fix: act polyfill for React 15.x (#288)

Fixes #287

Author: Alex Zherdev

.all-contributorsrc

@@ -647,6 +647,16 @@
         "maintenance",
         "test"
       ]
+    },
+    {
+      "login": "alexzherdev",
+      "name": "Alex Zherdev",
+      "avatar_url": "https://avatars3.githubusercontent.com/u/93752?v=4",
+      "profile": "https://github.com/alexzherdev",
+      "contributions": [
+        "bug",
+        "code"
+      ]
     }
   ]
 }

README.md

@@ -26,7 +26,7 @@ practices.</p>
 [![version][version-badge]][package] [![downloads][downloads-badge]][npmtrends]
 [![MIT License][license-badge]][license]
 
-[![All Contributors](https://img.shields.io/badge/all_contributors-66-orange.svg?style=flat-square)](#contributors)
+[![All Contributors](https://img.shields.io/badge/all_contributors-67-orange.svg?style=flat-square)](#contributors)
 [![PRs Welcome][prs-badge]][prs] [![Code of Conduct][coc-badge]][coc]
 [![Join the community on Spectrum][spectrum-badge]][spectrum]
 
@@ -216,7 +216,7 @@ Thanks goes to these people ([emoji key][emojis]):
 | [<img src="https://avatars3.githubusercontent.com/u/881986?v=4" width="100px;" alt="dadamssg"/><br /><sub><b>dadamssg</b></sub>](https://github.com/dadamssg)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=dadamssg "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/8734097?v=4" width="100px;" alt="Yazan Aabed"/><br /><sub><b>Yazan Aabed</b></sub>](https://www.yaabed.com/)<br />[📝](#blog-YazanAabeed "Blogposts") | [<img src="https://avatars0.githubusercontent.com/u/556258?v=4" width="100px;" alt="Tim"/><br /><sub><b>Tim</b></sub>](https://github.com/timbonicus)<br />[🐛](https://github.com/kentcdodds/react-testing-library/issues?q=author%3Atimbonicus "Bug reports") [💻](https://github.com/kentcdodds/react-testing-library/commits?author=timbonicus "Code") [📖](https://github.com/kentcdodds/react-testing-library/commits?author=timbonicus "Documentation") [⚠️](https://github.com/kentcdodds/react-testing-library/commits?author=timbonicus "Tests") | [<img src="https://avatars3.githubusercontent.com/u/6682655?v=4" width="100px;" alt="Divyanshu Maithani"/><br /><sub><b>Divyanshu Maithani</b></sub>](http://divyanshu.xyz)<br />[✅](#tutorial-divyanshu013 "Tutorials") [📹](#video-divyanshu013 "Videos") | [<img src="https://avatars2.githubusercontent.com/u/9116042?v=4" width="100px;" alt="Deepak Grover"/><br /><sub><b>Deepak Grover</b></sub>](https://www.linkedin.com/in/metagrover)<br />[✅](#tutorial-metagrover "Tutorials") [📹](#video-metagrover "Videos") | [<img src="https://avatars0.githubusercontent.com/u/16276358?v=4" width="100px;" alt="Eyal Cohen"/><br /><sub><b>Eyal Cohen</b></sub>](https://github.com/eyalcohen4)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=eyalcohen4 "Documentation") | [<img src="https://avatars3.githubusercontent.com/u/7452681?v=4" width="100px;" alt="Peter Makowski"/><br /><sub><b>Peter Makowski</b></sub>](https://github.com/petermakowski)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=petermakowski "Documentation") |
 | [<img src="https://avatars2.githubusercontent.com/u/20361668?v=4" width="100px;" alt="Michiel Nuyts"/><br /><sub><b>Michiel Nuyts</b></sub>](https://github.com/Michielnuyts)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=Michielnuyts "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/1195863?v=4" width="100px;" alt="Joe Ng'ethe"/><br /><sub><b>Joe Ng'ethe</b></sub>](https://github.com/joeynimu)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=joeynimu "Code") [📖](https://github.com/kentcdodds/react-testing-library/commits?author=joeynimu "Documentation") | [<img src="https://avatars3.githubusercontent.com/u/19998290?v=4" width="100px;" alt="Kate"/><br /><sub><b>Kate</b></sub>](https://github.com/Enikol)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=Enikol "Documentation") | [<img src="https://avatars1.githubusercontent.com/u/11980217?v=4" width="100px;" alt="Sean"/><br /><sub><b>Sean</b></sub>](http://www.seanrparker.com)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=SeanRParker "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/17031?v=4" width="100px;" alt="James Long"/><br /><sub><b>James Long</b></sub>](http://jlongster.com)<br />[🤔](#ideas-jlongster "Ideas, Planning, & Feedback") [📦](#platform-jlongster "Packaging/porting to new platform") | [<img src="https://avatars1.githubusercontent.com/u/10118777?v=4" width="100px;" alt="Herb Hagely"/><br /><sub><b>Herb Hagely</b></sub>](https://github.com/hhagely)<br />[💡](#example-hhagely "Examples") | [<img src="https://avatars2.githubusercontent.com/u/5779538?v=4" width="100px;" alt="Alex Wendte"/><br /><sub><b>Alex Wendte</b></sub>](http://www.wendtedesigns.com/)<br />[💡](#example-themostcolm "Examples") |
