AbstractAccountTest.java

package com.luxoft.bankapp.model;

import org.junit.Test;

import static org.junit.Assert.*;

public class AbstractAccountTest {
    // dummy class for testing purpose
    // there is no logic inside.
    // I want test AbstractAccount not TestingAccount
    private class TestingAccount extends AbstractAccount {
        public TestingAccount(float balance) {
            super(balance);
        }

        public TestingAccount() {
            super();
        }
    }

    // SUT - Subject Under Test
    private TestingAccount sut;

    // this is a test
    @Test
    public void testSetBalanceInConstructor() {
        // create new object of TestingAccount
        // this is very important to create new object for any test
        sut = new TestingAccount(1.0f);
        
        // check functionality
        assertEquals(1.0f, sut.getBalance(), 0);
    }

    @Test
    public void testSetBalanceToZeroByDefault() {
        sut = new TestingAccount();

        assertEquals(0.0f, sut.getBalance(), 0);
    }

    @Test
    public void testDepositIncreaseBalance() {
        sut = new TestingAccount(1.0f);
        sut.deposit(2.0f);
        // please read about assertEquals for floating point arguments
        assertEquals(3.0f, sut.getBalance(), 0.00001f);
    }

    // this is a way to test exceoption
    @Test(expected = IllegalArgumentException.class)
    public void testNegativeDepositThrowsException() {
        sut = new TestingAccount();
        sut.deposit(-1.0f);
    }

    @Test(expected = IllegalArgumentException.class)
    public void testZeroDepositThrowsException() {
        sut = new TestingAccount();
        sut.deposit(0.0f);
    }

    @Test(expected = IllegalArgumentException.class)
    public void testNegativeThrowsException() {
        sut = new TestingAccount(-1);
    }
}