java - Mockito.eq 匹配器似乎匹配列表引用，而不是值

Question

我有一个方法 addToClonedList(List)在类里面App调用方法 add(List)在类里面Dependency .我要单元测试 addToClonedList(List) ，我想创建一个模拟 Dependency对象(称为 mockDependency )并验证方法 mockDependency.add(List)使用正确的参数调用。然而，由于 List clonedList 引用的实例在有问题的调用之后获取一个新元素( 100 )添加到 if 中，Mockito 认为 2 元素 List被传递给了mockDependency , 测试失败。实际上，List传递给 mockDependency.add(List)调用时只包含一个元素。这是预期的 Mockito 行为吗？有没有更标准的方法来测试我是否通过了正确的 List至 mockDependency.add(List) ？

在下面查看我的代码结构和测试输出:

ma​​in/java/App.java:

import java.util.*;

public class App {
  Dependency dataLayer = new Dependency();

  void addToClonedList(List<Integer> integerList) {
    List<Integer> clonedList = new ArrayList<Integer>(integerList);
    dataLayer.add(clonedList);
    clonedList.add(100);
  }
}

ma​​in/java/Dependency.java:

import java.util.List;

public class Dependency {
  void add(List<Integer> integerList) {
    //
  }
}

测试/java/AppTest.java:

import java.util.*;
import org.junit.*;
import org.mockito.*;

public class AppTest {

  @InjectMocks
  App app;

  @Mock
  Dependency mockDependency;

  @Before
  public void beforeEachTest() {
    MockitoAnnotations.initMocks(this);
  }

  @Test
  public void testWithVerify() {
    List<Integer> originalList = new ArrayList<>();
    originalList.add(1);

    app.addToClonedList(originalList);

    Mockito.verify(mockDependency).add(Mockito.eq(originalList));
  }
}

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.athenahealth</groupId>
  <artifactId>mockitotest</artifactId>
  <version>1.0-SNAPSHOT</version>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
          <source>1.7</source>
          <target>1.7</target>
        </configuration>
      </plugin>
    </plugins>
  </build>

  <dependencies>
    <dependency>
      <groupId>org.testifyproject.mock</groupId>
      <artifactId>mockito</artifactId>
      <version>0.9.8</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.12</version>
    </dependency>
  </dependencies>

</project>

测试输出:

Argument(s) are different! Wanted:
mockDependency.add([1]);
-> at AppTest.testWithVerify(AppTest.java:25)
Actual invocation has different arguments:
mockDependency.add([1, 100]);
-> at App.addToClonedList(App.java:8)

Comparison Failure: 
Expected :mockDependency.add([1]);
Actual   :mockDependency.add([1, 100]);

Answer 1

As Andy Turner notes ，问题是 Mockito 只保留对传递值的引用，而不克隆它。这是有道理的，因为它对于像 String 这样的不可变值对象来说是一种浪费，而且对于像 Thread 这样的某些引用实际上是不可能的。

但是，您可以编写自己的答案来自己制作该副本:

List<Integer> listSnapshot;

@Test
public void testWithVerify() {
  List<Integer> originalList = new ArrayList<>();
  originalList.add(1);
  Mockito.when(mockDependency.add(any())).thenAnswer(invocation => {
    listSnapshot = new ArrayList<>((List<Integer>) (invocation.getArguments()[0]));
  });

  app.addToClonedList(originalList);

  assertEquals(originalList, listSnapshot);
}