Question

Junit testing case

Here are my methods I want to test.

Scanner scan = new Scanner(System.in).useDelimiter("\n");

public String prompt_FirstName() {
    System.out.println("First Name:");
    String firstName = scan.next();
    return firstName;
}

Here's what i have so far

@Test
public void testPrompt_first()
{
    Menu inputOutput= new Menu();

    String input = "Jane";
    InputStream in = new ByteArrayInputStream(input.getBytes());
    System.setIn(in);

    String s = inputOutput.prompt_FirstName();
    assertEquals("Jane", s);
}

Answer 1

Note: Done accordingly. Please comment for any problem. Please Uprate. Thanks

Menu.java

import java.util.Scanner;

public class Menu {
   Scanner scan = new Scanner(System.in).useDelimiter("\n");
  
   public String prompt_FirstName() {
   System.out.println("First Name:");
   String firstName = scan.next();
   return firstName;
   }
}

testCaseIO.java

import static org.junit.Assert.*;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.io.PrintStream;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class testCaseIO {

       //variable for input and print Stream
       private final InputStream systemIn = System.in;
   private final PrintStream systemOut = System.out;

   //variables for ByteArrayInput
   private ByteArrayInputStream testInputStream;
   private ByteArrayOutputStream testOutputStream;
  
   //setting up initial output
   @Before
   public void setUpOutput() {
   testOutputStream = new ByteArrayOutputStream();
   System.setOut(new PrintStream(testOutputStream));
   }

   //getting automatic input
   private void setForAutoInput(String data) {
   testInputStream = new ByteArrayInputStream(data.getBytes());
   System.setIn(testInputStream);
   }

  
   //After execution restore previous input and output
   @After
   public void restoreSystemInputOutput() {
   System.setIn(systemIn);
   System.setOut(systemOut);
   }

   //Testing for positive case
   @Test
   public void testCasePass() {
   final String input = "Jane";
   setForAutoInput(input);
   Menu obj=new Menu();
   String output=obj.prompt_FirstName();
   assertEquals(input, output);
   }
  
   //testing for negative case
   @Test
   public void testCaseFail() {
   final String input = "Jane";
   setForAutoInput(input);
   Menu obj=new Menu();
  
   String output=obj.prompt_FirstName();
   assertNotEquals(input, output+"no");
   }
   }

Output: