JUnit

JUnit is the easiest and the most preferred testing framework for Java and Spring applications. By writing JUnit test cases for our application, we can improve the quality of our application and also avoid buggy situations.

Here, we will discuss a simple JUnit test case, which is calling the getAllUsers method in userService. We can check the following code:

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserTests {  
  @Autowired
  UserService userSevice;
  @Test
  public void testAllUsers(){
    List<User> users = userSevice.getAllUsers(); 
    assertEquals(3, users.size());
  }
}

In the preceding code, we have called getAllUsers and verified the total count. Let's test the single-user method in another test case:

// other methods
@Test
public void testSingleUser(){
    User user = userSevice.getUser(100); 
    assertTrue(user.getUsername().contains("David"));
}

In the preceding code snippets, we just tested our service layer and verified the business logic. However,...