Mockito Example

UtilizationController.java

package com.example.tdd;

import java.math.BigDecimal;

public class UtilizationController {
	
	private CalculatesAverage calculatesAverage;
	private CountsHoursInMonth countsHoursInMonth;
	private AccumulatesActualsInMonth accumulatesActualsInMonth;
	
	public BigDecimal calculate(Integer month, Integer year) {
		return calculatesAverage.calculate(
				countsHoursInMonth.count(month, year), 
				accumulatesActualsInMonth.accumulate(month, year));
	}

}

UtilizationControllerTest.java

package com.example.tdd;

import static org.junit.Assert.*;

import java.math.BigDecimal;

import static org.mockito.Mockito.*;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.InjectMocks;
import org.mockito.Mock;
import org.mockito.runners.MockitoJUnitRunner;

@RunWith(MockitoJUnitRunner.class)
public class UtilizationControllerTest {

	@InjectMocks private  UtilizationController subject; 
	
	@Mock private CalculatesAverage calculatesAverage;
	@Mock private CountsHoursInMonth countsHoursInMonth;
	@Mock private AccumulatesActualsInMonth accumulatesActualsInMonth;
	
	@Mock private DogRepository dogRepository;
	
	@Test
	public void calculatesAverageBasedOnActualsAndAvailable() {
		Integer month = 2;
		Integer year = 1999;
		Integer totalAvailableHours = 98765;
		Integer totalActualHours = 12345;		
		when(countsHoursInMonth.count(month, year)).thenReturn(totalAvailableHours);
		when(accumulatesActualsInMonth.accumulate(month, year)).thenReturn(totalActualHours);
		when(calculatesAverage.calculate(totalAvailableHours, totalActualHours)).thenReturn(new BigDecimal("12.34"));
		
		BigDecimal result = subject.calculate(month , year);
		
		assertEquals(new BigDecimal("12.34"), result);
	}
	
	@Test
	public void savesDog() {
		Object dog = new Object();
		
		dogRepository.save(dog);
		
		verify(dogRepository).save(dog);
	}

}