Confirm preAuth handler only added when max > 0

x-pack/plugins/ingest_manager/server/routes/limited_concurrency.test.ts

@@ -0,0 +1,35 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { coreMock } from 'src/core/server/mocks';
+import { registerLimitedConcurrencyRoutes } from './limited_concurrency';
+import { IngestManagerConfigType } from '../index';
+
+describe('registerLimitedConcurrencyRoutes', () => {
+  test(`doesn't call registerOnPreAuth if maxConcurrentConnections is 0`, async () => {
+    const mockSetup = coreMock.createSetup();
+    const mockConfig = { fleet: { maxConcurrentConnections: 0 } } as IngestManagerConfigType;
+    registerLimitedConcurrencyRoutes(mockSetup, mockConfig);
+
+    expect(mockSetup.http.registerOnPreAuth).not.toHaveBeenCalled();
+  });
+
+  test(`calls registerOnPreAuth once if maxConcurrentConnections is 1`, async () => {
+    const mockSetup = coreMock.createSetup();
+    const mockConfig = { fleet: { maxConcurrentConnections: 1 } } as IngestManagerConfigType;
+    registerLimitedConcurrencyRoutes(mockSetup, mockConfig);
+
+    expect(mockSetup.http.registerOnPreAuth).toHaveBeenCalledTimes(1);
+  });
+
+  test(`calls registerOnPreAuth once if maxConcurrentConnections is 1000`, async () => {
+    const mockSetup = coreMock.createSetup();
+    const mockConfig = { fleet: { maxConcurrentConnections: 1000 } } as IngestManagerConfigType;
+    registerLimitedConcurrencyRoutes(mockSetup, mockConfig);
+
+    expect(mockSetup.http.registerOnPreAuth).toHaveBeenCalledTimes(1);
+  });
+});