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

Enyang Mercy
PLUS
Enyang Mercy
Courses Plus Student 2,339 Points
Posted by Enyang Mercy
Enyang Mercy
Courses Plus Student 2,339 Points

Unit Test in java Calculator Test @BeforeMethod

How do i fix the arrange part? I already instantiated a new Calculator in each method. But i can't compile . Can u please identify the error and make corrections. Thanks

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

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

import static org.junit.Assert.*;

public class CalculatorTest {

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

    }

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

        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

Pedro Cabral
Pedro Cabral
33,586 Points
Pedro Cabral
Pedro Cabral
33,586 Points

You have a couple of problems:

  1. In your before method, you declared an object of type Calculator but you did not assign it a variable name.
  2. The point of having the Calculator in the before method is to avoid repetition in your tests, so you can remove those repeated assignments/instantiations as you are meant to initialise the calculator only once.
  3. Once you remove it from your test methods, you need a way to access it, so you should move calculator to a field/property of the class and leave the instantiation in your before method so that it will be available to all tests.