[EPMTIOOPS-20537] Document Test Cases list, update, and delete endpoints

Documents the new GET (list), PUT, and DELETE endpoints added in
test-IO/app#12435, plus the previously-undocumented GET (single) endpoint
that already existed in the API.

Author: aliaksandr5filippov

src/pages/docs/api/test-cases.md

@@ -1,9 +1,60 @@
 ---
 title: Test Cases
-description: Create test cases
+description: Create, list, update, and delete test cases
 ---
 
-Create test cases for your products.
+Create and manage test cases for your products.
+
+## Get test case
+
+Retrieve a specific test case by ID.
+
+**Endpoint:** `GET /products/{product_id}/test_cases/{test_case_id}`
+
+**Parameters:**
+
+- `product_id` (number, required) - ID of the Product
+- `test_case_id` (number, required) - ID of the Test Case
+
+**Example Request:**
+
+{% code language="bash" showLineNumbers=true %}
+
+```bash
+curl -X GET "https://api.test.io/customer/v2/products/1/test_cases/123" \
+  -H "Authorization: Token YOUR_API_TOKEN"
+```
+
+{% /code %}
+
+**Response:** `200 OK`
+
+Returns the test case object. See the response shape in [Create a bulk of test cases](#create-a-bulk-of-test-cases) below.
+
+## List test cases
+
+Returns all visible (non-hidden) test cases for a product.
+
+**Endpoint:** `GET /products/{product_id}/test_cases`
+
+**Parameters:**
+
+- `product_id` (number, required) - ID of the Product
+
+**Example Request:**
+
+{% code language="bash" showLineNumbers=true %}
+
+```bash
+curl -X GET "https://api.test.io/customer/v2/products/1/test_cases" \
+  -H "Authorization: Token YOUR_API_TOKEN"
+```
+
+{% /code %}
+
+**Response:** `200 OK`
+
+Returns an array of test case objects. See the response shape in [Create a bulk of test cases](#create-a-bulk-of-test-cases) below.
 
 ## Create a bulk of test cases
 
@@ -69,3 +120,72 @@ Returns an array of created test case objects.
 {% callout type="note" %}
 In the response, the steps field is returned as `steps` (not `test_case_steps` as in the request). Each step object in the response also includes `id`, `test_case_id`, and `target_idx` fields.
 {% /callout %}
+
+## Update test case
+
+Updates the top-level fields of a test case. Test case steps are not managed through this endpoint.
+
+**Endpoint:** `PUT /products/{product_id}/test_cases/{test_case_id}`
+
+**Parameters:**
+
+- `product_id` (number, required) - ID of the Product
+- `test_case_id` (number, required) - ID of the Test Case
+
+All attributes must be provided inside the root object `test_case`. All fields are optional — only the fields you provide are updated.
+
+**Request Body:**
+
+- `title` (string, optional) - Title of the test case
+- `requirements` (string, optional) - Requirements of the test case
+- `target_idx` (string, optional) - Reference of the test case in other system
+- `feature_id` (number, optional) - ID of the Feature to move the test case to. Must belong to the same product.
+
+**Example Request:**
+
+{% code language="bash" showLineNumbers=true %}
+
+```bash
+curl -X PUT "https://api.test.io/customer/v2/products/1/test_cases/123" \
+  -H "Authorization: Token YOUR_API_TOKEN" \
+  -H "Content-Type: application/json" \
+  -d '{
+    "test_case": {
+      "title": "Login Test (updated)"
+    }
+  }'
+```
+
+{% /code %}
+
+**Response:** `200 OK`
+
+Returns the updated test case object. See the response shape in [Create a bulk of test cases](#create-a-bulk-of-test-cases) above.
+
+## Delete test case
+
+Deletes the specified test case from the product.
+
+**Endpoint:** `DELETE /products/{product_id}/test_cases/{test_case_id}`
+
+**Parameters:**
+
+- `product_id` (number, required) - ID of the Product
+- `test_case_id` (number, required) - ID of the Test Case
+
+{% callout type="note" %}
+If the test case is already in use by a test cycle, it is not permanently deleted — it is hidden instead so historical test results remain intact. Hidden test cases no longer appear in [List test cases](#list-test-cases).
+{% /callout %}
+
+**Example Request:**
+
+{% code language="bash" showLineNumbers=true %}
+
+```bash
+curl -X DELETE "https://api.test.io/customer/v2/products/1/test_cases/123" \
+  -H "Authorization: Token YOUR_API_TOKEN"
+```
+
+{% /code %}
+
+**Response:** `204 No Content`