test: add loadtest

Makefile

@@ -21,3 +21,6 @@ setup-development-environment: install-poetry $(PRE_COMMIT_HOOK)
 
 test-smoke:
 	k6 run tests/*.smoke.js
+
+test-loadtest:
+	k6 run tests/*.loadtest.js

tests/default.loadtest.js

@@ -0,0 +1,25 @@
+import http from 'k6/http';
+import { check, group, sleep } from 'k6';
+
+export const options = {
+  stages: [
+    { duration: '5s', target: 10 }, // simulate ramp-up of traffic from 1 to 10 users over 30s.
+    { duration: '30s', target: 10 }, // stay at 10 users for 10 minutes
+    { duration: '5s', target: 0 }, // ramp-down to 0 users
+  ],
+  thresholds: {
+    'http_req_duration': ['p(99)<1000'], // 99% of requests must complete below 1000ms
+  },
+};
+
+export default () => {
+  const payload = JSON.stringify({
+    prompt: "def binarySearch(arr, left, right, x):\n    mid = (left +",
+  });
+  const headers = { "Content-Type": "application/json" };
+  const res = http.post("http://localhost:5000/v1/completions", payload, {
+    headers,
+  });
+  check(res, { success: (r) => r.status === 200 });
+  sleep(0.5);
+};