Java JUnit Library. Types of Testing

1. Testing in Development

Let's talk about types of testing and which testing methods developers use. You will learn about the stages an application goes through before being delivered to the client and the specific tests you will need to write.

What is Testing, and Why do We Need It

Types of Testing

2. Unit Tests

In this section, we're going to dive into unit testing — you'll get the rundown on its structure in Java and the ins and outs of crafting them the right way. Setting up your IDE, importing necessary libraries, and lots of hands-on practice.

Set-Up

Test-Driven Development

Creating Unit Tests

@BeforeEach

How to Test `void` Methods

Assertions

Assertions Practice

Section 2 Summary

3. Exceptions

In this section, we will enhance our coding skills by dealing with errors that can also be caught in unit tests. When testing an application, you may come across various errors, and sometimes they should be turned into exceptions. I will explain how to catch exceptions in your code, test them, and handle them properly.

Throwing Exceptions

Try-catch structure

Handling Multiple Exceptions

Handling Exceptions Practice

Creating Exceptions

Testing Exceptions

Testing Exceptions Practice

Assertions Practice

It's time to practice with different Assertions. A class has been written for you with some methods. Tests for these methods are already written, but for some reason, they keep failing. Your task is to find out the reason for this. The problem lies in the tests, not the code.

Link to the Task: GitHub

Pay close attention to the expected and actual values. This way, you will understand what needs to be used in a specific test case.

Your goal is to make the tests work, check the assertions for correctness.

Some test cases have two assertions at once; pay attention to that.

You will need to use almost every assertion from the previous chapter, so be attentive.

public class BankTransactionTest {

@Test
    public void testInitialBalancePositive() {
        double initialBalance = 100.0;
        BankTransaction bt = new BankTransaction(initialBalance);
        double expected = 100.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

@Test
    public void testInitialBalanceNegative() {
        double initialBalance = -100.0;
        BankTransaction bt = new BankTransaction(initialBalance);
        double expected = 0.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
        assertNotEquals(initialBalance, actual, 0.001);
    }

@Test
    public void testDeposit() {
        BankTransaction bt = new BankTransaction(100.0);
        double depositAmount = 50.0;
        boolean depositResult = bt.deposit(depositAmount);
        assertTrue(depositResult);

double expected = 150.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

@Test
    public void testDepositNegativeAmount() {
        BankTransaction bt = new BankTransaction(100.0);
        double depositAmount = -50.0;
        boolean depositResult = bt.deposit(depositAmount);
        assertFalse(depositResult);

double expected = 100.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

@Test
    public void testWithdrawSuccessful() {
        BankTransaction bt = new BankTransaction(100.0);
        double withdrawalAmount = 50.0;
        boolean withdrawalResult = bt.withdraw(withdrawalAmount);
        assertTrue(withdrawalResult);

double expected = 50.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

@Test
    public void testWithdrawInsufficientFunds() {
        BankTransaction bt = new BankTransaction(50.0);
        double withdrawalAmount = 100.0;
        boolean withdrawalResult = bt.withdraw(withdrawalAmount);
        assertFalse(withdrawalResult);

double expected = 50.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

@Test
    public void testWithdrawNegativeAmount() {
        BankTransaction bt = new BankTransaction(100.0);
        double withdrawalAmount = -50.0;
        boolean withdrawalResult = bt.withdraw(withdrawalAmount);
        assertFalse(withdrawalResult);

double expected = 100.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

@Test
    public void testNotNullBankTransaction() {
        BankTransaction bt = new BankTransaction(100.0);
        assertNotNull(bt);
    }

@Test
    public void testNullBankTransaction() {
        BankTransaction bt = null;
        assertNull(bt);
    }
}

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Зміст курсу

Java JUnit Library. Types of Testing

Assertions Practice

Link to the Task: GitHub

Pay close attention to the expected and actual values. This way, you will understand what needs to be used in a specific test case.

Your goal is to make the tests work, check the assertions for correctness.

Some test cases have two assertions at once; pay attention to that.

You will need to use almost every assertion from the previous chapter, so be attentive.

public class BankTransactionTest {

double expected = 150.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

double expected = 100.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

double expected = 50.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

double expected = 100.0;
        double actual = bt.getBalance();
        assertEquals(expected, actual, 0.001);
    }

@Test
    public void testNotNullBankTransaction() {
        BankTransaction bt = new BankTransaction(100.0);
        assertNotNull(bt);
    }

@Test
    public void testNullBankTransaction() {
        BankTransaction bt = null;
        assertNull(bt);
    }
}

Все було зрозуміло?

Секція 2. Розділ 7