当我结合构造函数注入(子类)和属性注入(父类)时，@InjectMocks 给我 null

问题描述

我有一个带有注入属性的摘要.这是由一个子类扩展的，其中注入是通过构造函数完成的.在单元测试中，@InjectMocks 为抽象类中注入的属性提供 null.

I have an abstract with an injected property. This is extended by a child class where the injection is done via constructor. In the Unit test, the @InjectMocks gives null for the property injected in the abstract class.

查看下面的代码.

我想了解为什么在这种特定情况下 @InjectMocks 不知道从抽象类中注入属性.有人可以帮我理解吗?非常感谢！！！

I would like to understand why in this specific situation the @InjectMocks does not know to inject the property from the abstract class.Can anybody help me to understand?Thanks a lot!!!

如果子类和父类都使用属性注入，我的单元测试就没有问题.

If both child and parent class uses property injection, my unit test works without problems.

public abstract class AbstractClass
{
  @Inject
  private D d;
  ...
}

@RequestScoped
public class ConcreteClass extends AbstractClass
{
  private A a;
  private B b;
  private C c;

  @Inject
  public ConcreteClass(A a, B b, C c)
  {
    this.a = a;
    this.b = b;
    this.c = c;
  }

  /**
   * CDI, no arguments constructor.
   */
  public ConcreteClass()
  {
    // CDI constructor
  }
}

@RunWith(Theories.class)
public class ConcreteClassTest
{
  @Mock
  D d;

  @Mock
  A a;

  @InjectMocks
  ConcreteClass concreteClass;

 @Before
  public void setUp() throws Exception
  {
   ...
    MockProvider.setMockForClass(A.class, a);
    MockProvider.setMockForClass(D.class, d);
    ...
  }

  @Theory
  public void testMethod()
  {
    ...
    concreteClass.methodXXX();
    //here if i inspect the concreteClass i see that the attribute "a" has    value and attribute "d" is null.
    ...
  }

}

推荐答案

来自 mockito 文档:
https://static.javadoc.io/org.mockito/mockito-core/3.0.0/org/mockito/InjectMocks.html

From the mockito documentation:
https://static.javadoc.io/org.mockito/mockito-core/3.0.0/org/mockito/InjectMocks.html

构造函数注入；选择最大的构造函数，然后使用仅在测试中声明的模拟来解析参数.如果使用构造函数成功创建了对象，则 Mockito 不会尝试其他策略.Mockito 决定不破坏具有参数构造函数的对象.

因为你的构造函数只有 A、B、C，mockito 没有处理 D.
(不考虑属性或字段注入)

As your constructor only has A, B, C mockito does not take care of D.
(Property or Field injection are not considered)

您可以更改构造函数，使其具有全部 4 个值并将 D 传递给超类.

You could change your Constructor so that it has all 4 values and passes on D to the superclass.

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