Question

每当为该类创建新对象时，我都需要模拟一个类对象。我没有使用任何Java框架进行依赖项注入。下面是我的代码。

Addition.java

public int sum(int a, int b) {
    return a + b;
}

Application.java

public int doOperation(int a, int b) {
    Addition addition = new Addition();
    return addition.sum(a, b);
}

ApplicationTest.java

@RunWith(PowerMockRunner.class)
@PrepareForTest(Addition.class)

        Addition addition = PowerMockito.mock(Addition.class);
        PowerMockito.when(addition.sum(ArgumentMatchers.anyInt(), ArgumentMatchers.anyInt())).thenReturn(15);

        PowerMockito.whenNew(Addition.class).withNoArguments().thenReturn(addition);

        Application applicationMock = PowerMockito.mock(Application.class);
        int res = applicationMock.doOperation(1, 5);

        assertEquals(res, 15);

在Application.java中，我正在创建Addition类实例。我需要返回一个模拟对象而不是一个新对象。运行我的应用程序时，我得到0为res。

java.lang.AssertionError: 
Expected :0
Actual   :15
<Click to see difference>


    at org.junit.Assert.fail(Assert.java:88)
    at org.junit.Assert.failNotEquals(Assert.java:834)
    at org.junit.Assert.assertEquals(Assert.java:645)
    at org.junit.Assert.assertEquals(Assert.java:631)
    at com.dbs.poc.PowerMockAdditionTest.sumWithMocks(PowerMockAdditionTest.java:38)
    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:326)
    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:310)
    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:298)
    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:218)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.runMethods(PowerMockJUnit44RunnerDelegateImpl.java:160)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$1.run(PowerMockJUnit44RunnerDelegateImpl.java:134)
    at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:34)
    at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:44)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl.run(PowerMockJUnit44RunnerDelegateImpl.java:136)
    at org.powermock.modules.junit4.common.internal.impl.JUnit4TestSuiteChunkerImpl.run(JUnit4TestSuiteChunkerImpl.java:117)
    at org.powermock.modules.junit4.common.internal.impl.AbstractCommonPowerMockRunner.run(AbstractCommonPowerMockRunner.java:57)
    at org.powermock.modules.junit4.PowerMockRunner.run(PowerMockRunner.java:59)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

Answer 1

您缺少一行。试试这个。

 Application applicationMock = PowerMockito.mock(Application.class);
 PowerMockito.when(applicationMock.doOperation(anyInt(), anyInt())).thenCallRealMethod();
 int res = applicationMock.doOperation(1, 5);

您已宣布申请为模拟人。并且未定义doOperation方法的行为。因此，控件不会进入该方法，因此没有任何效果。

这是完整的代码，

@RunWith(PowerMockRunner.class)
@PrepareForTest({Application.class})
public class ApplicationTest {

    @Test
    public void test() throws Exception {
        Addition addition = PowerMockito.mock(Addition.class);
        PowerMockito.when(addition.sum(ArgumentMatchers.anyInt(), ArgumentMatchers.anyInt())).thenReturn(15);

    PowerMockito.whenNew(Addition.class).withNoArguments().thenReturn(addition);

        Application applicationMock = PowerMockito.mock(Application.class);
        when(applicationMock.doOperation(anyInt(), anyInt())).thenCallRealMethod();
        int res = applicationMock.doOperation(1, 5);

        assertEquals(res, 15);
    }
}

如果您只想测试加法。您不需要模拟Application类。而是创建Application类的新实例。这样，您就不需要修复程序，那么您当前的代码就足够了。

使用

Application application = new Application();

代替

Application applicationMock = PowerMockito.mock(Application.class);

如果您有充分的理由使用模拟而不是真实实例，那么这就是解决方案。

Answer 2

这是问题/缺少链接：

Application applicationMock = PowerMockito.mock(Application.class);
int res = applicationMock.doOperation(1, 5);

applicationMock.doOperation(x, y)是什么？ -无，返回0。（您可以配置（Power）mock（ito）引发异常->“严格模拟”）

您想要的是：

a）要测试“真实的Application”（不模拟）：

Application testApp = new Applicaiton();
int res = testApp.doOperation(1, 5);
// ...

或者b）“编写”您的模拟程序，以伪造/复制真实的实现（例如，如@pvpkiran所述）：

Application applicationMock = PowerMockito.mock(Application.class);
PowerMockito.when(applicationMock.doOperation(anyInt(), anyInt())).then...

使用Mockito模拟新对象的创建

2 个答案: