added waitForExpect

.all-contributorsrc

@@ -85,6 +85,16 @@
       "contributions": [
         "doc"
       ]
+    },
+    {
+      "login": "lgandecki",
+      "name": "Łukasz Gandecki",
+      "avatar_url": "https://avatars1.githubusercontent.com/u/4002543?v=4",
+      "profile": "http://team.thebrain.pro",
+      "contributions": [
+        "code",
+        "test"
+      ]
     }
   ]
 }

README.md

@@ -16,7 +16,7 @@
 [![downloads][downloads-badge]][npmtrends]
 [![MIT License][license-badge]][license]
 
-[![All Contributors](https://img.shields.io/badge/all_contributors-8-orange.svg?style=flat-square)](#contributors)
+[![All Contributors](https://img.shields.io/badge/all_contributors-9-orange.svg?style=flat-square)](#contributors)
 [![PRs Welcome][prs-badge]][prs]
 [![Code of Conduct][coc-badge]][coc]
 
@@ -564,7 +564,7 @@ Thanks goes to these people ([emoji key][emojis]):
 <!-- prettier-ignore -->
 | [<img src="https://avatars.githubusercontent.com/u/1500684?v=3" width="100px;"/><br /><sub><b>Kent C. Dodds</b></sub>](https://kentcdodds.com)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=kentcdodds "Code") [📖](https://github.com/kentcdodds/react-testing-library/commits?author=kentcdodds "Documentation") [🚇](#infra-kentcdodds "Infrastructure (Hosting, Build-Tools, etc)") [⚠️](https://github.com/kentcdodds/react-testing-library/commits?author=kentcdodds "Tests") | [<img src="https://avatars1.githubusercontent.com/u/2430381?v=4" width="100px;"/><br /><sub><b>Ryan Castner</b></sub>](http://audiolion.github.io)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=audiolion "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/8008023?v=4" width="100px;"/><br /><sub><b>Daniel Sandiego</b></sub>](https://www.dnlsandiego.com)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=dnlsandiego "Code") | [<img src="https://avatars2.githubusercontent.com/u/12592677?v=4" width="100px;"/><br /><sub><b>Paweł Mikołajczyk</b></sub>](https://github.com/Miklet)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=Miklet "Code") | [<img src="https://avatars3.githubusercontent.com/u/464978?v=4" width="100px;"/><br /><sub><b>Alejandro Ñáñez Ortiz</b></sub>](http://co.linkedin.com/in/alejandronanez/)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=alejandronanez "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/1402095?v=4" width="100px;"/><br /><sub><b>Matt Parrish</b></sub>](https://github.com/pbomb)<br />[🐛](https://github.com/kentcdodds/react-testing-library/issues?q=author%3Apbomb "Bug reports") [💻](https://github.com/kentcdodds/react-testing-library/commits?author=pbomb "Code") [📖](https://github.com/kentcdodds/react-testing-library/commits?author=pbomb "Documentation") [⚠️](https://github.com/kentcdodds/react-testing-library/commits?author=pbomb "Tests") | [<img src="https://avatars1.githubusercontent.com/u/1288694?v=4" width="100px;"/><br /><sub><b>Justin Hall</b></sub>](https://github.com/wKovacs64)<br />[📦](#platform-wKovacs64 "Packaging/porting to new platform") |
 | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
-| [<img src="https://avatars2.githubusercontent.com/u/3462296?v=4" width="100px;"/><br /><sub><b>Jonah Moses</b></sub>](https://github.com/JonahMoses)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=JonahMoses "Documentation") |
+| [<img src="https://avatars2.githubusercontent.com/u/3462296?v=4" width="100px;"/><br /><sub><b>Jonah Moses</b></sub>](https://github.com/JonahMoses)<br />[📖](https://github.com/kentcdodds/react-testing-library/commits?author=JonahMoses "Documentation") | [<img src="https://avatars1.githubusercontent.com/u/4002543?v=4" width="100px;"/><br /><sub><b>Łukasz Gandecki</b></sub>](http://team.thebrain.pro)<br />[💻](https://github.com/kentcdodds/react-testing-library/commits?author=lgandecki "Code") [⚠️](https://github.com/kentcdodds/react-testing-library/commits?author=lgandecki "Tests") |
 
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 

package.json

@@ -24,7 +24,9 @@
   "keywords": [],
   "author": "Kent C. Dodds <[email protected]> (http://kentcdodds.com/)",
   "license": "MIT",
-  "dependencies": {},
+  "dependencies": {
+    "wait-for-expect": "^0.1.0"
+  },
   "devDependencies": {
     "@types/react-dom": "^16.0.4",
     "axios": "^0.18.0",

src/__tests__/end-to-end.js

@@ -0,0 +1,42 @@
+import React from 'react'
+import {render, waitForExpect} from '../'
+
+const fetchAMessage = () =>
+  new Promise(resolve => {
+    // we are using random timeout here to simulate a real-time example
+    // of an async operation calling a callback at a non-deterministic time
+    const randomTimeout = Math.floor(Math.random() * 100)
+    setTimeout(() => {
+      resolve({returnedMessage: 'Hello World'})
+    }, randomTimeout)
+  })
+
+class ComponentWithLoader extends React.Component {
+  state = {loading: true}
+  async componentDidMount() {
+    const data = await fetchAMessage()
+    this.setState({data, loading: false}) // eslint-disable-line
+  }
+  render() {
+    if (this.state.loading) {
+      return <div>Loading...</div>
+    } else {
+      return (
+        <div data-testid="message">
+          Loaded this message: {this.state.data.returnedMessage}!
+        </div>
+      )
+    }
+  }
+}
+
+test('it waits for the data to be loaded', async () => {
+  const {queryByText, queryByTestId} = render(<ComponentWithLoader />)
+
+  expect(queryByText('Loading...')).toBeTruthy()
+
+  await waitForExpect(() => {
+    expect(queryByText('Loading...')).toBeNull()
+    expect(queryByTestId('message').textContent).toMatch(/Hello World/)
+  })
+})

src/index.js

@@ -1,5 +1,6 @@
 import ReactDOM from 'react-dom'
 import {Simulate} from 'react-dom/test-utils'
+import waitForExpect from 'wait-for-expect'
 import * as queries from './queries'
 
 function render(ui, {container = document.createElement('div')} = {}) {
@@ -24,4 +25,4 @@ function flushPromises() {
   return new Promise(resolve => setImmediate(resolve))
 }
 
-export {render, flushPromises, Simulate}
+export {render, flushPromises, Simulate, waitForExpect}