[英]Using Guice, how do I inject a mock object from my unit test, into the class being tested
Consider the following code:考虑以下代码:
@Singleton
public class MyServiceImpl {
public int doSomething() {
return 5;
}
}
@ImplementedBy(MyServiceImpl.class)
public interface MyService {
public int doSomething();
}
public class MyCommand {
@Inject private MyService service;
public boolean executeSomething() {
return service.doSomething() > 0;
}
}
public class MyCommandTest {
@InjectMocks MyServiceImpl serviceMock;
private MyCommand command;
@Before public void beforeEach() {
MockitoAnnotations.initMocks(this);
command = new MyCommand();
when(serviceMock.doSomething()).thenReturn(-1); // <- Error here
}
@Test public void mockInjected() {
boolean result = command.executeSomething();
verify(serviceMock).doSomething();
assertThat(result, equalTo(false));
}
}
My test is falling over when I attempt to stub the doSomething() method on my mock implementation object.当我尝试在模拟实现对象上存根 doSomething() 方法时,我的测试失败了。 I get the error:
我收到错误:
org.mockito.exceptions.misusing.MissingMethodInvocationException: when() requires an argument which has to be 'a method call on a mock'.
org.mockito.exceptions.misusing.MissingMethodInvocationException: when() 需要一个必须是“模拟方法调用”的参数。 For example: when(mock.getArticles()).thenReturn(articles);
例如:when(mock.getArticles()).thenReturn(articles);
Also, this error might show up because: 1. you stub either of: final/private/equals()/hashCode() methods.
此外,出现此错误的原因可能是: 1. 您存根了以下任一方法: final/private/equals()/hashCode() 方法。 Those methods cannot be stubbed/verified.
这些方法不能被存根/验证。 Mocking methods declared on non-public parent classes is not supported.
不支持在非公共父类上声明的模拟方法。 2. inside when() you don't call method on mock but on some other object.
2. 在 when() 中,您不会在模拟上调用方法,而是在其他对象上调用方法。
I am new to dependency injection via Guice, and am not sure why I cannot mock the implementation object in this way?我是通过 Guice 进行依赖注入的新手,不知道为什么我不能以这种方式模拟实现对象?
A simple solution is to combine CDI with Constructor Injection, and forget about Guice for the test:一个简单的解决方案是将 CDI 与构造函数注入结合起来,而无需考虑 Guice 进行测试:
public class MyCommand {
private final MyService service;
@Inject
public MyCommand(MyService service) {
this.service = service;
}
public boolean executeSomething() {
return service.doSomething() > 0;
}
}
@RunWith(MockitoJUnitRunner.class)
public class MyCommandTest {
@Mock
MyServiceImpl serviceMock;
private MyCommand command;
@Before public void beforeEach() {
MockitoAnnotations.initMocks(this);
when(serviceMock.doSomething()).thenReturn(-1); // <- Error here
// inject without Guice
command = new MyCommand(serviceMock);
}
}
Else, if you do not like Constructor Injection, the test code should look like this:否则,如果您不喜欢构造函数注入,则测试代码应如下所示:
@RunWith(MockitoJUnitRunner.class)
public class MyCommandTest {
@Mock
MyServiceImpl serviceMock;
@InjectMocks
private MyCommand command;
@Before
public void beforeEach() {
MockitoAnnotations.initMocks(this);
command = new MyCommand();
when(serviceMock.doSomething()).thenReturn(-1); // <- Error here
}
}
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