Unit testing with Mockito

In this article I created a realistic scenario of services depending on each other. This article shows you how you can easily test business logic in isolation.

	/************************************************/
	DOMAIN OBJECTS
	*************************************************/
	/*********** Coordinates.java *******************/
	package com.pelssers.domain;
	public class Coordinates {
	private Double latitude;
	private Double longitude;
	public Coordinates(Double latitude, Double longitude) {
	this.latitude = latitude;
	this.longitude = longitude;
	}
	public Double getLatitude() {
	return latitude;
	}
	public Double getLongitude() {
	return longitude;
	}
	}
	/*********** Weather.java *******************/
	package com.pelssers.domain;
	import java.util.Set;
	public class Weather {
	private Double temperature;
	private Set<WeatherType> weatherTypes;
	public Weather(Double temperature, Set<WeatherType> weatherTypes) {
	this.temperature = temperature;
	this.weatherTypes = weatherTypes;
	}
	public Double getTemperature() {
	return temperature;
	}
	public Set<WeatherType> getWeatherTypes() {
	return weatherTypes;
	}
	@Override
	public String toString() {
	return "{temperature: " + getTemperature().toString() +
	", weatherTypes: [" + weatherTypes.toString() + "]";
	}
	}
	/*********** WeatherType.java *******************/
	package com.pelssers.domain;
	public enum WeatherType {
	RAINY, DRY, SUNNY, CLOUDY
	}
	/************************************************/
	SERVICE INTERFACES
	*************************************************/
	/*********** IHumidityService.java *************/
	package com.pelssers.services;
	import java.util.Date;
	import com.pelssers.domain.Coordinates;
	public interface IHumidityService {
	Double predictHumidity(Date date, Coordinates coordinates);
	}
	/*********** ISatteliteService.java *************/
	package com.pelssers.services;
	import java.util.Date;
	import com.pelssers.domain.Coordinates;
	public interface ISatteliteService {
	boolean isCloudy(Date date, Coordinates coordinates);
	}
	/*********** ITemperatureService.java *************/
	package com.pelssers.services;
	import java.util.Date;
	import com.pelssers.domain.Coordinates;
	public interface ITemperatureService {
	Double predictTemperature(Date date, Coordinates coordinates);
	}
	/*********** IWeatherForecastService.java *************/
	package com.pelssers.services;
	import java.util.Date;
	import com.pelssers.domain.Coordinates;
	import com.pelssers.domain.Weather;
	public interface IWeatherForecastService {
	Weather getForecast(Date date, Coordinates coordinates);
	}
	/************************************************/
	SERVICE IMPLEMENTATION(S)
	*************************************************/
	/*********** WeatherForecastService.java *************/
	package com.pelssers.services.impl;
	import java.util.Date;
	import java.util.HashSet;
	import java.util.Set;
	import javax.inject.Inject;
	import org.springframework.stereotype.Component;
	import com.pelssers.domain.Coordinates;
	import com.pelssers.domain.Weather;
	import com.pelssers.domain.WeatherType;
	import com.pelssers.services.ISatteliteService;
	import com.pelssers.services.ITemperatureService;
	import com.pelssers.services.IWeatherForecastService;
	import com.pelssers.services.IHumidityService;
	@Component()
	public class WeatherForecastService implements IWeatherForecastService {
	@Inject
	private ITemperatureService temperatureService;
	@Inject
	private IHumidityService humidityService;
	@Inject
	private ISatteliteService satteliteService;
	@Override
	public Weather getForecast(Date date, Coordinates coordinates) {
	final Double predictedTemperature = temperatureService.predictTemperature(date, coordinates);
	final Double predictedHumidity = humidityService.predictHumidity(date, coordinates);
	final boolean isCloudy = satteliteService.isCloudy(date, coordinates);
	//here starts our actual business logic
	Set<WeatherType> weatherTypes = new HashSet<WeatherType>();
	weatherTypes.add(isCloudy? WeatherType.CLOUDY : WeatherType.SUNNY);
	weatherTypes.add(predictedHumidity > 50 ? WeatherType.RAINY : WeatherType.DRY);
	return new Weather(predictedTemperature, weatherTypes);
	}
	}
	/************************************************/
	UNIT TEST
	*************************************************/
	package com.pelssers.services.impl;
	import java.util.Date;
	import org.junit.Assert;
	import org.junit.Before;
	import org.junit.Test;
	import org.mockito.InjectMocks;
	import org.mockito.Mock;
	import org.mockito.MockitoAnnotations;
	import static org.mockito.Matchers.*;
	import static org.mockito.Mockito.*;
	import com.google.common.collect.ImmutableSet;
	import com.pelssers.domain.Coordinates;
	import com.pelssers.domain.Weather;
	import com.pelssers.domain.WeatherType;
	import com.pelssers.services.IHumidityService;
	import com.pelssers.services.ISatteliteService;
	import com.pelssers.services.ITemperatureService;
	import com.pelssers.services.IWeatherForecastService;
	public class WeatherForecastServiceTest {
	/**
	* As our weather forecast service depends on lots of other services
	* we want to mock the services we depend on and test our business logic
	* in isolation. As you can see we no longer need setters and getters in
	* WeatherForecastService, not for dependency injection and neither for unit testing
	*/
	@InjectMocks
	private IWeatherForecastService weatherForecastService = new WeatherForecastService();
	@Mock
	private IHumidityService humidityService;
	@Mock
	private ITemperatureService temperatureService;
	@Mock
	private ISatteliteService satteliteService;
	private Coordinates coordinates;
	private Date forecastDate;
	private Double expectedTemperature;
	@Before
	public void setUp() {
	//instruct mockito to process all annotations
	MockitoAnnotations.initMocks(this);
	forecastDate = new Date(2013, 10 , 1);
	coordinates = new Coordinates(14.5, 123.4);
	expectedTemperature = 16D;
	when(temperatureService.predictTemperature(any(Date.class), any(Coordinates.class)))
	.thenReturn(expectedTemperature);
	}
	@Test
	public void testRainyAndCloudyWeather() {
	Weather expectedWeather = new Weather(expectedTemperature,
	ImmutableSet.of(WeatherType.RAINY, WeatherType.CLOUDY));
	when(humidityService.predictHumidity(any(Date.class), any(Coordinates.class)))
	.thenReturn(60D);
	when(satteliteService.isCloudy(any(Date.class), any(Coordinates.class)))
	.thenReturn(true);
	testWeather(expectedWeather);
	}
	@Test
	public void testDryAndSunnyWeather() {
	Weather expectedWeather = new Weather(expectedTemperature,
	ImmutableSet.of(WeatherType.DRY, WeatherType.SUNNY));
	when(humidityService.predictHumidity(any(Date.class), any(Coordinates.class)))
	.thenReturn(40D);
	when(satteliteService.isCloudy(any(Date.class), any(Coordinates.class)))
	.thenReturn(false);
	testWeather(expectedWeather);
	}
	private void testWeather(Weather expectedWeather) {
	Weather actualWeather = weatherForecastService.getForecast(forecastDate, coordinates);
	//verify our services are called once
	verify(humidityService, times(1)).predictHumidity(forecastDate, coordinates);
	verify(temperatureService, times(1)).predictTemperature(forecastDate, coordinates);
	verify(satteliteService, times(1)).isCloudy(forecastDate, coordinates);
	Assert.assertEquals(expectedWeather.getTemperature(), actualWeather.getTemperature());
	Assert.assertEquals(expectedWeather.getWeatherTypes(), actualWeather.getWeatherTypes());
	}
	}

