java - 使用 ArrayList 私有(private)成员测试类

Question

我有一个具有以下实现的 Java 类:

    class Some {
      private ArrayList<SomeObject> list = new...

      public void addToList(Long t) {
          SomeObject so = new SomeObject(new Date, t)
          list.add(so)
      } 

      private float fun1(ArrayList<SomeObject> x) {
      //some operations on list "list", 
      //res - result of float calculations based on list "x"
      return res
      }

      public float publicFun() {
         //some other operations on private list "list"
         return fun1(list);
      }

问题是如何使用 Mockito、PowerMock 或其他测试工具测试函数 publicFun()？要运行此公共(public)功能，我必须模拟私有(private)列表，但我该怎么做？

Answer 1

在这个例子中，有几个问题是由不受欢迎的依赖引起的:

1 新日期()为了解决这个问题，我建议引入新界面

interface CurrentTimeProvider {
    Date getCurrentDate();
}

实现是显而易见的(为简洁起见，我跳过它)

2 是新的ArrayList()

• 你可以用你自己的接口(interface)替换它(只包含方法你需要)
• 你可以模拟 ArrayList 本身
• 您可以使用 ArrayList 的实际实现并完全测试它

结果我们得到这样的结果:

class Some {
  private CurrentTimeProvider timeProvider;
  private ArrayList<SomeObject> list = new ArrayList<SomeObject>();

  public void setTimeProvider(CurrentTimeProvider timeProvider) {
      this.timeProvider = timeProvider;
  }

  public void addToList(Long t) {
      SomeObject so = new SomeObject(timeProvider.getCurrentDate(), t)
      list.add(so)
  } 

  public float publicFun() {
     //some other operations on private list "list"
     return fun1(list);
  }

测试看起来是这样的:

CurrentTimeProvider timeProvider = mock(CurrentTimeProvider.class);
Some some = new Some();
some.setTimeProvider(timeProvider);

when(timeProvider.getCurrentDate).thenReturn(mock(Date.class));

//Invoke you method
some.publicFun();

//Put assert and verify here