使用Mockito来测试Java的行为

我想测试一个使用Mockito对其进行增强的
java方法.问题是当我不知道如何设定增强工作的期望.以下代码从
an unanswered question in the mockito google group获得：

import static org.mockito.Mockito.when;
import static org.testng.Assert.assertTrue;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.mockito.Mockito;
import org.testng.annotations.Test;

public class ListTest
{

  @Test
  public void test()
  {
    List<String> mockList = Mockito.mock(List.class);
    Iterator<String> mockIterator = Mockito.mock(Iterator.class);

    when(mockList.iterator()).thenReturn(mockIter);
    when(mockIter.hasNext()).thenReturn(true).thenReturn(false);
    when(mockIter.next()).thenReturn("A");

    boolean flag = false;
    for(String s : mockList) {
        flag = true;
    }
    assertTrue(flag);
  }
}

for循环中的代码不会被执行.设置迭代器的期望不起作用,因为java enhanced for不在内部使用list iterator.设置List.get()方法的期望不是因为增强的实现似乎也不调用列表的get()方法.

任何帮助将不胜感激.

解决方法

模拟迭代器为我工作.见下面的代码示例：

import static org.junit.Assert.assertEquals;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import java.util.Collection;
import java.util.Iterator;

import org.junit.Before;
import org.junit.Test;

public class TestMockedIterator {

    private Collection<String> fruits;
    private Iterator<String> fruitIterator;

    @SuppressWarnings("unchecked")
    @Before
    public void setUp() {
        fruitIterator = mock(Iterator.class);
        when(fruitIterator.hasNext()).thenReturn(true,true,false);
            when(fruitIterator.next()).thenReturn("Apple")
            .thenReturn("Banana").thenReturn("Pear");

        fruits = mock(Collection.class);
        when(fruits.iterator()).thenReturn(fruitIterator);
    }

    @Test
    public void test() {
        int iterations = 0;
        for (String fruit : fruits) {
            iterations++;
        }
        assertEquals(3,iterations);
    }
}