Cot

You are a software tester writing JUnit 5 robustness tests in Java 17.
The system under test is a distributed microservice web application called TeaStore.
It is deployed via Docker Compose and exposed at http://localhost:8080.
All requests go through the WebUI service.

Available endpoints:

GET  /tools.descartes.teastore.webui/
GET  /tools.descartes.teastore.webui/category?id=<integer>
GET  /tools.descartes.teastore.webui/product?id=<integer>
GET  /tools.descartes.teastore.webui/cart
GET  /tools.descartes.teastore.webui/profile
POST /tools.descartes.teastore.webui/loginAction       body: username=<string>&password=<string>
POST /tools.descartes.teastore.webui/cartAction        body: addToCart=&productid=<integer>
POST /tools.descartes.teastore.webui/cartAction        body: removeProduct=&productid=<integer>
POST /tools.descartes.teastore.webui/order             body: confirm=

Robustness oracle:
The system passes a robustness test if the HTTP response status code is less than 500.
A 2xx, 3xx, or 4xx response means the system handled the input gracefully.
A 5xx response is a robustness failure.

Your test class must extend TeaStoreBaseTest which provides:
  HttpResponse<String> get(String path)
  HttpResponse<String> post(String path, String body)
  void assertNoServerError(HttpResponse<?> response)

Reasoning steps — work through these before writing any code:

Step 1 — Identify input categories per endpoint:
For each endpoint, list every parameter that can receive invalid input.
For each parameter, name the specific violation: empty, null-like, negative, out-of-range, wrong type, injection payload, oversized string.

Step 2 — Identify state-based scenarios:
Which endpoints require authentication or an active session?
What happens when those are called without a valid session?
What happens when cart actions are called without items in the cart?

Step 3 — Identify boundary conditions:
For integer id parameters: what are the boundary values? (negative, zero, max integer, non-integer string)
For string parameters: what are the boundary values? (empty, whitespace only, extremely long, special characters)

Step 4 — Identify system-level scenarios:
What happens if an unknown endpoint path is requested?
What happens if POST body is completely empty?
What happens if required parameters are missing entirely?

Step 5 — Select 15 to 18 tests:
From your analysis, select the most distinct violations across different endpoints.
Avoid duplicating the same violation on the same endpoint twice.

Step 6 — Write the Java class:
Translate your selected violations into JUnit 5 test methods.

Output format:

Package: com.example
Class name: TeaStore_ModelC_cot_RobustnessTest
Each test method must have a unique name starting with test_R1_
Each test must call get() or post() with a robustness input and then call assertNoServerError()
Do not use assertThrows
Import only from java.net.http and org.junit.jupiter.api
Output only the final Java class, no reasoning commentary in the output