Stubbing is defining of what values to return when we invoke methods of a mock object.
Stubbing is achieved by Mockito's when-thenReturn or doReturn-when methods.
Example
Example Application
mockito-defining-return-values-by-method-stubbing/src/main/java/com/logicbig/example/MyService.javapackage com.logicbig.example;
public interface MyService {
public int doSomething();
}
mockito-defining-return-values-by-method-stubbing/src/main/java/com/logicbig/example/MyProcessor.javapackage com.logicbig.example;
public class MyProcessor {
private MyService myService;
public MyProcessor(MyService myService) {
this.myService = myService;
}
public String process() {
int returnInteger = myService.doSomething();
return String.format("My Integer is: " + returnInteger);
}
}
Stubbing methods
Using when-theReturn
mockito-defining-return-values-by-method-stubbing/src/test/java/com/logicbig/example/ProcessorTest.javapackage com.logicbig.example;
import org.junit.Assert;
import org.junit.Test;
import org.mockito.Mockito;
public class ProcessorTest {
@Test
public void processTest() {
MyService myService = Mockito.mock(MyService.class);
Mockito.when(myService.doSomething()).thenReturn(10);
MyProcessor myProcessor = new MyProcessor(myService);
String returnedValue = myProcessor.process();
Assert.assertEquals(returnedValue, "My Integer is: 10");
}
}
D:\mockito-consecutive-method-calls-stubbing>mvn test -Dtest="ProcessorTest" [INFO] Scanning for projects... [INFO] [INFO] ---< com.logicbig.example:mockito-consecutive-method-calls-stubbing >--- [INFO] Building mockito-consecutive-method-calls-stubbing 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ mockito-consecutive-method-calls-stubbing --- [WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] [INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ mockito-consecutive-method-calls-stubbing --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ mockito-consecutive-method-calls-stubbing --- [WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] [INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ mockito-consecutive-method-calls-stubbing --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ mockito-consecutive-method-calls-stubbing ---
------------------------------------------------------- T E S T S ------------------------------------------------------- Running com.logicbig.example.ProcessorTest My Integer is: 10 My Integer is: 20 Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.678 sec
Results :
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 3.728 s [INFO] Finished at: 2020-04-21T23:53:38-05:00 [INFO] ------------------------------------------------------------------------
Using doReturn-when
mockito-defining-return-values-by-method-stubbing/src/test/java/com/logicbig/example/ProcessorTest2.javapackage com.logicbig.example;
import org.junit.Assert;
import org.junit.Test;
import org.mockito.Mockito;
public class ProcessorTest2 {
@Test
public void processTest() {
MyService myService = Mockito.mock(MyService.class);
Mockito.doReturn(10).when(myService.doSomething());
MyProcessor myProcessor = new MyProcessor(myService);
String returnedValue = myProcessor.process();
Assert.assertEquals(returnedValue, "My Integer is: 10");
}
}
D:\mockito-consecutive-method-calls-stubbing>mvn test -Dtest="ProcessorTest2" [INFO] Scanning for projects... [INFO] [INFO] ---< com.logicbig.example:mockito-consecutive-method-calls-stubbing >--- [INFO] Building mockito-consecutive-method-calls-stubbing 1.0-SNAPSHOT [INFO] --------------------------------[ jar ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ mockito-consecutive-method-calls-stubbing --- [WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] [INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ mockito-consecutive-method-calls-stubbing --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-resources-plugin:2.6:testResources (default-testResources) @ mockito-consecutive-method-calls-stubbing --- [WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent! [INFO] [INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ mockito-consecutive-method-calls-stubbing --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ mockito-consecutive-method-calls-stubbing ---
------------------------------------------------------- T E S T S ------------------------------------------------------- Running com.logicbig.example.ProcessorTest2 My Integer is: 10 My Integer is: 20 Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.854 sec
Results :
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 3.589 s [INFO] Finished at: 2020-04-21T23:54:29-05:00 [INFO] ------------------------------------------------------------------------
Example ProjectDependencies and Technologies Used: - mockito-core 3.3.3: Mockito mock objects library core API and implementation.
- junit 4.13: JUnit is a unit testing framework for Java, created by Erich Gamma and Kent Beck.
- JDK 8
- Maven 3.5.4
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