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	<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.pelssers</groupId>
	<artifactId>mockitodemo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>Mockito Demo</name>
	<packaging>jar</packaging>
	<properties>
	<spring.version>3.1.2.RELEASE</spring.version>
	</properties>
	<dependencies>
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-core</artifactId>
	<version>${spring.version}</version>
	<scope>compile</scope>
	</dependency>
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-beans</artifactId>
	<version>${spring.version}</version>
	<scope>compile</scope>
	</dependency>
	<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-context</artifactId>
	<version>${spring.version}</version>
	<scope>compile</scope>
	</dependency>
	<dependency>
	<groupId>javax.inject</groupId>
	<artifactId>javax.inject</artifactId>
	<version>1</version>
	</dependency>
	<dependency>
	<groupId>com.google.guava</groupId>
	<artifactId>guava</artifactId>
	<version>14.0.1</version>
	</dependency>
	<!-- Test Dependencies -->
	<dependency>
	<groupId>junit</groupId>
	<artifactId>junit</artifactId>
	<version>4.8.2</version>
	<scope>test</scope>
	</dependency>
	<dependency>
	<groupId>org.mockito</groupId>
	<artifactId>mockito-core</artifactId>
	<version>1.9.5</version>
	<scope>test</scope>
	</dependency>
	</dependencies>
	</project>

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