在Java程序的单元测试中常用的mock工具有Mockito和EasyMock。但是这两种mock工具都无法实现对静态、final、私有方法或类的mock。因此有了功能强大的PowerMock工具。PowerMock并不是一个独立、全新的工具而是在Mockito和EasyMock的基础上进行的扩展，它分别有针对Mockito级EasyMock的扩展实现。本文主要介绍PowerMock的常见用法：
1.pom依赖
<dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.10<version> <scope>test</scope> </dependency> <dependency> <groupId>org.powermock</groupId> <artifactId>powermock-module-junit4</artifactId> <version>1.6.3</version> <scope>test</scope> </dependency> <dependency> <groupId>org.powermock</groupId> <artifactId>powermock-api-mockito</artifactId> <version>1.6.3</version> <scope>test</scope> </dependency> |
2.基本用法
2.1 测试类加上必要的注解
@RunWith(PowerMockRunner.class) @PrepareForTest({ExtensionLoader.class,Configs.class}) //静态类，测试类本身（需要mock构造方法时） @PowerMockIgnore("javax.management.*") |
2.2 mock基本对象
测试 convert.convertAndHanlder(method,ref,bead)方法 @Mock Convert convert; when(convert.convertAndHanlder(eq(method),eq(ref),eq(bead))).thenReturn(bead); |
2.3 mock无返回值的方法
@Mock ProviderComposeConfig providerComposeConfig; doNothing().when(providerComposeConfig).putSync(eq(providerConfig)); |
2.4 mock方法执行异常场景
@Mock ProviderComposeConfig providerComposeConfig; doThrow(new Exception("执行失败")).when(providerComposeConfig).putSync(eq(providerConfig)); |
2.5 mock 静态方法
测试Configs.getConfig（ProviderComposeConfig.class）方法 前提：@PrepareForTest注解中添加该类：ProviderComposeConfig.class @Mock ProviderComposeConfig configs; PowerMockito.mockStatic(Configs.class); when(Configs.getConfig(eq(ProviderComposeConfig.class))).thenReturn(configs); mock无返回值的static方法 // "xxxUtil" 是类名 // "xxxStaticMethod" 是 static 方法的方法名 // 这里假设 "xxxStaticMethod" 需要两个参数，一个是 int 型，一个是 String 型 PowerMockito.doNothing().when(xxxUtil.class, "xxxStaticMethod", 1，"mysql"); mock可变参数传递 public class Demo { public static void test(String... args) { System.out.println(args); } } |
测试方法：
@RunWith(PowerMockRunner.class) @PrepareForTest({Demo.class}) @PowerMockIgnore("javax.management.*") public class DemoTest { @Test public void test() throws Exception { PowerMockito.mockStatic(Demo.class); PowerMockito.doNothing().when(Demo.class,"test",eq("liu1"),eq("liu2")); Demo.test("liu1","liu2"); } } |
2.6 mock 构造方法
前提：@PrepareForTest注解中添加该类：HookContext.class
@Mock HookContext context; //无参构造 PowerMockito.whenNew(HookContext.class).withNoArguments().thenReturn(context); //有参构造 PowerMockito.whenNew(HookContext.class).withArguments(anystring()).thenReturn(context); ③完成实例 被测试类： public class HandlerHook { public final static String id = "handler"; @Override public Bead doCall(HookContext context, Bead bead, AccessId id) throws Throwable { ProviderComposeConfig configs = Configs.getConfig(ProviderComposeConfig.class); ProviderConfig config = configs == null ? null : configs.get(id); if (config == null) { // 即没有该服务，1.本地调用 2.客户端信息有误，访问IP:PORT 却没有服务 return null; } // 拿到转换器，调用 Convert convert = ExtensionLoader.getExtensionLoader(Convert.class).getExtensionById(ConvertProcessor.id); return convert.convertAndHanlder(config.getMethod(), config.getRef(), bead); } } |
测试类：
@RunWith(PowerMockRunner.class) @PrepareForTest({ExtensionLoader.class,Configs.class}) @PowerMockIgnore("javax.management.*") public class HandlerHookTest { @Mock HookContext hookContext; @Mock Bead bead; @Mock AccessId accessId; @Mock ExtensionLoader<Convert> extensionLoader; @Mock ProviderComposeConfig configs; @Mock ProviderConfig config; @Mock Method method ; @Mock Object ref; @Mock Convert convert; private HandlerHook handlerHook = new HandlerHook(); @Test public void doCall() throws Throwable { PowerMockito.mockStatic(Configs.class); when(Configs.getConfig(eq(ProviderComposeConfig.class))).thenReturn(configs); when(configs.get(eq(accessId))).thenReturn(config); PowerMockito.mockStatic(ExtensionLoader.class); when(ExtensionLoader.getExtensionLoader(eq(Convert.class))).thenReturn(extensionLoader); when(extensionLoader.getExtensionById(eq("map"))).thenReturn(convert); when(config.getMethod()).thenReturn(method); when(config.getRef()).thenReturn(ref); when(convert.convertAndHanlder(eq(method),eq(ref),eq(bead))).thenReturn(bead); assertEquals(bead, handlerHook.doCall(hookContext, bead, accessId)); } } |
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