How to mock a for loop using mockito

Today when I tried to use mockito to write unit test cases, I found I need to mock the for loop operation. Then I found the solution from here in stackoverflow: the basic idea is to mock the iterator class and collection class, and base on your situation, you need to set the expectation of iterator.hasNext() and iterator.next() method.

The following code is copied from the above link:

	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, 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);
	}
	}

view raw gistfile1.java hosted with ❤ by GitHub