莫米托 - "Wanted but not invoked; However there were other interactions with this mock"错误

Question

我正在验证使用Mockito调用的函数，但是Mockito告诉我我正在验证的函数从未被调用过，并且调用了其他函数。但在我看来，我正在调用正确的函数…

下面是我得到的错误的堆栈跟踪:

Wanted but not invoked:
relationshipAutoIndexer.getAutoIndex();
-> at org.whispercomm.manes.server.graph.DataServiceImplTest.testInitIndices(DataServiceImplTest.java:117)
However, there were other interactions with this mock:
-> at org.whispercomm.manes.server.graph.DataServiceImpl.updateIndexProperties(DataServiceImpl.java:136)
-> at org.whispercomm.manes.server.graph.DataServiceImpl.updateIndexProperties(DataServiceImpl.java:144)
-> at org.whispercomm.manes.server.graph.DataServiceImpl.updateIndexProperties(DataServiceImpl.java:148)
-> at org.whispercomm.manes.server.graph.DataServiceImpl.updateIndexProperties(DataServiceImpl.java:149)
-> at org.whispercomm.manes.server.graph.DataServiceImpl.initIndices(DataServiceImpl.java:121)
    at org.whispercomm.manes.server.graph.DataServiceImplTest.testInitIndices(DataServiceImplTest.java:117)

出现在

verify(relAutoIndexer).getAutoIndex();

的测试类代码如下所示。

这是我的代码(我有一种偶然遗漏的倾向)。请问我的任何代码，你认为我错过了，我会添加它):

public DataServiceImpl(GraphDatabaseService graphDb) {
    super();
    this.graphDb = graphDb;
    unarchivedParent = new UnarchivedParent(graphDb.createNode());
    archivedParent = new ArchivedParent(graphDb.createNode());
    packetParent = new PacketParent(graphDb.createNode());
    userParent = new UserParent(graphDb.createNode());
    this.initIndices();
}
/**
 * Initializes the node and relationship indexes.
 * 
 * Updates the set of indexed properties to match {@link DataServiceImpl}
 * .NODE_KEYS_INDEXABLE and {@link DataServiceImpl}.REL_KEYS_INDEXABLE.
 * 
 * Note: auto indices can also be configured at database creation time and
 * just retrieved at runtime. We might want to switch to that later.
 */
private void initIndices() {
    /* Get the auto-indexers */
    AutoIndexer<Node> nodeAutoIndexer = this.graphDb.index()
            .getNodeAutoIndexer();
    AutoIndexer<Relationship> relAutoIndexer = this.graphDb.index()
            .getRelationshipAutoIndexer();
    this.updateIndexProperties(nodeAutoIndexer,
            DataServiceImpl.NODE_KEYS_INDEXABLE);
    this.nodeIndex = nodeAutoIndexer.getAutoIndex();
    this.updateIndexProperties(relAutoIndexer,
            DataServiceImpl.REL_KEYS_INDEXABLE);
    this.relIndex = relAutoIndexer.getAutoIndex();
}
/**
 * Sets the indexed properties of an {@link AutoIndexer} to the specified
 * set, removing old properties and adding new ones.
 * 
 * @param autoIndexer
 *            the AutoIndexer to update.
 * @param properties
 *            the properties to be indexed.
 * @return autoIndexer, this given AutoIndexer (useful for chaining calls.)
 */
private <T extends PropertyContainer> AutoIndexer<T> updateIndexProperties(
        AutoIndexer<T> autoIndexer, Set<String> properties) {
    Set<String> indexedProps = autoIndexer.getAutoIndexedProperties();
    // Remove unneeded properties.
    for (String prop : difference(indexedProps, properties)) {
        autoIndexer.stopAutoIndexingProperty(prop);
    }
    // Add new properties.
    for (String prop : difference(properties, indexedProps)) {
        autoIndexer.startAutoIndexingProperty(prop);
    }
    // Enable the index, if needed.
    if (!autoIndexer.isEnabled()) {
        autoIndexer.setEnabled(true);
    }
    return autoIndexer;
}

下面是测试类的代码:

@Before
public void setup() {
   nA = mock(Node.class);
   nB = mock(Node.class);
   packetA = new PacketWrapper(nA);
   packetB = new PacketWrapper(nB);
   RelA = mock(Relationship.class);
   RelB = mock(Relationship.class);
   graphDb = mock(GraphDatabaseService.class);
   nodeAutoIndexer = (AutoIndexer<Node>) mock(AutoIndexer.class);
       relAutoIndexer = mock(RelationshipAutoIndexer.class);
}
@After
public void tearDown() {
  packetA = null;
  packetB = null;
}
/*
 * ---------------- Test initIndices() ---------------
 */
//TODO
@Test
public void testInitIndices() throws IllegalArgumentException, IllegalAccessException, InvocationTargetException, NoSuchMethodException {
   IndexManager indexManager = mock(IndexManager.class);
   when(graphDb.index()).thenReturn(indexManager);
   when(indexManager.getNodeAutoIndexer()).thenReturn(nodeAutoIndexer);
       when(graphDb.index().getRelationshipAutoIndexer()).thenReturn(relAutoIndexer);
   dataService = new DataServiceImpl(graphDb);
       verify(nodeAutoIndexer, atLeastOnce()).getAutoIndex();
       verify(relAutoIndexer).getAutoIndex();                       
}

