HW-09-Advanced-Multithreading/src/test/java/banking/BankAccountConcurrentDepositTest.java

package banking;

import dev.banking.model.BankAccount;
import org.junit.jupiter.api.Test;

import java.util.concurrent.*;

import static org.junit.jupiter.api.Assertions.assertEquals;

public class BankAccountConcurrentDepositTest {

    @Test
    void concurrentDeposits() throws Exception {

        BankAccount account = new BankAccount(1, 0);

        int threads = 100;
        int perThread = 1000;

        ExecutorService executor = Executors.newFixedThreadPool(threads);
        CountDownLatch latch = new CountDownLatch(threads);

        for (int i = 0; i < threads; i++) {
            executor.submit(() -> {
                for (int j = 0; j < perThread; j++) {
                    account.deposit(1);
                }
                latch.countDown();
            });
        }

        latch.await();
        executor.shutdown();

        assertEquals(threads * perThread, account.getBalance());
    }
}