test: update the test for sync mutation

test/use-swr-local-mutation.test.tsx

@@ -1,5 +1,6 @@
 import { act, render, screen, fireEvent } from '@testing-library/react'
 import React, { useEffect, useState } from 'react'
+import { unstable_batchedUpdates } from 'react-dom'
 import useSWR, { mutate, cache } from '../src'
 import { sleep } from './utils'
 
@@ -502,7 +503,7 @@ describe('useSWR - local mutation', () => {
     }
   })
 
-  it('should dedupe synchronous mutations', async () => {
+  it('should apply synchronous mutations independently', async () => {
     const mutationRecivedValues = []
     const renderRecivedValues = []
 
@@ -511,15 +512,19 @@ describe('useSWR - local mutation', () => {
 
       useEffect(() => {
         setTimeout(() => {
-          // let's mutate twice, synchronously
-          boundMutate(v => {
-            mutationRecivedValues.push(v) // should be 0
-            return 1
-          }, false)
-          boundMutate(v => {
-            mutationRecivedValues.push(v) // should be 1
-            return 2
-          }, false)
+          // swr no longer batch sync mutations
+          // so you have to batch the updates on yourself
+          unstable_batchedUpdates(() => {
+            // let's mutate twice, synchronously
+            boundMutate(v => {
+              mutationRecivedValues.push(v) // should be 0
+              return 1
+            }, false)
+            boundMutate(v => {
+              mutationRecivedValues.push(v) // should be 1
+              return 2
+            }, false)
+          })
         }, 1)
         // the mutate function is guaranteed to be the same reference
         // eslint-disable-next-line react-hooks/exhaustive-deps