指定值,未被打樁的方法將真實執行// 兩個doReturn表示第一次調用matchingService.matching時返回firstMatchingResult,第二次調用返回secondMatchingResult // 因為startBuyProcess裡有個while循壞,可能會多次執行matching方法Mockito.doReturn(firstMatchingResult).doReturn(secondMatchingResult).when(matchingService) .matching(Mockito.any(MatchingOrder.class), Mockito.any(MatchingOrder.class)); MatchingOrder sellOrder = new MatchingOrder(); sellOrder.setPrice(600); sellOrder.setCount(20); // 對getTopSellOrder方法打樁Mockito.doReturn(sellOrder).when(matchingService).getTopSellOrder(Mockito.anyString()); // 對外部依賴jedis的方法進行打樁Mockito.when(jedisClient.incrBy(Mockito.anyString(), Mockito.anyLong())).thenReturn(0L); // startBuyProcess是被測函數,不打樁,會真實執行matchingService.startBuyProcess(buyOrder, true); // 後面的校驗和斷言是測試doMatchingSuccess方法的行為的,這也是這個測試的目的// verify可用來校驗,某個類的方法被執行過多少次,這裡是校驗jedisClient.zremFirst是否被執行過1次Mockito.verify(jedisClient, Mockito.times(1)).zremFirst(Mockito.anyString()); org.junit.Assert.assertEquals(3, buyOrder.getCount()); org.junit.Assert.assertEquals(0, sellOrder.getCount()); } spy的用法已經演示完畢,下面從testStartBuyProcess_InCaseOfMatchingSuccess說下單元測試的“粒度”。
testStartBuyProcess_InCaseOfMatchingSuccess的目的是想測doMatchingSuccess,我們費了很大勁才把前面的一堆準備工作做完,才能去測doMatchingSuccess。
更好的實踐應該是另起測試方法去單獨測doMatchingSuccess,關注點也集中很多,doMatchingSuccess覆蓋完了,再測startBuyProcess其實就只是覆蓋下它本身的判斷分支就行了。覆蓋率照樣達到,而且測試代碼也更容易維護,testStartBuyProcess_InCaseOfMatchingSuccess由於考慮的職責太多,它很容易受到變化的影響,細小的東西改變,可能就會影響它的正常工作。
引入測試框架Maven依賴
<dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope></dependency><dependency> <groupId>org.mockito</groupId> <artifactId>mockito-all</artifactId> <version>1.10.19</version> <scope>test</scope></dependency><dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>4.2.5.RELEASE</version> <scope>test</scope></dependency>
springboot+junit+mockito的上下文構建
MockitoBasedTest
@RunWith(SpringJUnit4ClassRunner.class)@SpringApplicationConfiguration(classes = TestApplication.class)public abstract class MockitoBasedTest { @Before public void setUp() throws Exception { // 初始化測試用例類中由Mockito的註解標註的所有模擬對象MockitoAnnotations.initMocks(this); }}// 其他測試類繼承MockitoBasedTest以上就是本文的全部內容,希望對大家的學習有所幫助,也希望大家多多支持武林網。