Junit Test for Controller with parameters - spring-boot

Question

Hi I'm trying to write Junit test for a controller but cant seem to find the proper approach can anyone please suggest how could write a junit test case for the following controller:
Contoller Class
public final class Contoller {
private static final Logger logger = LoggerFactory.getLogger(LiabilityContoller.class);
#Autowired
DemoService demoService;
#GetMapping("/report")
public ResponseEntity<String> getCollection(#RequestParam(name="cohort")String cohort){
List<Book> collection=demoService.getRecords(amount);
bookUtils.writeDataIntoCSVFile(collection, amount);
uploadReportsFilesToSftp(amount);
return new ResponseEntity<String>(" Files Are Generated", HttpStatus.OK);
}
Service class:
#Service
public class DemoService{
#Autowired
DemoRepository demoRepository;
public List<Liability> getRecords(String amount) {
List<Book> list=demoRepository.getRecordsByAmount(amount);
return list;
}
}
Repository
public interface DemoRepository extends JpaRepository<Book,Long>{
#Query(value="Select name,amount from Book where amount=:amount",
List<Book>getRecordsByAmount(String amount);
}
Utility:
public static void writeDataIntoReportsCSVFile(final List<Book> collection,final String amount,final String sftpLocalFile) {
try {
FileWriter FileWriter1 = new FileWriter(sftpLocalFile+"demo.csv");
CSVPrinter FilePrinter1 = new CSVPrinter(FileWriter1, CSVFormat.EXCEL);
printReportsHeader(FileWriter1);
for (Liability obj : collection) {
FilePrinter1.printRecord(obj.getName(),obj.getAmount());
}
FilePrinter1.close();
} catch (IOException ex) {
ex.printStackTrace();
}
}
public static void printReportsHeader(CSVPrinter FilePrinter1) {
try {
FilePrinter1.printRecord("NAME","AMOUNT");
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
How could I test this controller what could be the best way to do so?

Answer 1

When you want to unit test a Spring application, the high level idea would be to write tests for the repository layer first, then write unit tests for the service, and then finally the controller layer.
Assuming that you have unit tests for DemoService, bookUtils, and uploadReportsFilesToSftp the Test for the controller would be exactly as below.
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.extension.ExtendWith;
import org.mockito.Mockito;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
import org.springframework.boot.test.mock.mockito.MockBean;
import org.springframework.test.context.junit.jupiter.SpringExtension;
import org.springframework.test.web.servlet.MockMvc;
import static org.mockito.ArgumentMatchers.any;
import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
#ExtendWith(SpringExtension.class)
#WebMvcTest(Controller.class)
class ControllerTest {
#Autowired
private MockMvc mockMvc;
#MockBean
private DemoService jsonFileService;
#Test
void getCollection() throws Exception {
Mockito.doNothing().when(jsonFileService.getRecords(any()));
// similar stubbings here
this.mockMvc.perform(
get("/report")
.param("cohort", "testCohortValue")
).andExpect(
status().isOk()
);
}
}