Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Unit Testing in Java How to Test Using Before to not repeat yourself

Saud ALQahtani
Saud ALQahtani
7,842 Points
Posted by Saud ALQahtani
Saud ALQahtani
7,842 Points

I've started the shell for the @Before fixture for these tests. See how the Arrange part is duplicated in both tests, ca

I need help i tried everything.. it's not working....

I need a clear answer.

com/example/CalculatorTest.java 
package com.example;

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

import static org.junit.Assert.*;

public class CalculatorTest {
// declare a Calculator here - don't assign anything to it
    @Before
    public void setUp() throws Exception {
     calculator = new Calculator(); // perfect! 
    }

    @Test
    public void addingMultipleNumbersProducesResult() throws Exception {
        Calculator calculator = new Calculator(); // remove this, you've already done it

        int answer = calculator.addNumbers(1 ,2, 3);

        assertEquals(6, answer);
    }

    @Test
    public void addingSingleNumberTotalsAppropriately() throws Exception {
        Calculator calculator = new Calculator(); // remove this - you've already done it

        int answer = calculator.addNumbers(1);

        assertEquals(1, answer);
    }
}

2 Answers

Steve Hunter
Steve Hunter
57,712 Points
Steve Hunter
Steve Hunter
57,712 Points

Hi there,

At the top of the class create a Calculator-sized hole in memory by declaring a Calculator called calculator. Nothing else. Do this before the setUp() method.

Then, initialize it inside the @Before block with calculator = new Calculator();. Then remove the duplicated lines from the tests; just use the calculator within those.

I've added some comments in your code.

Make sense?

Steve.

Aakriti shrestha
Aakriti shrestha
3,159 Points
Aakriti shrestha
Aakriti shrestha
3,159 Points

package com.example;

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

import static org.junit.Assert.*;

public class CalculatorTest { private Calculator calculator; @Before public void setUp() throws Exception { calculator = new Calculator(); }

@Test
public void addingMultipleNumbersProducesResult() throws Exception {


    int answer = calculator.addNumbers(1 ,2, 3);

    assertEquals(6, answer);
}

@Test
public void addingSingleNumberTotalsAppropriately() throws Exception {


    int answer = calculator.addNumbers(1);

    assertEquals(1, answer);
}

}