Person.java

package com.imrenagi.roboelectric_testing;

public class Person {
    
    public Person(){
    }

    public int add () {
        return 1;
    }
}

PersonTest.java

package com.imrenagi.roboelectric_testing;

import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.robolectric.RobolectricTestRunner;
import org.robolectric.annotation.Config;

@Config(emulateSdk = 18)
@RunWith(RobolectricTestRunner.class)
public class PersonTest {
    Person mPerson;

    @Before
    public void setUp() {
        mPerson = new Person();
    }

    @Test
    public void shouldReturnOne() {
        Assert.assertEquals(1, mPerson.add());
    }
}