2174 Locust Improve Coverage A0dbe353

Prompt: Achieve 100% Locust Coverage of All REST API Endpoints

Systematically extend tests/loadtest/locustfile.py to cover every REST API endpoint exposed by the platform. The goal is 100% endpoint coverage — every method+path in the OpenAPI spec has a corresponding @task in at least one Locust User class.

Prerequisite: All existing tests must pass with 0 failures first. See llms/prompts/locust-fix-failures.md.

Running Services

• Platform: localhost:8080 (nginx → gateway:4444, via docker-compose.yml)
• Locust UI: localhost:8089 (make load-test-ui)

Key Files

• tests/loadtest/locustfile.py — Main locust test file (~3660 lines, 30+ User classes)
• mcpgateway/routers/*.py — 19 router files defining all REST endpoints
• infra/nginx/nginx.conf — nginx reverse proxy (timeouts, routing)
• docker-compose.yml — service topology, env vars
• OpenAPI spec: GET http://localhost:8080/openapi.json

Step 1: Generate the Coverage Map

Extract every endpoint from the OpenAPI spec and cross-reference with existing locust tasks:

# Get all API endpoints (method + path)
curl -s http://localhost:8080/openapi.json | python3 -c "
import sys, json
spec = json.load(sys.stdin)
for path in sorted(spec.get('paths', {}).keys()):
    methods = [m.upper() for m in spec['paths'][path].keys() if m in ('get','post','put','delete','patch')]
    for m in methods:
        print(f'{m:7s} {path}')
"

# Get all endpoints currently tested in locustfile (grep for URL patterns)
grep -oP '(?:self\.client\.(get|post|put|delete|patch))\(\s*[f"]([^"]+)"' \
  tests/loadtest/locustfile.py | sort -u

Compare the two lists. Any endpoint in the OpenAPI spec but not in the locustfile is a coverage gap.

Step 2: Categorize Endpoints by Router Group

The API has 399 endpoints across these groups (by count):

Step 3: Manually Test New Endpoints Before Writing Locust Tasks

For every uncovered endpoint, manually test with curl first to understand the expected request/response:

# Generate admin JWT
export JWT=$(python3 -c "
import jwt, datetime, uuid
payload = {'sub':'admin@example.com',
  'exp':datetime.datetime.now(datetime.timezone.utc)+datetime.timedelta(hours=1),
  'iat':datetime.datetime.now(datetime.timezone.utc),
  'aud':'mcpgateway-api','iss':'mcpgateway',
  'jti':str(uuid.uuid4()),'teams':None,'is_admin':True}
print(jwt.encode(payload, 'my-test-key', algorithm='HS256'))")
AUTH="Authorization: Bearer $JWT"

# Example: test an uncovered endpoint
curl -s -w "\nHTTP %{http_code}\n" -H "$AUTH" http://localhost:8080/version
curl -s -w "\nHTTP %{http_code}\n" -H "$AUTH" http://localhost:8080/tags
curl -s -w "\nHTTP %{http_code}\n" -H "$AUTH" -X POST http://localhost:8080/logging/setLevel \
  -H "Content-Type: application/json" -d '{"level":"INFO"}'

# For admin HTMX endpoints, use Accept: text/html
curl -s -w "\nHTTP %{http_code}\n" -H "$AUTH" -H "Accept: text/html" http://localhost:8080/admin/plugins

Document the required headers, payload shape, and expected status codes for each endpoint before adding it to the locustfile.

Step 4: Add Missing Coverage Systematically

Follow the existing patterns in locustfile.py:

• One User class per logical group (e.g., LLMProviderUser, ServerWellKnownUser)
• Use @tag decorators for filtering (e.g., @tag("llm", "read"))
• Use catch_response=True with _validate_json_response() or _validate_html_response()
• Include realistic allowed_codes — don't just allow 200; include 401, 403, 404, 409, 422 where appropriate
• CRUD operations should create → read → update → delete in a single task method to avoid orphaned test data
• Weight classes appropriately — read-heavy users get higher weight, write/admin users get weight=1
• Clean up test data in on_stop() method

Endpoint categories to handle differently:

Step 5: Verify Coverage

After adding tasks, re-run the coverage map from Step 1 and confirm every endpoint has a corresponding task. Then:

# Light test to verify no failures
make load-test-light   # 10 users, 30s

# Check failures
curl -s http://localhost:8089/stats/requests/csv | awk -F',' '$4 > 0'

# Full test
make load-test-ui      # Start UI, configure desired load, run

Step 6: Create Coverage Tracking Document

Create todo/locust-coverage.md with:

1. Full endpoint list grouped by router
2. Coverage status for each (covered / not covered / skipped with reason)
3. Which User class covers each endpoint
4. Any endpoints intentionally skipped (SSE streaming, OAuth browser flows, etc.) with justification

Priority Order for Adding Coverage

1. Core REST API — /tools, /servers, /gateways, /resources, /prompts, /roots (CRUD + state + toggle)
2. Auth & RBAC — /auth/*, /rbac/*, /tokens/*, /teams/*
3. Observability — /api/logs/*, /api/metrics/*, /metrics/*
4. LLM & Chat — /llm/*, /llmchat/*, /v1/*
5. Admin UI pages — /admin/* (HTMX, lower priority but high endpoint count)
6. Specialized — /oauth/*, /reverse-proxy/*, /cancellation/*, /protocol/*
7. Singletons — /version, /tags, /export, /import, /sse, /.well-known/*