Question

以下是要测试的示例类：

public class TestOuterClass {
  private final InnerClass innerObj;

  boolean status;
  Object nullObj = null;

  public TestOuterClass(boolean status) {
    this.innerObj = new InnerClass();
    this.status = status;
  }

  public class InnerClass {
    public boolean doInner() {
      return outerMethod();
    }
  }

  public void mockOuterMethod() {
    if (innerObj.doInner()) {
      return;
    }
    throw new RuntimeException();
  }

  boolean outerMethod() {
    nullObj.toString();
    return status;
  }
}

以下是示例测试代码：

@RunWith(PowerMockRunner.class)
@PrepareForTest(TestOuterClass.class)
public class TestMockOuterClass {
  @Test
  public void testMockOuterMethod() {
    TestOuterClass outerObj = spy(new TestOuterClass(false));
    doReturn(true).when(outerObj).outerMethod();
    outerObj.mockOuterMethod();
  }

  @Test
  public void testOuterMethod() {
    TestOuterClass outerObj = spy(new TestOuterClass(false));
    doReturn(true).when(outerObj).outerMethod();
    assertTrue(outerObj.outerMethod());
  }
}

请注意，第一个测试失败，并带有以下异常堆栈，第二个测试成功：

java.lang.NullPointerException
at org.apache.samza.runtime.TestOuterClass.outerMethod(TestOuterClass.java:31)
at org.apache.samza.runtime.TestOuterClass$InnerClass.doInner(TestOuterClass.java:19)
at org.apache.samza.runtime.TestOuterClass.mockOuterMethod(TestOuterClass.java:24)
at org.apache.samza.runtime.TestMockOuterClass.testMockOuterMethod(TestMockOuterClass.java:22)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:68)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:316)
at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:89)
at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:97)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.executeTest(PowerMockJUnit44RunnerDelegateImpl.java:300)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTestInSuper(PowerMockJUnit47RunnerDelegateImpl.java:131)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.access$100(PowerMockJUnit47RunnerDelegateImpl.java:59)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner$TestExecutorStatement.evaluate(PowerMockJUnit47RunnerDelegateImpl.java:147)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.evaluateStatement(PowerMockJUnit47RunnerDelegateImpl.java:107)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit47RunnerDelegateImpl$PowerMockJUnit47MethodRunner.executeTest(PowerMockJUnit47RunnerDelegateImpl.java:82)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$PowerMockJUnit44MethodRunner.runBeforesThenTestThenAfters(PowerMockJUnit44RunnerDelegateImpl.java:288)
at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:87)
at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:50)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.invokeTestMethod(PowerMockJUnit44RunnerDelegateImpl.java:208)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:147)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:121)
at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:123)
at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:121)
at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:53)
at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

当我为类TestOuterClass创建一个间谍对象并直接模拟并测试outerMethod时，它似乎起作用了。但是，从outerMethod方法触发InnerClass.doInner()时，模拟无法正常工作。建议修复第一个测试的方法是什么？

Answer 1

让我们逐点讲解此示例。

在测试案例中，您围绕TestOuterClass的实例创建了一个间谍。在创建实例时（在构造函数中），您将创建InnerClass对象作为其字段。

现在，您可以模拟outerMethod的行为以使其始终返回true。

现在，调用outerObj.mockOuterMethod()时会发生的是正在调用 real 方法，因为它没有被模拟。您可以在提供的堆栈跟踪中看到它：

at org.apache.samza.runtime.TestOuterClass.outerMethod(TestOuterClass.java:31)
at org.apache.samza.runtime.TestOuterClass$InnerClass.doInner(TestOuterClass.java:19)
at org.apache.samza.runtime.TestOuterClass.mockOuterMethod(TestOuterClass.java:24)

稍后，它只是继续调用真实的doInner方法-此处可能会令人困惑-真实的outerMethod。

您可能会说：“嘿，我嘲笑那件事”。但是您会看到-通过这种方法：

public boolean doInner() {
  return outerMethod();
}

您实际上是在指this.outherMethod()。问题是，从InnerClass的角度来看，this指的是实际的TestOuterClass实例-不是间谍。

创建实例的间谍时，正在创建一种代理。当您调用一个被模拟的方法时，那么甚至都不会达到真实的对象。但是，当您调用未模拟的方法时，它将“代理”对实际对象的调用。

所以您的问题是：如何解决？

您可以添加另一个TestOuterClass构造函数，而不是创建InnerClass实例，而是将其注入：

public TestOuterClass(boolean status, InnerClass innerObj) {
    this.innerObj = innerObj;
    this.status = status;
}

然后，您可以在测试中创建将InnerClass的模拟传递给构造函数：

TestOuterClass.InnerClass innerObjMock = Mockito.mock(TestOuterClass.InnerClass.class);
TestOuterClass outerObj = spy(new TestOuterClass(false, innerObjMock));

通过此设置，您可以模拟innerObjMock的行为。

如果这不是您想要的东西，请告诉我。

内部类无法访问模拟的外部类方法

1 个答案: