简单的 JavaJUnit 测试

JUnit 是用于测试 Java 代码的领先测试框架。

被测试的类模拟了一个简单的银行账户，当你透支时收取罚款。

public class BankAccount {
    private int balance;

    public BankAccount(int i){
        balance = i;
    }

    public BankAccount(){
        balance = 0;
    }

    public int getBalance(){
        return balance;
    }

    public void deposit(int i){
        balance += i;
    }

    public void withdraw(int i){
        balance -= i;
        if (balance < 0){
            balance -= 10; // penalty if overdrawn
        }
    }
}

此测试类验证某些 BankAccount 公共方法的行为。

import org.junit.Test;
import static org.junit.Assert.*;

// Class that tests
public class BankAccountTest{

    BankAccount acc;

    @Before                        // This will run **before** EACH @Test
    public void setUptestDepositUpdatesBalance(){
        acc = new BankAccount(100);  
    } 

    @After                        // This Will run **after** EACH @Test
    public void tearDown(){
    // clean up code
    }

    @Test
    public void testDeposit(){
       // no need to instantiate a new BankAccount(), @Before does it for us

        acc.deposit(100);

        assertEquals(acc.getBalance(),200); 
    }

    @Test
    public void testWithdrawUpdatesBalance(){    
        acc.withdraw(30);

        assertEquals(acc.getBalance(),70); // pass
    }

    @Test
    public void testWithdrawAppliesPenaltyWhenOverdrawn(){

        acc.withdraw(120);

        assertEquals(acc.getBalance(),-30);
    }
}