[Obs AI Assistant] Add alerts test to serverless (#205524) (#205530)

Closes https://github.com/elastic/kibana/issues/205524

## Summary

Adds the alerts.spec to serverless tests. It's skipped in MKI because of
the LLM proxy. There is an open issue for this -
https://github.com/elastic/kibana/issues/192751

### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [x] The PR description includes the appropriate Release Notes section,
and the correct `release_note:*` label is applied per the
[guidelines](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

x-pack/test_serverless/api_integration/test_suites/observability/ai_assistant/tests/complete/functions/alerts.spec.ts

@@ -0,0 +1,93 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+import { MessageAddEvent, MessageRole } from '@kbn/observability-ai-assistant-plugin/common';
+import expect from '@kbn/expect';
+import {
+  LlmProxy,
+  createLlmProxy,
+} from '@kbn/test-suites-xpack/observability_ai_assistant_api_integration/common/create_llm_proxy';
+import { FtrProviderContext } from '../../../common/ftr_provider_context';
+import { getMessageAddedEvents, invokeChatCompleteWithFunctionRequest } from './helpers';
+import {
+  createProxyActionConnector,
+  deleteActionConnector,
+} from '../../../common/action_connectors';
+import type { InternalRequestHeader, RoleCredentials } from '../../../../../../../shared/services';
+
+export default function ApiTest({ getService }: FtrProviderContext) {
+  const supertest = getService('supertest');
+  const log = getService('log');
+  const svlUserManager = getService('svlUserManager');
+  const svlCommonApi = getService('svlCommonApi');
+  const observabilityAIAssistantAPIClient = getService('observabilityAIAssistantAPIClient');
+
+  describe('when calling the alerts function', function () {
+    // TODO: https://github.com/elastic/kibana/issues/192751
+    this.tags(['skipMKI']);
+    let roleAuthc: RoleCredentials;
+    let internalReqHeader: InternalRequestHeader;
+    let proxy: LlmProxy;
+    let connectorId: string;
+    let alertsEvents: MessageAddEvent[];
+
+    const start = 'now-100h';
+    const end = 'now';
+
+    before(async () => {
+      roleAuthc = await svlUserManager.createM2mApiKeyWithRoleScope('editor');
+      internalReqHeader = svlCommonApi.getInternalRequestHeader();
+      proxy = await createLlmProxy(log);
+      connectorId = await createProxyActionConnector({
+        supertest,
+        log,
+        port: proxy.getPort(),
+        roleAuthc,
+        internalReqHeader,
+      });
+
+      void proxy
+        .intercept('conversation', () => true, 'Hello from LLM Proxy')
+        .completeAfterIntercept();
+
+      const alertsResponseBody = await invokeChatCompleteWithFunctionRequest({
+        connectorId,
+        observabilityAIAssistantAPIClient,
+        functionCall: {
+          name: 'alerts',
+          trigger: MessageRole.Assistant,
+          arguments: JSON.stringify({ start, end }),
+        },
+      });
+
+      await proxy.waitForAllInterceptorsSettled();
+
+      alertsEvents = getMessageAddedEvents(alertsResponseBody);
+    });
+
+    after(async () => {
+      proxy.close();
+      await deleteActionConnector({ supertest, connectorId, log, roleAuthc, internalReqHeader });
+      await svlUserManager.invalidateM2mApiKeyWithRoleScope(roleAuthc);
+    });
+
+    // This test ensures that invoking the alerts function does not result in an error.
+    it('should execute the function without any errors', async () => {
+      const alertsFunctionResponse = alertsEvents[0];
+      expect(alertsFunctionResponse.message.message.name).to.be('alerts');
+
+      const parsedAlertsResponse = JSON.parse(alertsFunctionResponse.message.message.content!);
+
+      expect(parsedAlertsResponse).not.to.have.property('error');
+      expect(parsedAlertsResponse).to.have.property('total');
+      expect(parsedAlertsResponse).to.have.property('alerts');
+      expect(parsedAlertsResponse.alerts).to.be.an('array');
+      expect(parsedAlertsResponse.total).to.be(0);
+      expect(parsedAlertsResponse.alerts.length).to.be(0);
+    });
+  });
+}