Spring boot: integration tests to service layer

In Integration testing, Software modules which are logically connected are tested as a group. For example, in any typical business applications, there are three layers.

a.   Controller Layer: Controller layer is responsible for receiving the user request and sending the responses.

b.   Service layer: It performs some logic to operate on the data sent to and from the DAO.

c.    Dao Layer: It performs plain CRUD operations against a database.

In this post, I am going to show you how to write integration tests to service layer.

Step 1: Create a service test class and annotate with test specific annotations.

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
public class EmployeeServiceTest {

 .....
 .....

}

@RunWith(SpringJUnit4ClassRunner.class)

This statement tell to Junit to invoke the test cases using 'SpringJUnit4ClassRunner' class.

@SpringBootTest(webEnvironment=WebEnvironment.NONE)

This annotation specify that we are running spring boot application tests and we are not testing controller layer.

Step 2: Inject EmployeeService instance to test class.

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
public class EmployeeServiceTest {
 
 @Autowired
 EmployeeService empService;

 ......
 ......
}

Step 3: Write test method that execute service class methods and test against the results.

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
public class EmployeeServiceTest {
 
 @Autowired
 EmployeeService empService;
 
 @Test
 public void newEmployee() {
  Employee emp1 = new Employee();
  emp1.setFirstName("Anil");
  emp1.setLastName("Kumar");
  
  Employee persistedEmployee = empService.save(emp1);
  
  assertNotNull(persistedEmployee);
  assertNotNull(persistedEmployee.getId());
  assertEquals(emp1.getFirstName(), persistedEmployee.getFirstName());
  assertEquals(emp1.getLastName(), persistedEmployee.getLastName());
 }

}

Find the below working application.

Employee.java

package com.sample.app.model;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "employees")
public class Employee {

 @Id
 @GeneratedValue
 @Column(name = "employee_name")
 private Integer id;

 @Column(name = "first_name")
 private String firstName;

 @Column(name = "last_name")
 private String lastName;

 public Integer getId() {
  return id;
 }

 public void setId(Integer id) {
  this.id = id;
 }

 public String getFirstName() {
  return firstName;
 }

 public void setFirstName(String firstName) {
  this.firstName = firstName;
 }

 public String getLastName() {
  return lastName;
 }

 public void setLastName(String lastName) {
  this.lastName = lastName;
 }

}

EmployeeDao.java

package com.sample.app.dao;

import java.util.List;

import com.sample.app.model.Employee;

public interface EmployeeDao {

 public Employee save(Employee emp);
 
 public List<Employee> all();
}

EmployeeDaoImpl.java

package com.sample.app.dao.impl;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import com.sample.app.dao.EmployeeDao;
import com.sample.app.model.Employee;

@Repository
public class EmployeeDaoImpl implements EmployeeDao {
 @PersistenceContext
 private EntityManager entityManager;

 @Override
 @Transactional
 public Employee save(Employee emp) {
  entityManager.persist(emp);
  entityManager.flush();
  int id = emp.getId();

  return entityManager.find(Employee.class, id);

 }

 @Override
 public List<Employee> all() {
  Query query = entityManager.createQuery("select e from Employee e", Employee.class);
  return query.getResultList();
 }

}

EmployeeService.java

package com.sample.app.service;

import java.util.List;

import com.sample.app.model.Employee;

public interface EmployeeService {
 public Employee save(Employee emp);

 public List<Employee> all();
}

EmployeeServiceImpl.java

package com.sample.app.service.impl;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.sample.app.dao.EmployeeDao;
import com.sample.app.model.Employee;
import com.sample.app.service.EmployeeService;

@Service
public class EmployeeServiceImpl implements EmployeeService {

 @Autowired
 EmployeeDao empDao;

 @Override
 public Employee save(Employee emp) {
  return empDao.save(emp);
 }

 @Override
 public List<Employee> all() {
  return empDao.all();
 }

}

HomeController.java

package com.sample.app.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HomeController {
 @RequestMapping("/")
 public String homePage() {
  return "Welcome to Spring boot Application Development";
 }

}

EmployeeController.java

package com.sample.app.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.sample.app.model.Employee;
import com.sample.app.service.EmployeeService;

@RestController
@RequestMapping("api/v1/")
public class EmployeeController {

 @Autowired
 private EmployeeService empService;

 @RequestMapping(value = "employees", method = RequestMethod.GET)
 public ResponseEntity<List<Employee>> allEmployees() {
  return ResponseEntity.ok(empService.all());
 }

 @RequestMapping(value = "employees", method = RequestMethod.POST)
 public ResponseEntity<Employee> save(@RequestBody Employee emp) {
  Employee persistedEmp = empService.save(emp);
  return ResponseEntity.status(HttpStatus.CREATED).body(persistedEmp);
 }

}

App.java

package com.sample.app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;

@SpringBootApplication
@EnableJpaAuditing
public class App {

 public static void main(String args[]) {
  SpringApplication.run(App.class, args);
 }

}

application.properties

logging.level.root=WARN
logging.level.org.hibernate=ERROR

## H2 specific properties
spring.h2.console.enabled=true
spring.h2.console.path=/h2

spring.datasource.url=jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;

spring.datasource.username=krishna
spring.datasource.password=password123

spring.datasource.driverClassName=org.h2.Driver

## JPA specific properties
# Creates the schema, destroying previous data.
spring.jpa.hibernate.ddl-auto=create

spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

spring.jpa.show-sql=true
spring.jpa.properties.hibernate.format_sql=true

## Database connection pooling properties
# Number of ms to wait before throwing an exception if no connection is available.
spring.datasource.max-wait=10000

# Maximum number of active connections that can be allocated from this pool at the same time.
spring.datasource.tomcat.max-active=10
spring.datasource.tomcat.max-idle=5
spring.datasource.tomcat.min-idle=3

spring.jpa.properties.hibernate.enable_lazy_load_no_trans=true

pom.xml

<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>springTest</groupId>
 <artifactId>springTest</artifactId>
 <version>1</version>


 <parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>2.1.6.RELEASE</version>
 </parent>

 <name>springbootApp</name>
 <url>http://maven.apache.org</url>

 <properties>
  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 </properties>

 <dependencies>

  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
  </dependency>

  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-data-jpa</artifactId>
  </dependency>


  <dependency>
   <groupId>com.h2database</groupId>
   <artifactId>h2</artifactId>
  </dependency>

  <dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-test</artifactId>
   <scope>test</scope>
  </dependency>

 </dependencies>
</project>

Test class is written like below.

EmployeeServiceTest.java

package com.sample.app.service;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.sample.app.model.Employee;

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
public class EmployeeServiceTest {
 
 @Autowired
 EmployeeService empService;
 
 @Test
 public void newEmployee() {
  Employee emp1 = new Employee();
  emp1.setFirstName("Anil");
  emp1.setLastName("Kumar");
  
  Employee persistedEmployee = empService.save(emp1);
  
  assertNotNull(persistedEmployee);
  assertNotNull(persistedEmployee.getId());
  assertEquals(emp1.getFirstName(), persistedEmployee.getFirstName());
  assertEquals(emp1.getLastName(), persistedEmployee.getLastName());
 }

}

Total project structure looks like below.

How to run the test case?

Right click on EmployeeServiceTest.java -> Run As -> Junit Test.

You can able to see test results under Junit tab.

You can download complete working application from this link.

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