Mocking a void method with EasyMock

Issue: BAEL-2952

testing-modules/easymock/pom.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0"?>
+<project
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
+    xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>testing-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+    <artifactId>easymock</artifactId>
+    <name>easymock</name>
+    <url>http://maven.apache.org</url>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>org.easymock</groupId>
+            <artifactId>easymock</artifactId>
+            <version>4.0.2</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

testing-modules/easymock/src/main/java/com/baeldung/testing/easymock/ForecastProcessor.java

@@ -0,0 +1,28 @@
+package com.baeldung.testing.easymock;
+
+import java.math.BigDecimal;
+
+public class ForecastProcessor {
+    private WeatherService weatherService;
+    
+    public BigDecimal getMaximumTemperature(String locationName) {
+        
+        Location location = new Location(locationName);
+        
+        try {
+            weatherService.populateTemperature(location);
+        } catch (ServiceUnavailableException e) {
+           return null;
+        }
+        
+        return location.getMaximumTemparature();
+    }
+
+    public WeatherService getWeatherService() {
+        return weatherService;
+    }
+
+    public void setWeatherService(WeatherService weatherService) {
+        this.weatherService = weatherService;
+    }    
+}

testing-modules/easymock/src/main/java/com/baeldung/testing/easymock/Location.java

@@ -0,0 +1,33 @@
+package com.baeldung.testing.easymock;
+
+import java.math.BigDecimal;
+
+public class Location {
+    private String name;
+    private BigDecimal minimumTemperature;
+    private BigDecimal maximumTemparature;
+    
+    public Location(String name) {
+        this.name = name;
+    }   
+    
+    public String getName() {
+        return name;
+    }
+    
+    public BigDecimal getMinimumTemperature() {
+        return minimumTemperature;
+    }
+    
+    public void setMinimumTemperature(BigDecimal minimumTemperature) {
+        this.minimumTemperature = minimumTemperature;
+    }
+    
+    public BigDecimal getMaximumTemparature() {
+        return maximumTemparature;
+    }
+    
+    public void setMaximumTemparature(BigDecimal maximumTemparature) {
+        this.maximumTemparature = maximumTemparature;
+    }
+}

testing-modules/easymock/src/main/java/com/baeldung/testing/easymock/ServiceUnavailableException.java

@@ -0,0 +1,7 @@
+package com.baeldung.testing.easymock;
+
+public class ServiceUnavailableException extends Exception {
+
+    private static final long serialVersionUID = 6961151537340723535L;
+
+}

testing-modules/easymock/src/main/java/com/baeldung/testing/easymock/WeatherService.java

@@ -0,0 +1,5 @@
+package com.baeldung.testing.easymock;
+
+public interface WeatherService {
+    void populateTemperature(Location location) throws ServiceUnavailableException;
+}

testing-modules/easymock/src/test/java/com/baeldung/testing/easymock/ForecastProcessorUnitTest.java

@@ -0,0 +1,49 @@
+package com.baeldung.testing.easymock;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertThat;
+
+import java.math.BigDecimal;
+
+import org.easymock.EasyMock;
+import org.easymock.EasyMockRule;
+import org.easymock.Mock;
+import org.easymock.TestSubject;
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+
+public class ForecastProcessorUnitTest {
+    private static int MAX_TEMP = 90;
+    
+    @Rule
+    public EasyMockRule rule = new EasyMockRule(this);
+
+    @TestSubject
+    private ForecastProcessor forecastProcessor = new ForecastProcessor();
+
+    @Mock
+    private WeatherService mockWeatherService;
+
+    @Before
+    public void setUp() {
+        forecastProcessor.setWeatherService(mockWeatherService);
+    }
+
+    @SuppressWarnings("unchecked")
+    @Test
+    public void givenLocationName_whenWeatherServicePopulatesTemperatures_thenMaxTempReturned() throws ServiceUnavailableException {
+        mockWeatherService.populateTemperature(EasyMock.anyObject(Location.class));
+        EasyMock.expectLastCall()
+            .andAnswer(() -> {
+                Location passedLocation = (Location) EasyMock.getCurrentArguments()[0]; 
+                passedLocation.setMaximumTemparature(new BigDecimal(MAX_TEMP)); 
+                passedLocation.setMinimumTemperature(new BigDecimal(MAX_TEMP - 10));
+                return null;
+            });
+        EasyMock.replay(mockWeatherService);
+        BigDecimal maxTemperature = forecastProcessor.getMaximumTemperature("New York");
+        EasyMock.verify(mockWeatherService);
+        assertThat(maxTemperature, equalTo(new BigDecimal(MAX_TEMP)));
+    }
+}

testing-modules/pom.xml

@@ -33,6 +33,7 @@
         <module>testing</module>
         <module>testng</module>
         <module>junit-5-basics</module>
+        <module>easymock</module>
         <module>junit-5-advanced</module>
     </modules>
 </project>