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Java Unit Testing in Java How to Test Single Assertions Make For Better Tests

Posted by Brandon Johnson
Brandon Johnson
900 Points

sorry Im confused about the whole thing.......I dont even know where Im at Oh **** I need help please

just explain to me whats going on......tell me whats whats

com/teamtreehouse/vending/CreditorTest.java 
package com.teamtreehouse.vending;

import org.junit.Test;

import static org.junit.Assert.*;

public class CreditorTest {

    @Test
    public void addingFundsIncrementsAvailableFunds(0) throws Exception {
        Creditor creditor = new Creditor();

        creditor.addFunds(25);
        creditor.addFunds(25);

        assertEquals(50, creditor.getAvailableFunds(0));
    }

    @Test
    public void refundingReturnsAllAvailableFunds(0) throws Exception {
        Creditor creditor = new Creditor();
        creditor.addFunds(10);

        int refund = creditor.refund(10);

        assertEquals(10, refund);
        assertEquals(0, creditor.getAvailableFunds());
    }
}
com/teamtreehouse/vending/Creditor.java 
package com.teamtreehouse.vending;

public class Creditor {
    private int funds;

    public Creditor(0) {
        funds = 0;
    }

    public void addFunds(int money) {
        funds += money;
    }

    public void deduct(int money) throws NotEnoughFundsException {
        if (money > funds) {
            throw new NotEnoughFundsException(0);
        }
        funds -= money;
    }

    public int refund(0) {
        int refund = funds;
        funds = 0;
        return refund;
    }

    public int getAvailableFunds(0) {
        return funds;
    }

}
Jennifer Nordell
seal-mask
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher
Jennifer Nordell
.a{fill-rule:evenodd;}techdegree
Jennifer Nordell
Treehouse Teacher

Hi there! Treehouse moderator here. I've edited the title of your question. Please refrain from using profanity in the Community. Thank you! :sparkles:

Brandon Johnson
Brandon Johnson
900 Points

O okay cuhhhh!!!

4 Answers

Philip Gales
Philip Gales
15,193 Points

Very confusing what they are asking, but here is my interpretation.

Now that we know that we should only have one behavior that we are asserting per test, can you help me break out the refundingReturnsAllAvailableFunds test case into a new one?

This tells me we are working with the refundingReturnsAllAvailableFunds() method in the CreditorTest class and that we are creating a new method so we can 'only have one behavior that we are asserting per test'.

How about making a new test that does the same, Arrange, Act and Assert named refundingResetsAvailableFundsToZero that separates out that final assertion in the first test.

Tells me to

  • 'making a new test' -----> (create a new class)
  • 'that does the same' -----> (use the same Arrange, Act and Assert)
  • 'named refundingResetsAvailableFundsToZero' -----> (new method is named refundingResetsAvailableFundsToZero ())

The final code looks like this.

package com.teamtreehouse.vending;

import org.junit.Test;

import static org.junit.Assert.*;

public class CreditorTest {

    @Test
    public void addingFundsIncrementsAvailableFunds() throws Exception {
        Creditor creditor = new Creditor();

        creditor.addFunds(25);
        creditor.addFunds(25);

        assertEquals(50, creditor.getAvailableFunds());
    }

    @Test
    public void refundingReturnsAllAvailableFunds() throws Exception {
        Creditor creditor = new Creditor();
        creditor.addFunds(10);

        int refund = creditor.refund();

        assertEquals(10, refund);
        assertEquals(0, creditor.getAvailableFunds());
    }

    @Test
    public void refundingResetsAvailableFundsToZero() throws Exception { //<----new method
        Creditor creditor = new Creditor();
        creditor.addFunds(10);

        int refund = creditor.refund();

        assertEquals(10, refund);
        assertEquals(0, creditor.getAvailableFunds()); 
    }
}
Brandon Johnson
Brandon Johnson
900 Points

good looking out Philip

Jeff Chiu
Jeff Chiu
465 Points
Jeff Chiu
Jeff Chiu
465 Points

thanks for the explanation.

charles wachera
charles wachera
100 Points
charles wachera
charles wachera
100 Points

thanks man,,i was stuck too,, buh thanks to you,,, am a little beeter,,cheers man

ASHLEY H
ASHLEY H
4,408 Points
ASHLEY H
ASHLEY H
4,408 Points

I appreciate the help Philip!