mock elastic-apm-node in @kbn/test jest preset (#120324)

* mock `elastic-apm-node` in `@kbn/test` jest preset

* adapt kbn-apm-config-loader tests

* use TS for agent mock

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

packages/kbn-apm-config-loader/src/init_apm.test.ts

@@ -12,13 +12,13 @@ import { initApm } from './init_apm';
 import apm from 'elastic-apm-node';
 
 describe('initApm', () => {
-  let apmAddFilterSpy: jest.SpyInstance;
-  let apmStartSpy: jest.SpyInstance;
+  let apmAddFilterMock: jest.Mock;
+  let apmStartMock: jest.Mock;
   let getConfig: jest.Mock;
 
   beforeEach(() => {
-    apmAddFilterSpy = jest.spyOn(apm, 'addFilter').mockImplementation(() => undefined);
-    apmStartSpy = jest.spyOn(apm, 'start').mockImplementation(() => undefined as any);
+    apmAddFilterMock = apm.addFilter as jest.Mock;
+    apmStartMock = apm.start as jest.Mock;
     getConfig = jest.fn();
 
     mockLoadConfiguration.mockImplementation(() => ({
@@ -27,7 +27,8 @@ describe('initApm', () => {
   });
 
   afterEach(() => {
-    jest.restoreAllMocks();
+    apmAddFilterMock.mockReset();
+    apmStartMock.mockReset();
     mockLoadConfiguration.mockReset();
   });
 
@@ -48,8 +49,8 @@ describe('initApm', () => {
   it('registers a filter using `addFilter`', () => {
     initApm(['foo', 'bar'], 'rootDir', true, 'service-name');
 
-    expect(apmAddFilterSpy).toHaveBeenCalledTimes(1);
-    expect(apmAddFilterSpy).toHaveBeenCalledWith(expect.any(Function));
+    expect(apmAddFilterMock).toHaveBeenCalledTimes(1);
+    expect(apmAddFilterMock).toHaveBeenCalledWith(expect.any(Function));
   });
 
   it('starts apm with the config returned from `getConfig`', () => {
@@ -60,7 +61,7 @@ describe('initApm', () => {
 
     initApm(['foo', 'bar'], 'rootDir', true, 'service-name');
 
-    expect(apmStartSpy).toHaveBeenCalledTimes(1);
-    expect(apmStartSpy).toHaveBeenCalledWith(config);
+    expect(apmStartMock).toHaveBeenCalledTimes(1);
+    expect(apmStartMock).toHaveBeenCalledWith(config);
   });
 });

packages/kbn-test/BUILD.bazel

@@ -76,6 +76,7 @@ TYPES_DEPS = [
   "//packages/kbn-i18n-react:npm_module_types",
   "//packages/kbn-utils",
   "@npm//@elastic/elasticsearch",
+  "@npm//elastic-apm-node",
   "@npm//del",
   "@npm//form-data",
   "@npm//jest",

packages/kbn-test/jest-preset.js

@@ -28,6 +28,7 @@ module.exports = {
   moduleNameMapper: {
     '@elastic/eui/lib/(.*)?': '<rootDir>/node_modules/@elastic/eui/test-env/$1',
     '@elastic/eui$': '<rootDir>/node_modules/@elastic/eui/test-env',
+    'elastic-apm-node': '<rootDir>/node_modules/@kbn/test/target_node/jest/mocks/apm_agent_mock.js',
     '\\.module.(css|scss)$':
       '<rootDir>/node_modules/@kbn/test/target_node/jest/mocks/css_module_mock.js',
     '\\.(css|less|scss)$': '<rootDir>/node_modules/@kbn/test/target_node/jest/mocks/style_mock.js',

packages/kbn-test/src/jest/mocks/apm_agent_mock.ts

@@ -0,0 +1,63 @@
+/*
+ * 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 type { Agent } from 'elastic-apm-node';
+
+/**
+ * `elastic-apm-node` patches the runtime at import time
+ *  causing memory leak with jest module sandbox, so it
+ *  needs to be mocked for tests
+ */
+const agent: jest.Mocked<Agent> = {
+  start: jest.fn().mockImplementation(() => agent),
+  isStarted: jest.fn().mockReturnValue(false),
+  getServiceName: jest.fn().mockReturnValue('mock-service'),
+  setFramework: jest.fn(),
+  addPatch: jest.fn(),
+  removePatch: jest.fn(),
+  clearPatches: jest.fn(),
+  lambda: jest.fn(),
+  handleUncaughtExceptions: jest.fn(),
+  captureError: jest.fn(),
+  currentTraceparent: null,
+  currentTraceIds: {},
+  startTransaction: jest.fn().mockReturnValue(null),
+  setTransactionName: jest.fn(),
+  endTransaction: jest.fn(),
+  currentTransaction: null,
+  startSpan: jest.fn(),
+  currentSpan: null,
+  setLabel: jest.fn().mockReturnValue(false),
+  addLabels: jest.fn().mockReturnValue(false),
+  setUserContext: jest.fn(),
+  setCustomContext: jest.fn(),
+  addFilter: jest.fn(),
+  addErrorFilter: jest.fn(),
+  addSpanFilter: jest.fn(),
+  addTransactionFilter: jest.fn(),
+  addMetadataFilter: jest.fn(),
+  flush: jest.fn(),
+  destroy: jest.fn(),
+  registerMetric: jest.fn(),
+  setTransactionOutcome: jest.fn(),
+  setSpanOutcome: jest.fn(),
+  middleware: {
+    connect: jest.fn().mockReturnValue(jest.fn()),
+  },
+  logger: {
+    fatal: jest.fn(),
+    error: jest.fn(),
+    warn: jest.fn(),
+    info: jest.fn(),
+    debug: jest.fn(),
+    trace: jest.fn(),
+  },
+};
+
+// eslint-disable-next-line import/no-default-export
+export default agent;