Unable to write test case in Junit 5 - spring-boot

Question

This is my Globalexceptionhandlerclass.java. I am trying to write JUnit 5 test cases, but getting stuck. Can anyone help me on this please?
Globalexceptionhandlerclass.java
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.context.request.WebRequest;
import org.springframework.web.servlet.mvc.method.annotation.ResponseEntityExceptionHandler;
public class GlobalExceptionHandler extends ResponseEntityExceptionHandler {
protected final Log loger = LogFactory.getLog(ResponseEntityExceptionHandler.class);
#ExceptionHandler(Exception.class)
ResponseEntity<?> handleAllExceptions(Exception ex, WebRequest request ) {
Map<String, Object> result = new HashMap<String, Object>();
result.put("date", new Date());
result.put("message", ex.getMessage());
result.put("details", request.getDescription(true));
loger.error(ex);
ResponseEntity<?> responseEntity = ResponseEntity.badRequest()
.header("exception-erro", "error")
.body(result);
return responseEntity;
}
}
This is my GlobalExceptionHandlerTest.java. I got stuck on this, it is failing. I tried other things but it is not working. The last two lines are failing, I don't know why. Anyone please help me to corect this cases. It will be very helpful to me.
import javax.servlet.http.HttpServletRequest;
#ExtendWith(MockitoExtension.class)
class ExceptionHandlerControllerAdviceTest {
/**
* Given a handle invalid exception when controller advice then return a bad request exception.
*/
#Test
void handleInvalidFormatException() {
GlobalExceptionHandler controllerAdvice = new GlobalExceptionHandler();
ResponseEntity<?> response = controllerAdvice.handleAllExceptions(null, null);
assertEquals(HttpStatus.BAD_REQUEST.value(), response.getStatusCode().value());
}
}

Answer 1

handleAllExceptions is not null-safe because of this line result.put("message", ex.getMessage()); and you passing ex with null value in your test controllerAdvice.handleAllExceptions(null, null).
This test has no reason to be because Spring always provides you Exception and WebRequest. So calling handleAllExceptions(null, null) is not possible in Spring environment.