feat: Add testplan_get_suites_by_test_case_id tool for reverse suite membership lookup

[alexneo2003]

Summary

Implement a new tool that integrates with Azure DevOps Test Plans API to enable reverse-lookup of test suite membership by test case ID — a critical missing capability for efficient test case management workflows.

Problem

Currently, determining which test suites contain a specific test case requires a forward-scan approach:

1. List all suites in a test plan (testplan_list_test_suites)
2. For each candidate suite, paginate through all test cases (testplan_list_test_cases with continuationToken)
3. Parse each response to check if the target test case ID is present

For plans with many suites and hundreds of test cases per suite, this results in 10–20+ API calls transferring large paginated payloads (~50KB+ per page), just to answer a simple question: "Which suites contain test case X?"

This is a common need for CI/CD pipelines that validate test case organization, automated test registration workflows, and test plan audit tools.

Solution

The Azure DevOps REST API already provides a dedicated reverse-lookup endpoint that returns all suites containing a given test case in a single lightweight call:

Tools

Develop the following tool with full parameter support, including optional ones:

testplan_get_suites_by_test_case_id: Get all test suites that contain a specific test case.

Endpoint: GET https://dev.azure.com/{organization}/_apis/testplan/suites?testCaseId={testCaseId}&api-version=7.2-preview.1

Parameters

Parameter	Type	Required	Description
testCaseId	number	✅	The ID of the test case to look up

Response

Returns an array of TestSuite objects, each containing:

• id — Suite ID
• name — Suite name
• plan — Parent test plan reference ({ id, name })
• parentSuite — Parent suite reference (if nested)
• suiteType — Type of suite (static, dynamic, requirement-based)

Reference: Suites - Get Suites By Test Case Id

Benefits

• ~90% reduction in API calls for suite membership checks (N test cases = N calls vs. N × M paginated suite scans)
• ~95% less data transferred — response is a compact array of suite references (~1KB) instead of full paginated test case lists (~50KB+ per page)
• Eliminates pagination complexity — no continuationToken handling needed for this use case
• Enables efficient CI/CD validation — pipeline steps can verify test case suite assignments in seconds instead of minutes
• Complements existing tools — fills the gap between testplan_list_test_suites (plan → suites) and testplan_list_test_cases (suite → cases) by adding the reverse direction (case → suites)

Rules

1. Adhere strictly to existing project standards and coding conventions.
2. Ensure the tool exposes all API parameters (required and optional).
3. Follow the same fetch()-based pattern used by testplan_list_test_plans and testplan_list_test_cases in src/tools/test-plans.ts.
4. Add the tool name to the Test_Plan_Tools constant object.
5. Include unit tests following the existing patterns in test/src/tools/test-plan.test.ts.

Special treat

If you follow the rules, you'll get candy! 🍬