Spring Boot & H2 - Unit Test Controller

Overview

As in previous chapter we've completed our REST APIs. Now let's create the following structure in src/main/test folder.

• com.tutorialspoint.controller.EmployeeControllerTest − A Unit Tester Class to unit test all methods of EmployeeController.

• com.tutorialspoint.repository.EmployeeRepositoryTest − A Unit Tester Class to unit test all methods of EmployeeRepository.

• com.tutorialspoint.service.EmployeeServiceTest − A Unit Tester Class to unit test all methods of EmployeeService.

SprintBootH2ApplicationTests class is already present. We need to create the above packages and relevant classes.

EmployeeControllerTest

To test a REST Controller, we need the following annotation and classes −

• @ExtendWith(SpringExtension.class) − Mark the class to run as test case using SpringExtension class.

• @SpringBootTest(classes = SprintBootH2Application.class) − Configure the Spring Boot application.

• @AutoConfigureMockMvc − To automatically configure the MockMVC to mock HTTP Requests and Response.

• @Autowired private MockMvc mvc; − MockMvc object to be used in testing.

• @MockBean private EmployeeController employeeController − EmployeeController mock object to be tested.

EmployeeControllerTest.java

Following is the complete code of EmployeeControllerTest class.

package com.tutorialspoint.controller;

import static org.hamcrest.core.Is.is;
import static org.mockito.BDDMockito.given;
import static org.mockito.Mockito.doNothing;
import static org.springframework.http.MediaType.APPLICATION_JSON;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.delete;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.put;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.jsonPath;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

import java.util.ArrayList;
import java.util.List;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.test.web.servlet.MockMvc;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.tutorialspoint.entity.Employee;
import com.tutorialspoint.springboot_h2.SpringbootH2Application;

@SpringBootTest(classes = SpringbootH2Application.class)
@AutoConfigureMockMvc
public class EmployeeControllerTest {
   
   @Autowired
   private MockMvc mvc;
   
   @MockBean
   private EmployeeController employeeController;
   
   @Test
   public void testGetAllEmployees() throws Exception {
      Employee employee = getEmployee();
      List<Employee> employees = new ArrayList<>();
      employees.add(employee);
      given(employeeController.getAllEmployees()).willReturn(employees);
      mvc.perform(get("/emp/employees").contentType(APPLICATION_JSON)).andExpect(status().isOk())
         .andExpect(jsonPath("$[0].name", is(employee.getName())));
   }
   
   @Test
   public void testGetEmployee() throws Exception {
      Employee employee = getEmployee();
      given(employeeController.getEmployee(1)).willReturn(employee);
      mvc.perform(get("/emp/employee/" + employee.getId()).contentType(APPLICATION_JSON)).andExpect(status().isOk())
         .andExpect(jsonPath("name", is(employee.getName())));
   }
   
   @Test
   public void testDeleteEmployee() throws Exception {
      Employee employee = getEmployee();
      doNothing().when(employeeController).deleteEmployee(1);
      mvc.perform(delete("/emp/employee/" + employee.getId()).contentType(APPLICATION_JSON))
         .andExpect(status().isOk()).andReturn();
   }
   
   @Test
   public void testAddEmployee() throws Exception {
      Employee employee = getEmployee();
      doNothing().when(employeeController).addEmployee(employee);
      mvc.perform(post("/emp/employee").content(asJson(employee)).contentType(APPLICATION_JSON))
         .andExpect(status().isOk()).andReturn();
   }
   
   @Test
   public void testUpdateEmployee() throws Exception {
      Employee employee = getEmployee();
      doNothing().when(employeeController).updateEmployee(employee);
      mvc.perform(put("/emp/employee").content(asJson(employee)).contentType(APPLICATION_JSON))
         .andExpect(status().isOk()).andReturn();
   }
   
   private Employee getEmployee() {
      Employee employee = new Employee();
      employee.setId(1);
      employee.setName("Mahesh");
      employee.setAge(30);
      employee.setEmail("mahesh@test.com");
      return employee;
   }
   
   private static String asJson(final Object obj) {
      try {
         return new ObjectMapper().writeValueAsString(obj);
      } catch (Exception e) {
         throw new RuntimeException(e);
      }
   }
}

Run the test cases.

Run the Test cases using Run As > Maven Test.

[INFO] Scanning for projects...
...
[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running com.tutorialspoint.controller.[1mEmployeeControllerTest[m
21:03:09.324 [main] INFO org.springframework.boot.devtools.restart.RestartApplicationListener -- Restart disabled due to context in which it is running

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/

 :: Spring Boot ::                (v3.5.6)

2025-10-01T21:03:09.662+05:30  INFO 46276 --- [springboot-h2] [           main] c.t.controller.EmployeeControllerTest    : Starting EmployeeControllerTest using Java 21.0.6 with PID 46276 (started by mahes in D:\Projects\springboot-h2)
2025-10-01T21:03:09.663+05:30  INFO 46276 --- [springboot-h2] [           main] c.t.controller.EmployeeControllerTest    : No active profile set, falling back to 1 default profile: "default"
2025-10-01T21:03:10.282+05:30  INFO 46276 --- [springboot-h2] [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2025-10-01T21:03:10.326+05:30  INFO 46276 --- [springboot-h2] [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 33 ms. Found 1 JPA repository interface.
...
2025-10-01T21:03:15.338+05:30  INFO 46276 --- [springboot-h2] [           main] c.t.s.SpringbootH2ApplicationTests       : Started SpringbootH2ApplicationTests in 0.48 seconds (process running for 7.078)
[INFO] [1;32mTests run: [0;1;32m1[m, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.511 s -- in com.tutorialspoint.springboot_h2.[1mSpringbootH2ApplicationTests[m
[INFO] 
[INFO] Results:
[INFO] 
[INFO] [1;32mTests run: 6, Failures: 0, Errors: 0, Skipped: 0[m
[INFO] 
[INFO] [1m------------------------------------------------------------------------[m
[INFO] [1;32mBUILD SUCCESS[m
[INFO] [1m------------------------------------------------------------------------[m
[INFO] Total time:  10.893 s
[INFO] Finished at: 2025-10-01T21:03:15+05:30
[INFO] [1m------------------------------------------------------------------------[m