 | [<img src="https://avatars0.githubusercontent.com/u/6998954?v=4" width="100px;" alt="Monica Powell"/><br /><sub><b>Monica Powell</b></sub>](http://www.aboutmonica.com)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=M0nica "Documentation") | [<img src="https://avatars1.githubusercontent.com/u/2699953?v=4" width="100px;" alt="Vitaly Sivkov"/><br /><sub><b>Vitaly Sivkov</b></sub>](http://sivkoff.com)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=sivkoff "Code") | [<img src="https://avatars3.githubusercontent.com/u/7049?v=4" width="100px;" alt="Weyert de Boer"/><br /><sub><b>Weyert de Boer</b></sub>](https://github.com/weyert)<br />[🤔](#ideas-weyert "Ideas, Planning, & Feedback") [👀](#review-weyert "Reviewed Pull Requests") | [<img src="https://avatars3.githubusercontent.com/u/13613037?v=4" width="100px;" alt="EstebanMarin"/><br /><sub><b>EstebanMarin</b></sub>](https://github.com/EstebanMarin)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=EstebanMarin "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/13953703?v=4" width="100px;" alt="Victor Martins"/><br /><sub><b>Victor Martins</b></sub>](https://github.com/vctormb)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=vctormb "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/19773?v=4" width="100px;" alt="Royston Shufflebotham"/><br /><sub><b>Royston Shufflebotham</b></sub>](https://github.com/RoystonS)<br />[🐛](https://github.com/kentcdodds/react-testing-library/issues?q=author%3ARoystonS "Bug reports") [📖](https://github.com/kentcdodds/react-testing-library/commits?author=RoystonS "Documentation") [💡](#example-RoystonS "Examples") | [<img src="https://avatars0.githubusercontent.com/u/6834804?v=4" width="100px;" alt="chrbala"/><br /><sub><b>chrbala</b></sub>](https://github.com/chrbala)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=chrbala "Code") |
-| [<img src="https://avatars3.githubusercontent.com/u/887639?v=4" width="100px;" alt="Donavon West"/><br /><sub><b>Donavon West</b></sub>](http://donavon.com)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=donavon "Code") [📖](https://github.com/kentcdodds/react-testing-library/commits?author=donavon "Documentation") [🤔](#ideas-donavon "Ideas, Planning, & Feedback") [⚠️](https://github.com/kentcdodds/react-testing-library/commits?author=donavon "Tests") | [<img src="https://avatars2.githubusercontent.com/u/689081?v=4" width="100px;" alt="Richard Maisano"/><br /><sub><b>Richard Maisano</b></sub>](https://github.com/maisano)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=maisano "Code") | [<img src="https://avatars0.githubusercontent.com/u/5244986?v=4" width="100px;" alt="Marco Biedermann"/><br /><sub><b>Marco Biedermann</b></sub>](https://www.marcobiedermann.com)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=marcobiedermann "Code") [🚧](#maintenance-marcobiedermann "Maintenance") [⚠️](https://github.com/kentcdodds/react-testing-library/commits?author=marcobiedermann "Tests") |
+| [<img src="https://avatars3.githubusercontent.com/u/887639?v=4" width="100px;" alt="Donavon West"/><br /><sub><b>Donavon West</b></sub>](http://donavon.com)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=donavon "Code") [📖](https://github.com/kentcdodds/react-testing-library/commits?author=donavon "Documentation") [🤔](#ideas-donavon "Ideas, Planning, & Feedback") [⚠️](https://github.com/kentcdodds/react-testing-library/commits?author=donavon "Tests") | [<img src="https://avatars2.githubusercontent.com/u/689081?v=4" width="100px;" alt="Richard Maisano"/><br /><sub><b>Richard Maisano</b></sub>](https://github.com/maisano)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=maisano "Code") | [<img src="https://avatars0.githubusercontent.com/u/5244986?v=4" width="100px;" alt="Marco Biedermann"/><br /><sub><b>Marco Biedermann</b></sub>](https://www.marcobiedermann.com)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=marcobiedermann "Code") [🚧](#maintenance-marcobiedermann "Maintenance") [⚠️](https://github.com/kentcdodds/react-testing-library/commits?author=marcobiedermann "Tests") | [<img src="https://avatars3.githubusercontent.com/u/93752?v=4" width="100px;" alt="Alex Zherdev"/><br /><sub><b>Alex Zherdev</b></sub>](https://github.com/alexzherdev)<br />[🐛](https://github.com/kentcdodds/react-testing-library/issues?q=author%3Aalexzherdev "Bug reports") [💻](https://github.com/kentcdodds/react-testing-library/commits?author=alexzherdev "Code") |
 
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 

src/act-compat.js

@@ -1,3 +1,4 @@
+import React from 'react'
 import ReactDOM from 'react-dom'
 import {act as reactAct} from 'react-dom/test-utils'
 
@@ -7,7 +8,7 @@ import {act as reactAct} from 'react-dom/test-utils'
 // better than nothing.
 function actPolyfill(cb) {
   ReactDOM.unstable_batchedUpdates(cb)
-  ReactDOM.render(null, document.createElement('div'))
+  ReactDOM.render(<div />, document.createElement('div'))
 }
 
 const act = reactAct || actPolyfill