一、PowerMock简介
Mockito框架虽然解除了外部资源的依赖，能提高测试用例的运行速度和效率，但是仍然有自己的局限性，比如不能对final、private、static方法进行mock。PowerMock是在其他Mock框架的基础上做了扩展，解决了它们的局限性，实现了额外的功能。
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二、PowerMock环境设置
在应用PowerMock之前需要在build.gradle文件中添加相应的依赖：
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三、PowerMock的使用
| PowerMock的使用步骤 |
| ① 在测试类的class xxTest{}上增加两行注解： @RunWith(PowerMockRunner.class) @PrepareForTest({ mock对象.class }) ②?创建mock对象，并对mock对象进行打桩设置返回值； ③?创建被测试类，并调用测试的方法； ④?对真实值和期盼值进行assert验证。 |
1、PowerMock mock?静态方法
???????假如有以下被测试类BusinessService和工具类BusinessUtil：
| public class BusinessService { ?????? public List<String> getAllUser() { ????????????? return BusinessUtil.getAllUser(); ?????? } ?????? } |
| public class BusinessUtil { ?????? public?static?List<String> getAllUser() { ????????????? return Arrays.asList("zhangsan", "lisi"); ?????? } ?????? } |
可见，被测试类BusinessService需要用到BusinessUtil里的静态方法getAllUser()，因此可以对静态方法进行PowerMock，即
| import java.util.Arrays; import java.util.List; import org.junit.Assert; import org.junit.Test; import org.junit.runner.RunWith; import org.mockito.Mockito; import org.powermock.api.mockito.PowerMockito; import org.powermock.core.classloader.annotations.PrepareForTest; import org.powermock.modules.junit4.PowerMockRunner; @RunWith(PowerMockRunner.class) @PrepareForTest({ BusinessUtil.class }) public class BusinessServiceTest { ?????? @Test ?????? public void test() { ????????????? List<String> expected = Arrays.asList("test", "test2"); ??????????????// Mock?静态方法 ??????????????PowerMockito.mockStatic(BusinessUtil.class); ??????????????Mockito.when(BusinessUtil.getAllUser()).thenReturn(expected); ????????????? //?调用测试方法 ????????????? BusinessService businessService = new BusinessService(); ????????????? List<String> users = businessService.getAllUser(); ??????????????//?验证 ??????????????Assert.assertArrayEquals(expected.toArray(), users.toArray()); ?????? } } |
2、PowerMock mock私有方法
| 被测试类 |
| public class BusinessService { ?????? public List<String> getAllUser() { ??????????????//?调用?private?方法 ????????????? return users(); ?????? } ?????? ?????? private List<String> users() { ????????????? return Arrays.asList("zhangsan", "lisi"); ?????? } ?????? } |
| 测试类 |
| import java.util.Arrays; import java.util.List; import org.junit.Assert; import org.junit.Test; import org.junit.runner.RunWith; import org.powermock.api.mockito.PowerMockito; import org.powermock.core.classloader.annotations.PrepareForTest; import org.powermock.modules.junit4.PowerMockRunner; @RunWith(PowerMockRunner.class) @PrepareForTest({ BusinessService.class }) public class BusinessServiceTest { ?????? @Test ?????? public void test() throws Exception { ????????????? List<String> expected = Arrays.asList("test", "test2"); ??????????????// Mock?私有方法 ??????????????BusinessService businessService = PowerMockito.spy(new BusinessService()); ????????????? PowerMockito.doReturn(expected).when(businessService, "users"); ????????????? //?调用测试方法 ????????????? List<String> users = businessService.getAllUser(); ??????????????//?验证 ??????????????Assert.assertArrayEquals(expected.toArray(), users.toArray()); ?????? } } |
3、PowerMock测试私有方法
| 被测试类 |
| public class BusinessService { ?????? private int max(int a, int b) { ????????????? return a > b ? a : b; ?????? } } |
| 测试类 |
| import org.junit.Assert; import org.junit.Test; import org.junit.runner.RunWith; import org.powermock.core.classloader.annotations.PrepareForTest; import org.powermock.modules.junit4.PowerMockRunner; import org.powermock.reflect.Whitebox; @RunWith(PowerMockRunner.class) @PrepareForTest({ BusinessService.class }) public class BusinessServiceTest { ?????? @Test ?????? public void test() throws Exception { ????????????? BusinessService businessService = new BusinessService(); ??????????????//?调用私有方法 ??????????????int max = Whitebox.invokeMethod(businessService, "max", 1, 2); ??????????????//?验证 ??????????????Assert.assertTrue(2 == max); ?????? } } |