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

Shar Feldheim
Shar Feldheim
142 Points

Declaration I declare a variable in @Before, calculator = new Calculator . There is always a an error, "calculator"

I want to see how it is best done. What is my error?

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

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

import static org.junit.Assert.*;

public class CalculatorTest {
 // void Calculator();
    @Before
    public void setUp() throws Exception {
      calculator = new Calculator();
      int answer = calculator.addnumbers();
    }

    @Test
    public void addingMultipleNumbersProducesResult() throws Exception {
       // calculator = calculator;
new
        int answer = calculator.addNumbers(1 ,2, 3);

        assertEquals(6, answer);
    }

    @Test
    public void addingSingleNumberTotalsAppropriately() throws Exception {
        //Calculator calculator = new Calculator();

        int answer = calculator.addNumbers(1);

        assertEquals(1, answer);
    }
}
com/example/Calculator.java
package com.example;

public class Calculator {

    public int addNumbers(int... numbers) {
        int total = 0;
        for (int number : numbers) {
            total += number;
        }
        return total;
    }
}

1 Answer

Florian Tönjes
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Florian Tönjes
Full Stack JavaScript Techdegree Graduate 50,855 Points

Hi Shar,

you almost got it. You need to declare a calculator field in the calculator test class which you can assign the new calculator to.

public class CalculatorTest {
    private Calculator calculator;

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

Kind Regards, Florian