add ssr test

Author: li-jia-nan

tests/ssr.test.tsx

@@ -0,0 +1,14 @@
+import React from 'react';
+import { renderToString } from 'react-dom/server';
+import MutateObserver from '../src';
+
+describe('SSR', () => {
+  const fn = jest.fn();
+  it('No Render in SSR', () => {
+    renderToString(
+      <MutateObserver onMutate={fn}>
+        <button>test</button>
+      </MutateObserver>,
+    );
+  });
+});