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

please explain me this i dont get it

please expalin this coding

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() 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());
    }
}
com/teamtreehouse/vending/Creditor.java
package com.teamtreehouse.vending;

public class Creditor {
    private int funds;

    public Creditor() {
        funds = 0;
    }

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

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

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

    public int getAvailableFunds() {
        return funds;
    }

}

1 Answer

Benjamin Doyle
Benjamin Doyle
9,603 Points

Which part are you having an issue with?

CreditorTest.java contains some junit tests, which test code so that if you continue working on Creditor.java, and the test breaks you know where and how (or a general idea on how) to fix it.

and Creditor.java is the code you are working on.

It is all a part of Test Driven Development, which you can find more info on TT or here: https://en.wikipedia.org/wiki/Test-driven_development