03. Bank Account

using NUnit.Framework;
using System;

namespace TestApp.Tests
{
    [TestFixture]
    public class BankAccountTests
    {
        [Test]
        public void Test_Constructor_InitialBalanceIsSet()
        {
            // Arrange
            double initialBalance = 100.0;

            // Act
            BankAccount account = new BankAccount(initialBalance);

            // Assert
            Assert.AreEqual(initialBalance, account.Balance);
        }

        [Test]
        public void Test_Deposit_PositiveAmount_IncreasesBalance()
        {
            // Arrange
            BankAccount account = new BankAccount(100.0);
            double depositAmount = 50.0;

            // Act
            account.Deposit(depositAmount);

            // Assert
            Assert.AreEqual(150.0, account.Balance);
        }

        [Test]
        public void Test_Deposit_NegativeAmount_ThrowsArgumentException()
        {
            // Arrange
            BankAccount account = new BankAccount(100.0);
            double depositAmount = -50.0;

            // Act & Assert
            Assert.Throws<ArgumentException>(() => account.Deposit(depositAmount), "Deposit with negative amount should throw an ArgumentException.");
        }

        [Test]
        public void Test_Withdraw_ValidAmount_DecreasesBalance()
        {
            // Arrange
            BankAccount account = new BankAccount(100.0);
            double withdrawAmount = 50.0;

            // Act
            account.Withdraw(withdrawAmount);

            // Assert
            Assert.AreEqual(50.0, account.Balance);
        }

        [Test]
        public void Test_Withdraw_NegativeAmount_ThrowsArgumentException()
        {
            // Arrange
            BankAccount account = new BankAccount(100.0);
            double withdrawAmount = -50.0;

            // Act & Assert
            Assert.Throws<ArgumentException>(() => account.Withdraw(withdrawAmount), "Withdraw with negative amount should throw an ArgumentException.");
        }

        [Test]
        public void Test_Withdraw_AmountGreaterThanBalance_ThrowsArgumentException()
        {
            // Arrange
            BankAccount account = new BankAccount(100.0);
            double withdrawAmount = 150.0;

            // Act & Assert
            Assert.Throws<ArgumentException>(() => account.Withdraw(withdrawAmount), "Withdraw with amount greater than balance should throw an ArgumentException.");
        }
    }
}