In Day2, I defined Test Infrastructure as the engineering foundation that makes software easier to test reliably and efficiently.
From today, I will start building one.
But first, I need a System Under Test (SUT).

And When I list my condition:
✓ Public and easy to access
✓ REST API
✓ CRUD operations
✓ Authentication
✓ Test data lifecycle
✓ Positive and negative scenarios
✓ Suitable for automation
✓ Simple enough for a 30-day project

After getting some references from AI, I found two SUTs that could be suitable for this project: Swagger Petstore vs. Restful Booker
For this project, I chose Restful Booker because its booking lifecycle and authentication flow give me enough scenarios to gradually build and improve my test infrastructure.

And waht should I test?
These would be the Possible Test Scope.

• Positive: Valid requests behave as expected
• Negative: Invalid requests or actions are handled appropriately
• Data Validation: Different input values and boundaries are validated
• State Validation: Data actually changes after operations
• Smoke: API is available and responding
• CRUD: Booking can be created, retrieved, updated, and deleted
• Authentication: Protected operations handle authentication correctly

After browsing the Restful Booker website, I defined a simple business flow:

Create Booking
↓
Get Booking
↓
Update Booking
↓
Verify Update
↓
Partial Update
↓
Delete Booking
↓
Verify Deletion

What I Will NOT Focus on First ?
✗ UI Testing
✗ Performance / Load Testing
✗ Penetration Testing
✗ Full Security Testing
✗ Browser Compatibility

I don't expect to implement everything at once. The goal of this project is to explore how test infrastructure evolves as the automation grows.