test: divide cases according to parallelizibility

__tests__/non-parallel-cases/pjax.commits-page.ts

@@ -4,8 +4,6 @@ describe(`in Gitako project page`, () => {
   beforeAll(() => page.goto('https://github.com/EnixCoda/Gitako/commits/develop'))
 
   it('should not break go back in history', async () => {
-    // temporarily skip this test as GitHub has unexpected PJAX behaviors
-    return
     for (let i = 0; i < 3; i++) {
       const commitLinks = await page.$$(
         `#js-repo-pjax-container .TimelineItem-body ol li > div:nth-child(1) a[href*="/commit/"]`,

jest.config.js

@@ -61,7 +61,7 @@ module.exports = {
   // globals: {},
 
   // The maximum amount of workers used to run your tests. Can be specified as % or a number. E.g. maxWorkers: 10% will use 10% of your CPU amount + 1 as the maximum worker number. maxWorkers: 2 will use a maximum of 2 workers.
-  maxWorkers: 1, // more than 1 workers may make tabs in background and never renders Gitako's file items.
+  maxWorkers: 8,
 
   // An array of directory names to be searched recursively up from the requiring module's location
   // moduleDirectories: [

jest.non.parallel.config.js

@@ -0,0 +1,7 @@
+const baseConfig = require('./jest.config')
+
+module.exports = {
+  ...baseConfig,
+  maxWorkers: 1,
+  testMatch: ['**/__tests__/non-parallel-cases/*.ts?(x)'],
+}

package.json

@@ -14,7 +14,9 @@
     "postinstall": "rm -rf node_modules/@types/react-native && node scripts/fix-pjax-api",
     "build": "VERSION=v$(node scripts/get-version.js) NODE_ENV=production webpack",
     "roll": "make release",
-    "test": "NODE_ENV=test jest"
+    "test": "yarn run test:parallel && yarn run test:non-parallel",
+    "test:parallel": "NODE_ENV=test jest",
+    "test:non-parallel": "NODE_ENV=test jest --config jest.non.parallel.config.js"
   },
   "dependencies": {
     "@primer/components": "^22.0.2",