package ru.job4j;

import org.junit.Test;
import static org.hamcrest.core.Is.is;
import static org.junit.Assert.*;


public class CalculateTest {
    @Test
    public void whenSetStopInEchoThenReturnThreeStops() {
       
        Calculate calc = new Calculate();
        String result = calc.echo("stop");
        assertThat(result, is("stop stop stop"));
    }
    
     @Test
    public void whenSetNullInEchoThenReturnTowSpaces() {
       
        Calculate calc = new Calculate();
        String result = calc.echo("stop");
        assertThat(result, is("  "));
    }
    
        
    }
   

package ru.job4j;

import org.junit.Test;
import static org.hamcrest.core.Is.is;
import static org.junit.Assert.*;


public class CalculateTest {
    @Test
    public void whenSetStopInEchoThenReturnThreeStops() {
       
        Calculate calc = new Calculate();
        String result = calc.echo("stop");
        assertThat(result, is("stop stop stop"));
    }
    
 }
   

Create CalculateTest.java