java - PowerMock:模拟具有不同参数的同一方法的多次调用表现异常

Question

我是 Mockito 的新手，遇到一个问题花了我很多时间。以下是我的问题陈述和可执行代码。

问题

每当我尝试从具有不同参数的同一方法模拟多个行为时，mockito/powermockito 会使用我在单个测试中为测试定义的最后一个行为。下面是我的示例，Service 类有一个静态的foo 从我的方法(我想测试)中使用不同参数调用的方法。

它抛出 ClassCastException 并想将 BResponse 转换为 AResponse，因为我最后一次为 BResponse stub 而我在 ClassUnderTest.execute() 中对 foo 的第一次调用要求 AResponse。

示例代码

package poc.staticmethod;

import static org.mockito.Matchers.any;
import static org.powermock.api.mockito.PowerMockito.mockStatic;
import static org.powermock.api.mockito.PowerMockito.when;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.powermock.core.classloader.annotations.PrepareForTest;
import org.powermock.modules.junit4.PowerMockRunner;

import lombok.AllArgsConstructor;
import lombok.Data;

@RunWith(PowerMockRunner.class)
@PrepareForTest(PocStaticTest.Service.class)
public class PocStaticTest {
  

  @InjectMocks
  ClassUnderTest c = new ClassUnderTest();
  
  @Before
  public void beforeTest() throws Exception {
    mockStatic(Service.class);
  }

  @Test
  public void myTest() {
    when(Service.foo(any(), new ARequest(any(), "A"))).thenReturn(new AResponse(1, "passed"));
    when(Service.foo(any(), new ARequest(any(), "2A")))
        .thenReturn(new AResponse(2, "passed"));
    when(Service.foo(any(), new BRequest(any(), "B")))
        .thenReturn(new BResponse(112, "passed"));
    
    c.execute();
  }

  public class ClassUnderTest {
    public void execute() {
      AResponse ar = (AResponse) Service.foo("A1", new ARequest(1, "A"));
      AResponse ar2 = (AResponse) Service.foo("A2", new ARequest(2, "2A"));
      BResponse br = (BResponse) Service.foo("B1", new BRequest(1, "B"));
    }
  }
  
  public static class Service {
    public static Object foo(String firstArgument, Object obj) {
      return null;
    }
  }
  
  @Data
  @AllArgsConstructor
  public class ARequest {
    public Integer num;
    public String name;
  }

  @Data
  @AllArgsConstructor
  public class AResponse {
    public Integer error;
    public String message;
  }

  @Data
  @AllArgsConstructor
  public class BRequest {
    public Integer num;
    public String name;
  }

  @Data
  @AllArgsConstructor
  public class BResponse {
    public Integer error;
    public String message;
  }

}

异常:

java.lang.ClassCastException: poc.staticmethod.PocStaticTest$BResponse cannot be cast to poc.staticmethod.PocStaticTest$AResponse
    at poc.staticmethod.PocStaticTest$ClassUnderTest.execute(PocStaticTest.java:44)
    at poc.staticmethod.PocStaticTest.myTest(PocStaticTest.java:39)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:68)
    at org.powermock.modules.junit4.internal.impl.PowerMockJUnit44RunnerDelegateImpl$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.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)  

Answer 1

为您的自定义对象使用 eq() 匹配器，通过此更改您的函数模拟将看起来像链接:

when(Service.foo(any(), eq(new ARequest(1, "A")))).thenReturn(new AResponse(1, "passed"));
when(Service.foo(any(), eq(new ARequest(2, "2A")))).thenReturn(new AResponse(2, "passed"));
when(Service.foo(any(), eq(new BRequest(1, "B")))).thenReturn(new BResponse(112, "passed"));

您应该在 Request 对象中指定参数并从内部删除 any()。

另一种选择是写下您的答案并检查其中的类型，例如:

when(mock.foo(anyString(), anyObject())).thenAnswer(
    invocation -> {
        Object argument = invocation.getArguments()[1];
        if (argument.equals(new ARequest(1, "A"))) {
            return new AResponse(1, "passed");
        } else if (argument.equals(new ARequest(2, "2A"))) {
            return new AResponse(2, "passed");
        } else if (argument.equals(new BRequest(1, "B"))) {
            return new BResponse(112, "passed");
        }
        throw new InvalidUseOfMatchersException(
            String.format("Argument %s does not match", argument)
        );
    }
);