Add benchmark tests and its runner.

Author: rickypc

__benches__/index.test.js

@@ -0,0 +1,38 @@
+/* index.test.js - Benchmark tests for React store context hooks functionality.
+ * Copyright (c) 2019 - 2021 Richard Huang <rickypc@users.noreply.github.com>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+import proxyquire from 'proxyquire';
+import run from './runner.js';
+
+const Component = () => null;
+const context = {
+  get() {},
+  remove() {},
+  set() {},
+  sets() {},
+};
+
+const {
+  isEmpty,
+  useStore,
+  useStores,
+  withStore,
+} = proxyquire('../src/index.js', {
+  react: {
+    createContext: () => context,
+    useCallback: (cb) => cb,
+    useContext: () => context,
+    useState() {},
+  },
+});
+
+(async () => {
+  await run('isEmpty', () => isEmpty(false));
+  await run('useStore', () => useStore('key', 'default'));
+  await run('useStores', () => useStores({ key1: 'value1' }));
+  await run('withStore', () => withStore(Component));
+})();

__benches__/runner.js

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+/* runner.js - Benchmark test runner for React store context hooks.
+ * Copyright (c) 2019 - 2021 Richard Huang <rickypc@users.noreply.github.com>
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+import Benchmark from 'benchmark';
+
+Benchmark.options.maxTime = 0;
+Benchmark.options.minSamples = 5;
+
+export default (name, fn) => new Promise((resolve) => ((new Benchmark(name,
+  { defer: true, fn: async (d) => d.resolve(await fn()) }))
+  .on('complete', (evt) => {
+    process.stdout.write(`${evt.target}\n`);
+    resolve();
+  })
+  .on('error', (evt) => {
+    throw evt.target.error;
+  })
+  .run({ async: true })));