add: unit and integration testing

app/node_modules/jest/build/index.d.ts

@@ -0,0 +1,38 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {
+  SearchSource,
+  createTestScheduler,
+  getVersion,
+  runCLI,
+} from '@jest/core';
+import {Config as Config_2} from '@jest/types';
+import {buildArgv, run} from 'jest-cli';
+import {defineConfig, mergeConfig} from 'jest-config';
+
+export {buildArgv};
+
+export declare type Config = Config_2.InitialOptions;
+
+export {createTestScheduler};
+
+export {defineConfig};
+
+export {getVersion};
+
+export declare type GlobalConfig = Config_2.GlobalConfig;
+
+export {mergeConfig};
+
+export declare type ProjectConfig = Config_2.ProjectConfig;
+
+export {run};
+
+export {runCLI};
+
+export {SearchSource};