PowerMock 测试通过然后失败

Question

为什么我的单元测试在运行独立时通过，但在运行多个测试时失败？

当我执行单个单元测试时，我的测试将成功模拟并 return 预期结果。但是，当我运行所有单元测试时，我之前通过的测试都将失败。

一次测试运行

shouldDoThisAgain() - Pass

多次测试运行秒

shouldDoThis() - Pass

shouldDoThisAgain() - Fail

shouldDoThisAgainAgain() - Fail

我的测试：

@PrepareForTest({OtherMethods.class})
@PowerMockIgnore("javax.management.*")
@RunWith(PowerMockRunner.class)
public class DbTest {
    @Test
    public void shouldDoThis() throws Exception() {
        Dal dalMock = mock(Dal.class)
        PowerMockito.whenNew(Dal.class).withAnyArguments().thenReturn(dalMock)
        List<Result> results = new ArrayList<Result>();
        results.add(new Result(1,2,3));
        when(dalMock.getResults()).thenReturn(results)
        assertTrue(Wrapper.MY_WRAPPER.run()); 
    }
    @Test
    public void shouldDoThisAgain() throws Exception() {
        Dal dalMock = mock(Dal.class)
        PowerMockito.whenNew(Dal.class).withAnyArguments().thenReturn(dalMock)
        List<Result> results = new ArrayList<Result>();
        results.add(new Result(2,3,4));
        when(dalMock.getResults()).thenReturn(results)
        assertTrue(Wrapper.MY_WRAPPER.run());
    }
    @Test
    public void shouldDoThisAgainAgain() throws Exception() {
        Dal dalMock = mock(Dal.class)
        PowerMockito.whenNew(Dal.class).withAnyArguments().thenReturn(dalMock)
        List<Result> results = new ArrayList<Result>();
        results.add(new Result(6,5,3));
        when(dalMock.getResults()).thenReturn(results)
        assertTrue(Wrapper.MY_WRAPPER.run());
    }
}

我的类:

public class Wrapper {
    // not Runnable
    public static final MyWrapper MY_WRAPPER = new MyWrapper(...){
        @Override
        public boolean run() {
           // returns empty list when the test is alone
           // returns 'results' variable when ran with other tests alone
           List<Result> results = OtherMethods.getDal().getResults();
           return !results.isEmpty()
        }
    };  
}

public class OtherMethods {
     private static final Logger LOGGER = LogManager.getLogger(OtherMethods.class);

     public static Dal dal;
     
     static Dal getDal() {
         if (dal == null) {
             try {   
                 dal = new Dal();
             } catch (Exception e) {
               LOGGER.fatal("DB Connection could not be created for Geonames");
               LOGGER.fatal(e);
           }
        }
        return dal;
    }
}

Answer 1

检查 @PrepareForTest({OtherMethods.class}) 放置在 class 水平时的行为...

已删除以回应 OP 的评论
我刚刚注意到其他事情：
我假设你的 MyWrapper class 是 Runnable 因此它只能 run() 一次，你需要为每个测试重新初始化它
已删除

编辑： 那么你的问题出在你的OtherMethodsclass实现上，你没有在这里显示，这给我们造成了困难

Answer 2

尝试这样做

@PrepareForTest({OtherMethods.class})
@PowerMockIgnore("javax.management.*")
@RunWith(MowerMockRunner.class)
public class DbTest {
@Before
public void setUp(){
     Dal dalMock = mock(Dal.class);        
PowerMockito.whenNew(Dal.class).withAnyArguments().thenReturn(dalMock);
List<Result> results = new ArrayList<Result>();
    results.add(new Result(1,2,3));
    when(OtherMethods.getDal().getResults()).thenReturn(results)
}
@Test
public void shouldDoThis() throws Exception() {

    assertTrue(Wrapper.MY_WRAPPER.run());
}
@Test
public void shouldDoThisAgain() throws Exception() {

    assertTrue(Wrapper.MY_WRAPPER.run());
}
@Test
public void shouldDoThisAgainAgain() throws Exception() {

    assertTrue(Wrapper.MY_WRAPPER.run());
}
}

Answer 3

我找到了我们项目的解决方案。我写了一个 Logger class 调用 Android 的内部静态 Log 方法。我的一些测试没有直接测试Log class。当我忽略所有这些时，基于 powermockito 的测试变为绿色。但是当这些其他测试是运行时，基于 powermockito 的测试将失败。有时候。

这种方法会失败（不稳定）：

@RunWith(PowerMockRunner.class)
@PrepareForTest({Log.class})    // WARNING: HERE BE DRAGONS!
public class MyTest {

    @Test
    public void testMethodThatDoesNotUseStatics() {
        // ...
    }

    @Test
    public void usesStatics() {
        // ...
    }

}

然后我发现你可以用@PrepareForTest注释每个测试方法，像这样：

@RunWith(PowerMockRunner.class)
public class MyTest {

    @Test
    public void testMethodThatDoesNotUseStatics() {
        // ...
    }

    @Test
    @PrepareForTest({Log.class})    // that's the way :)
    public void usesStatics() {
        // ...
    }

}

现在测试又变绿了。是的，非易碎测试！ :)

PowerMock 测试通过然后失败

PowerMock test passes then fails

java

unit-testing

mocking

mockito

powermock