使用PowerMock进行每次测试后，模拟行为都会重置

我正在使用PowerMock编写unit testing，模拟一些util类的行为。 为测试类定义一次行为（通过@BeforeClass注释）会导致：

• 第一次测试调用返回模拟值
• 第二次测试调用返回实际方法返回值

示例代码：

import org.junit.Assert; import org.junit.BeforeClass; 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( {A.class, B.class}) public class TestMockedMethods { private static B b; @BeforeClass public static void setUp() { PowerMockito.mockStatic(A.class); PowerMockito.when(A.getVal()).thenReturn("X"); b = PowerMockito.mock(B.class); PowerMockito.when(b.getVal()).thenReturn("Y"); } @Test public void test1() { // PASS Assert.assertEquals("X", A.getVal()); Assert.assertEquals("Y", b.getVal()); } @Test public void test2() { // FAIL Assert.assertEquals("X", A.getVal()); // actual="A" Assert.assertEquals("Y", b.getVal()); // actual="B" } } class A { static String getVal() { return "A"; } } class B { String getVal() { return "B"; } } 

任何想法为什么第二次测试失败？

Answer 1

方法PowerMockito.mockStatic(...)调用MockCreator.mock(...) 。 此方法注册了将在每次测试后执行的Runnable：

 MockRepository.addAfterMethodRunner(new MockitoStateCleaner()); 

这个runnable清理了Mockito的内部状态 ：

 private static class MockitoStateCleaner implements Runnable { public void run() { clearMockProgress(); clearConfiguration(); } private void clearMockProgress() { clearThreadLocalIn(ThreadSafeMockingProgress.class); } private void clearConfiguration() { clearThreadLocalIn(GlobalConfiguration.class); } private void clearThreadLocalIn(Class cls) { Whitebox.getInternalState(cls, ThreadLocal.class).set(null); final Class clazz = ClassLoaderUtil.loadClass(cls, ClassLoader.getSystemClassLoader()); Whitebox.getInternalState(clazz, ThreadLocal.class).set(null); } } 

所以你应该在每次测试之前执行你的setUp。

 @Before public void setUp() { PowerMockito.mockStatic(A.class); PowerMockito.when(A.getVal()).thenReturn("X"); b = PowerMockito.mock(B.class); PowerMockito.when(b.getVal()).thenReturn("Y"); }