Answer 1

Mockito，直到1.8.5版本，在多态调度的情况下有一个错误。它已经修复，并且在1.9.0版本的第一个候选发行版中可用。参见第200期。

那么它是如何在你的代码库中发生的呢?注意，您正在模拟这两个类

nodeAutoIndexer = (AutoIndexer<Node>) mock(AutoIndexer.class);
relAutoIndexer = mock(RelationshipAutoIndexer.class);

AutoIndexer恰好是一个泛型父接口，在这个接口中有这个方法ReadableIndex<T> getAutoIndex()。RelationshipAutoIndexer是AutoInexer的子类型，其泛型部分固定为Relationship，覆盖getAutoIndex()方法返回协变类型ReadableRelationshipIndex。

参见AutoIndexer和RelationshipIndexer。

嗯，在你的调用代码中，你有这些行:

AutoIndexer<Node> nodeAutoIndexer = this.graphDb.index().getNodeAutoIndexer();
AutoIndexer<Relationship> relAutoIndexer = this.graphDb.index().getRelationshipAutoIndexer();
this.nodeIndex = nodeAutoIndexer.getAutoIndex();
this.relIndex = relAutoIndexer.getAutoIndex();

生产代码中的nodeAutoIndex和测试代码中的mock nodeAutoIndexer都有一个类型为AutoIndexer<Node>的引用，因此在多态调度方面没有问题。但是，生产代码中的relAutoIndex由类型AutoIndexer<Relationship>引用，测试代码中的模拟relAutoIndexer由类型RelationshipAutoIndexer引用，因此在模拟上注册了错误的调用，然后验证失败。

你的解决方案是要么升级mockito版本;1.9.0 RC1非常稳定，最终版本即将发布。或者您可以将引用类型(在您的生产代码中)从:

迁移到

AutoIndexer<Relationship> relAutoIndexer = this.graphDb.index().getRelationshipAutoIndexer();

to:

RelationshipAutoIndexer relAutoIndexer = this.graphDb.index().getRelationshipAutoIndexer();

---

还有几句话。

• 您实际上不需要在这里编写after方法，因为JUnit在每个方法运行时都会创建一个新实例，因此您的方法只是添加了无论如何都会完成的代码。注意，TestNG不是这样的。

• 您可能希望使用Mockito注释，而不是在before方法中创建mock。别忘了跑步者。

例如:

@RunWith(MockitoJUnitRunner.class)
public class YourTest {
    @Mock SomeType someTypeMock;
    // ...
}

• 由于几个原因，存根代码有点难看。

  • 你应该写一致的存根

为什么不以一种更简洁的方式来写呢?例如，在两种情况下都引用indexManager:

IndexManager indexManager = mock(IndexManager.class);
when(graphDb.index()).thenReturn(indexManager);
when(indexManager.getNodeAutoIndexer()).thenReturn(nodeAutoIndexer);
when(indexManager.getRelationshipAutoIndexer()).thenReturn(relAutoIndexer);

或者根本不引用

IndexManager indexManager = mock(IndexManager.class);
when(graphDb.index()).thenReturn(indexManager);
when(graphDb.index().getNodeAutoIndexer()).thenReturn(nodeAutoIndexer);
when(graphDb.index().getRelationshipAutoIndexer()).thenReturn(relAutoIndexer);

拥有一个返回一个mock的mock通常是设计异味的标志。您违反了Demeter法则，而违反它意味着您将经历困难的测试、糟糕的可维护性和困难的进化。当我这样说的时候，你也能听到我的低语(没有三段论):这将花费你的钱。不要写遗留代码!如果您正在实践TDD或BDD，您将在设计时为自己的代码识别这些问题，这对于防止它们非常有用。

然而，如果你正在处理遗留代码，你可以使用这种深存根语法:

使用静态方法你可以这样写

GraphDatabaseService graphdb = mock(GraphDatabaseService.class, RETURNS_DEEP_STUBS);

或者使用注释你可以这样写:

@Mock(answer = RETURNS_DEEP_STUBS) GraphDatabaseService graphdb;

和存根:

when(graphDb.index().getNodeAutoIndexer()).thenReturn(nodeAutoIndexer);
when(graphDb.index().getRelationshipAutoIndexer()).thenReturn(relAutoIndexer);