Add integration test to Core to verify system indices warning behavior

src/core/server/elasticsearch/integration_tests/client.test.ts

@@ -0,0 +1,57 @@
+/*
+ * 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 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+import {
+  createTestServers,
+  TestElasticsearchUtils,
+  TestKibanaUtils,
+} from '../../../test_helpers/kbn_server';
+
+describe('elasticsearch clients', () => {
+  let esServer: TestElasticsearchUtils;
+  let kibanaServer: TestKibanaUtils;
+
+  beforeAll(async () => {
+    const { startES, startKibana } = createTestServers({
+      adjustTimeout: jest.setTimeout,
+    });
+
+    esServer = await startES();
+    kibanaServer = await startKibana();
+  });
+
+  afterAll(async () => {
+    await kibanaServer.stop();
+    await esServer.stop();
+  });
+
+  it('does not return deprecation warning when x-elastic-product-origin header is set', async () => {
+    // Header should be automatically set by Core
+    const resp1 = await kibanaServer.coreStart.elasticsearch.client.asInternalUser.indices.getSettings(
+      { index: '.kibana' }
+    );
+    expect(resp1.headers).not.toHaveProperty('warning');
+
+    // Also test setting it explicitly
+    const resp2 = await kibanaServer.coreStart.elasticsearch.client.asInternalUser.indices.getSettings(
+      { index: '.kibana' },
+      { headers: { 'x-elastic-product-origin': 'kibana' } }
+    );
+    expect(resp2.headers).not.toHaveProperty('warning');
+  });
+
+  it('returns deprecation warning when x-elastic-product-orign header is not set', async () => {
+    const resp = await kibanaServer.coreStart.elasticsearch.client.asInternalUser.indices.getSettings(
+      { index: '.kibana' },
+      { headers: { 'x-elastic-product-origin': null } }
+    );
+
+    expect(resp.headers).toHaveProperty('warning');
+    expect(resp.headers!.warning).toMatch('system indices');
+  });
+});