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

praveen gudimetla
praveen gudimetla
464 Points
Posted by praveen gudimetla
praveen gudimetla
464 Points

CalculatorTest JUnit issues

Hi,

I tried my test class as below. I get error Bummer! please only intitialze Calculator once in Before Gags. how to fix this error. please advuse

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 {

//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/CalculatorTest.java 
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 {

 //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;
    }
}

5 Answers

AJ Longstreet
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
AJ Longstreet
Treehouse Project Reviewer
AJ Longstreet
.a{fill-rule:evenodd;}techdegree seal-36
AJ Longstreet
Treehouse Project Reviewer

You actually did it correctly but tests can be finicky.

Delete the commented code (//Calculator calculator = new Calculator();) and you will be on to the next one!!

praveen gudimetla
praveen gudimetla
464 Points
praveen gudimetla
praveen gudimetla
464 Points

package com.example;

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

import static org.junit.Assert.*; Calculator calculator; public class CalculatorTest {

@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);
}

}

i removed commented lines as above getting compilation errors like

./com/example/CalculatorTest.java:7: error: class, interface, or enum expected Calculator calculator; ^ ./com/example/CalculatorTest.java:13: error: cannot find symbol calculator=new Calculator(); ^ symbol: variable calculator location: class CalculatorTest ./com/example/CalculatorTest.java:21: error: cannot find symbol int answer = calculator.addNumbers(1 ,2, 3); ^ symbol: variable calculator location: class CalculatorTest ./com/example/CalculatorTest.java:30: error: cannot find symbol int answer = calculator.addNumbers(1); ^ symbol: variable calculator location: class CalculatorTest 4 errors

please advise

praveen gudimetla
praveen gudimetla
464 Points
praveen gudimetla
praveen gudimetla
464 Points

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 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);
}

}

above gives below error Bummer! There is a compiler error. Please click on preview to view your syntax errors!

AJ Longstreet
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
AJ Longstreet
Treehouse Project Reviewer
AJ Longstreet
.a{fill-rule:evenodd;}techdegree seal-36
AJ Longstreet
Treehouse Project Reviewer

You just need to declare it in the global scope and instantiate it in the @Before. Then delete the other 2 declarations and you're golden.

This code passes.

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);
    }
}