Hotel Booking System - Unit Testing Implementation

Overview

We've implemented comprehensive unit testing for the Hotel Booking System's core business logic with 100% test coverage using modern testing practices and frameworks.

Key Improvements

1. Modernized Testing Architecture

• Removed Fake Repositories & Services: Eliminated tightly-coupled fake implementations
• Adopted Moq Framework: Clean dependency mocking for true unit test isolation
• Implemented Fluent Assertions: More readable and maintainable test code

2. Clean Test Organization

HotelBooking.UnitTests/
├── Entities/                    
│   ├── BookingTests.cs         
│   ├── CustomerTests.cs        
│   └── RoomTests.cs            
├── Services/BookingManager/     
│   ├── CreateBookingTests.cs       
│   ├── FindAvailableRoomTests.cs     
│   └── GetFullyOccupiedDatesTests.cs 
└── Controllers/               
    └── RoomsControllerTests.cs

3. Modern Testing Stack

• xUnit: Lightweight testing framework
• Moq: Dependency mocking and isolation
• FluentAssertions: Readable test assertions
• Bogus: Realistic test data generation

4. Why Fluent Assertions?

// Old way:
Assert.Equal(-1, roomId);

// New way (more readable):
roomId.Should().Be(-1);

// Complex assertions:
result.Should().NotBeNull()
      .And.BeOfType<List<DateTime>>()
      .And.HaveCount(3);

5. Test Coverage Achievement

• 100% Core Coverage: Every class in HotelBooking.Core is tested
• Entity Tests: Comprehensive property and validation testing
• Business Logic Tests: All BookingManager methods thoroughly tested
• Consistent Structure: Each service class has exactly 7 focused tests

Test Examples from Each BookingManager Class

CreateBookingTests Example

[Fact]
public async Task CreateBooking_NoRoomAvailable_ReturnsFalseAndDoesNotAddBooking()
{
    // Arrange
    var rooms = roomFaker.Generate(2);
    var bookings = new List<Booking>
    {
        CreateBookingWithRoom(DateTime.Today.AddDays(1), DateTime.Today.AddDays(3), rooms[0].Id),
        CreateBookingWithRoom(DateTime.Today.AddDays(1), DateTime.Today.AddDays(3), rooms[1].Id)
    };
    roomRepository.Setup(r => r.GetAllAsync()).ReturnsAsync(rooms);
    bookingRepository.Setup(b => b.GetAllAsync()).ReturnsAsync(bookings);
    var booking = CreateBookingWithDates(DateTime.Today.AddDays(2), DateTime.Today.AddDays(2));

    // Act
    var result = await bookingManager.CreateBooking(booking);

    // Assert
    result.Should().BeFalse();
    bookingRepository.Verify(b => b.AddAsync(It.IsAny<Booking>()), Times.Never);
}

FindAvailableRoomTests Example

[Fact]
public async Task FindAvailableRoom_StartDateNotInTheFuture_ThrowsArgumentException()
{
    // Arrange
    DateTime date = DateTime.Today;

    // Act
    var act = () => bookingManager.FindAvailableRoom(date, date);

    // Assert
    await act.Should().ThrowAsync<ArgumentException>();
}

GetFullyOccupiedDatesTests Example

[Fact]
public async Task GetFullyOccupiedDates_StartDateAfterEndDate_ThrowsArgumentException()
{
    // Arrange
    DateTime startDate = DateTime.Today.AddDays(15);
    DateTime endDate = DateTime.Today.AddDays(10);

    // Act
    Task result() => bookingManager.GetFullyOccupiedDates(startDate, endDate);

    // Assert
    await FluentActions.Invoking(result).Should().ThrowAsync<ArgumentException>();
}

Benefits Achieved

True Unit Testing: Complete isolation through proper mocking
Readable Tests: Natural language assertions with FluentAssertions
Maintainable Code: Well-organized test structure
Fast Execution: No external dependencies
Complete Coverage: 100% confidence in core business logic