JUnit, Mockito library, Spring Boot Testing - Yash-777/MyWorld GitHub Wiki

JUNIT

📝 TL;DR

• ✅ Use @RunWith(MockitoJUnitRunner.class) – JUnit 4 Style for JUnit 4
  • You can use only one @RunWith, so you can’t combine it with other runners like Parameterized, etc.
• ✅ Use @ExtendWith(MockitoExtension.class) – JUnit 5 Style for JUnit 5
  • You can combine with other extensions: e.g., @ExtendWith(SpringExtension.class) for Spring Boot testing.
• ❌ Don't use both together — they serve the same purpose but for different frameworks

Squaretest - Java Unit Test Generator for IntelliJ IDEA

@Controller public class UserController {
    @Autowired private UserService userService;
    
    public String getUserFullName(int userId) {
        User user = userService.getUserById(userId);
        return user.getFirstName() + " " + user.getLastName();
    }
}
  
@Service
public class MyService {
    public User getUserById(int userId) {
	return User.builder().firstName("Yash").lastName("M").build();
    }

    public int multiplyNumbers(int a, int b) {
        int sum = addNumbers(a, b);
        return a * b * sum;
    }
    private int addNumbers(int a, int b) {
        return a + b;
    }
}

import static org.junit.jupiter.api.Assertions.assertEquals;

@RunWith(MockitoJUnitRunner.class)
@ExtendWith(MockitoExtension.class)
public class MyServiceTest {

    @InjectMocks  // Test Class
    private MyService myService;

    @Test
    public void testMultiplyNumbers() {
	int expected = 30;
	
        int result = myService.multiplyNumbers(2, 3);
        assertEquals(expected, result);
    }
    
    @Test
    public void testAddNumbers() throws Exception {
        int expectedSum = 5;
		
        int sum = (int) ReflectionTestUtils.invokeMethod(myService, "addNumbers", 2, 3);
        assertEquals(expectedSum, sum);
    }
}

---

//String userName = (String) SecurityContextHolder.getContext().getAuthentication().getPrincipal();
private void loggedInUser() { // org.mockito.Mockito
	org.springframework.security.core.context.SecurityContext securityContext = mock(SecurityContext.class);
	org.springframework.security.core.Authentication authentication = 
             mock(org.springframework.security.authentication.UsernamePasswordAuthenticationToken.class);
	when(authentication.getPrincipal()).thenReturn("JUnitTestUser");
	when(securityContext.getAuthentication()).thenReturn(authentication);
	org.springframework.security.core.context.SecurityContextHolder.setContext(securityContext);
}

//Please remove unnecessary stubbings or use 'lenient' strictness. More info: javadoc for UnnecessaryStubbingException class.
private void request(String payLoad) throws java.io.IOException {
    // Mock behavior for HttpServletRequest
    HttpServletRequest request = mock(HttpServletRequest.class);
    JsonRequestWrapper jsonRequestWrapper = new JsonRequestWrapper(request, payLoad);
    ServletInputStream servletInputStream = jsonRequestWrapper.getInputStream();
    lenient().when(request.getInputStream()).thenReturn(servletInputStream);
}

public class JsonRequestWrapper extends HttpServletRequestWrapper {
    private final String jsonRequestBody;
    public JsonRequestWrapper(HttpServletRequest request, String jsonRequestBody) {
        super(request); this.jsonRequestBody = jsonRequestBody;
    }
    @Override
    public ServletInputStream getInputStream() throws IOException {
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(jsonRequestBody.getBytes());
        return new ServletInputStream() {
            public int read() throws IOException {
                return byteArrayInputStream.read();
            }
            @Override
            public boolean isFinished() {
                return false;
            }
            @Override
            public boolean isReady() {
                return true;
            }
            @Override
            public void setReadListener(ReadListener readListener) {
                // Implement as needed
            }
        };
    }
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }
}