Skip to main content

Mock unit testing with Mockito and Spring (Ejb and Rest service)

In this tutorial we are going to learn about mock unit testing. We are using here Mockito with Spring to write unit tests. We will also see how to mock an EJB session bean inside mocked service without constructor/setters injection.

What is mocking

Mocking is a technique to replace the actual implementation with some dummy or provided code chunk during unit testing. For example if we need to unit test some service which persist data to database then we can mock that persist method to add it to some in-memory collection. Also we can mock data retrieval to get the data from same collection or so. Mockito provide various class and features to implement the mocking seamlessly.

Maven dependency

We are using Spring (XML base configuration) and mockito for mock testing. Below dependencies are required.

Spring configuration XML

Below is our configuration for spring where we enable annotation based processing. Also we are creating a bean for EJB session bean.
  1. Spring namespace and schema declaration

  2. <beans xmlns=""
  3. Configure annotation processing

  4.     <context:component-scan base-package=""/>
        <context:component-scan base-package="com.ttj.misc"/>
  5. Bean declaration for EJB Session Bean

  6.     <jee-local-slsb id="ejbSessionBean" jndi-name="ejb/MyEjbSessionBean"
            business-interface="com.ttj.ejb.MyBusinessInterface" />

Rest Service

Below is the Rest service where we inject the ejb session bean using business interface. We invoke the method on EJB bean and then return the same response as a service call response.
public class MyController{
    private MyBusinessInterface ejbSessionBean;

    @RequestMapping(value="/message", method=RequestMethod.GET,
    public String getUserMessageFromEjb(){
        return ejbSessionBean.getUserMessage();

Unit Test using Mockito

Now we will create out unit test using mockito where we will mock the EJB session bean which will be injected in Rest service. Then this rest service will use mocked ejb bean to provide the response.
  1. Required annotations

  2. Here we are using @RunWith annotation to enable the Spring's dependency injection and @ContextConfiguration to makes Spring to scan mentioned classes. Please note that Spring will not load context configuration XML from WEB-INF by default, so we need to configure the scanning of required classes.
    @ContextConfiguration(class={MyController.class, MyControllerTest.class})
    public class MyControllerTest{
  3. Mocking EJB bean

  4. In below code we are creating a mocked bean which will automatically bind with controller class as controller class binds it using the bean ID.
        public MyBusinessInterface ejbSessionBean(){
            MyBusinessInterface bean = Mockito.mock(MyBusinessInterface.class);
            Mockito.when(bean.getUserMessage()).thenReturn("Dummy message");
            return bean;
  5. Writing Test case

  6. In below code we autowire the controller class and then uses it to write the unit test.
        private MyController controller;
        public void getUserMessageFromEjbTest(){
            String exp = "Dummy message");
            Assert.assertEquals(exp, controller.getUserMessageFromEjb());
Now you can execute the maven build to run the test.


Popular Posts

SpringBoot - @ConditionalOnProperty example for conditional bean initialization

@ConditionalOnProperty annotation is used to check if specified property available in the environment or it matches some specific value so it can control the execution of some part of code like bean creation. It may be useful in many cases for example enable/disable service if specific property is available. Below are the attributes which can be used for property check.
havingValue - Provide the value which need to check against specified property otherwise it will check that value should not be false.matchIfMissing - If true it will match the condition and execute the annotated code when property itself is not available in - Name of the property to be tested. If you want to test single property then you can directly put the property name as string like "" and if you have multiple properties to test then you can put the names like {"prop.name1","prop.name2"}prefix - It can be use when you want to apply some prefix to all prop…

Asynchronous REST service implementation in Spring boot

In this tutorial we will see how to create an asynchronous REST service endpoint using Spring boot application.
Asynchronous service works in a way that it will not block the client request and do the processing in separate thread. When work is complete the response returned to the client so our service will be able to handle more client requests at the same time, compare to synchronous processing model.
Let's understand how it is working in synchronous mode. In such server/client application at server side it has a pool of threads which are serving the request. If a request received by a thread then it will be blocked until it send the response back to client. In this case if processing doesn't take much time it will be able to process it quickly and accept other client requests but there could be one situation when all threads are busy and not able to accept the new client requests.

To overcome of such problems, asynchronous processing model introduced for REST services. In…

Entity to DTO conversion in Java using Jackson

It's very common to have the DTO class for a given entity in any application. When persisting data, we use entity objects and when we need to provide the data to end user/application we use DTO class. Due to this we may need to have similar properties on DTO class as we have in our Entity class and to share the data we populate DTO objects using entity objects. To do this we may need to call getter on entity and then setter on DTO for the same data which increases number of code line. Also if number of DTOs are high then we need to write lot of code to just get and set the values or vice-versa.
To overcome this problem we are going to use Jackson API and will see how to do it with minimal code only.
Maven dependency <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.9.9</version> </dependency> Entity class Below is our ent…

Web scraper using JSoup and Spring Boot

What is webscraping Webscraping is a technique to extract or pull the data from a website to gather required information by parsing the HTML source of their websites, such as articles from news or books site, products information from online shopping sites or course information from education sites. There are many organisations who uses web scraper to provide the best experience to their customers, for example extract the price for a smartphone from multiple online websites and show their customers the best and cheap product URL.
We will learn here how to code a web scraper by developing a simple new scraper service.
News scraper News scraper is used to extract the news articles or other related contents from a news site. Here we are going to create a web scraper application to pull the articles from news site.
Below are the operations provided by our news scraper service.
List all the authorsSearch articles by author nameSearch articles by article titleSearch articles by article desc…