fix: toBeInTheDocument unclear error message on null element (#79)

.all-contributorsrc

@@ -209,6 +209,16 @@
       "contributions": [
         "bug"
       ]
+    },
+    {
+      "login": "dreyks",
+      "name": "Roman Usherenko",
+      "avatar_url": "https://avatars3.githubusercontent.com/u/1481264?v=4",
+      "profile": "https://github.com/dreyks",
+      "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-20-orange.svg?style=flat-square)](#contributors)
+[![All Contributors](https://img.shields.io/badge/all_contributors-21-orange.svg?style=flat-square)](#contributors)
 [![PRs Welcome][prs-badge]][prs]
 [![Code of Conduct][coc-badge]][coc]
 
@@ -746,10 +746,10 @@ Thanks goes to these people ([emoji key][emojis]):
 
 <!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
 <!-- 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/gnapse/jest-dom/commits?author=kentcdodds "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=kentcdodds "Documentation") [🚇](#infra-kentcdodds "Infrastructure (Hosting, Build-Tools, etc)") [⚠️](https://github.com/gnapse/jest-dom/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/gnapse/jest-dom/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/gnapse/jest-dom/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/gnapse/jest-dom/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/gnapse/jest-dom/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/gnapse/jest-dom/issues?q=author%3Apbomb "Bug reports") [💻](https://github.com/gnapse/jest-dom/commits?author=pbomb "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=pbomb "Documentation") [⚠️](https://github.com/gnapse/jest-dom/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://avatars.githubusercontent.com/u/1500684?v=3" width="100px;" alt="Kent C. Dodds"/><br /><sub><b>Kent C. Dodds</b></sub>](https://kentcdodds.com)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=kentcdodds "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=kentcdodds "Documentation") [🚇](#infra-kentcdodds "Infrastructure (Hosting, Build-Tools, etc)") [⚠️](https://github.com/gnapse/jest-dom/commits?author=kentcdodds "Tests") | [<img src="https://avatars1.githubusercontent.com/u/2430381?v=4" width="100px;" alt="Ryan Castner"/><br /><sub><b>Ryan Castner</b></sub>](http://audiolion.github.io)<br />[📖](https://github.com/gnapse/jest-dom/commits?author=audiolion "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/8008023?v=4" width="100px;" alt="Daniel Sandiego"/><br /><sub><b>Daniel Sandiego</b></sub>](https://www.dnlsandiego.com)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=dnlsandiego "Code") | [<img src="https://avatars2.githubusercontent.com/u/12592677?v=4" width="100px;" alt="Paweł Mikołajczyk"/><br /><sub><b>Paweł Mikołajczyk</b></sub>](https://github.com/Miklet)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=Miklet "Code") | [<img src="https://avatars3.githubusercontent.com/u/464978?v=4" width="100px;" alt="Alejandro Ñáñez Ortiz"/><br /><sub><b>Alejandro Ñáñez Ortiz</b></sub>](http://co.linkedin.com/in/alejandronanez/)<br />[📖](https://github.com/gnapse/jest-dom/commits?author=alejandronanez "Documentation") | [<img src="https://avatars0.githubusercontent.com/u/1402095?v=4" width="100px;" alt="Matt Parrish"/><br /><sub><b>Matt Parrish</b></sub>](https://github.com/pbomb)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Apbomb "Bug reports") [💻](https://github.com/gnapse/jest-dom/commits?author=pbomb "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=pbomb "Documentation") [⚠️](https://github.com/gnapse/jest-dom/commits?author=pbomb "Tests") | [<img src="https://avatars1.githubusercontent.com/u/1288694?v=4" width="100px;" alt="Justin Hall"/><br /><sub><b>Justin Hall</b></sub>](https://github.com/wKovacs64)<br />[📦](#platform-wKovacs64 "Packaging/porting to new platform") |
 | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
-| [<img src="https://avatars1.githubusercontent.com/u/1241511?s=460&v=4" width="100px;"/><br /><sub><b>Anto Aravinth</b></sub>](https://github.com/antoaravinth)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=antoaravinth "Code") [⚠️](https://github.com/gnapse/jest-dom/commits?author=antoaravinth "Tests") [📖](https://github.com/gnapse/jest-dom/commits?author=antoaravinth "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/gnapse/jest-dom/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/gnapse/jest-dom/commits?author=lgandecki "Code") [⚠️](https://github.com/gnapse/jest-dom/commits?author=lgandecki "Tests") [📖](https://github.com/gnapse/jest-dom/commits?author=lgandecki "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/498274?v=4" width="100px;"/><br /><sub><b>Ivan Babak</b></sub>](https://sompylasar.github.io)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Asompylasar "Bug reports") [🤔](#ideas-sompylasar "Ideas, Planning, & Feedback") | [<img src="https://avatars3.githubusercontent.com/u/4439618?v=4" width="100px;"/><br /><sub><b>Jesse Day</b></sub>](https://github.com/jday3)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=jday3 "Code") | [<img src="https://avatars0.githubusercontent.com/u/15199?v=4" width="100px;"/><br /><sub><b>Ernesto García</b></sub>](http://gnapse.github.io)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=gnapse "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=gnapse "Documentation") [⚠️](https://github.com/gnapse/jest-dom/commits?author=gnapse "Tests") | [<img src="https://avatars0.githubusercontent.com/u/79312?v=4" width="100px;"/><br /><sub><b>Mark Volkmann</b></sub>](http://ociweb.com/mark/)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Amvolkmann "Bug reports") [💻](https://github.com/gnapse/jest-dom/commits?author=mvolkmann "Code") |
-| [<img src="https://avatars1.githubusercontent.com/u/1659099?v=4" width="100px;"/><br /><sub><b>smacpherson64</b></sub>](https://github.com/smacpherson64)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=smacpherson64 "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=smacpherson64 "Documentation") [⚠️](https://github.com/gnapse/jest-dom/commits?author=smacpherson64 "Tests") | [<img src="https://avatars2.githubusercontent.com/u/132233?v=4" width="100px;"/><br /><sub><b>John Gozde</b></sub>](https://github.com/jgoz)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Ajgoz "Bug reports") [💻](https://github.com/gnapse/jest-dom/commits?author=jgoz "Code") | [<img src="https://avatars2.githubusercontent.com/u/7830590?v=4" width="100px;"/><br /><sub><b>Iwona</b></sub>](https://github.com/callada)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=callada "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=callada "Documentation") [⚠️](https://github.com/gnapse/jest-dom/commits?author=callada "Tests") | [<img src="https://avatars0.githubusercontent.com/u/840609?v=4" width="100px;"/><br /><sub><b>Lewis</b></sub>](https://github.com/6ewis)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=6ewis "Code") | [<img src="https://avatars3.githubusercontent.com/u/2339362?v=4" width="100px;"/><br /><sub><b>Leandro Lourenci</b></sub>](https://blog.lourenci.com/)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Alourenci "Bug reports") [📖](https://github.com/gnapse/jest-dom/commits?author=lourenci "Documentation") [💻](https://github.com/gnapse/jest-dom/commits?author=lourenci "Code") [⚠️](https://github.com/gnapse/jest-dom/commits?author=lourenci "Tests") | [<img src="https://avatars1.githubusercontent.com/u/626420?v=4" width="100px;"/><br /><sub><b>Shukhrat Mukimov</b></sub>](https://github.com/mufasa71)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Amufasa71 "Bug reports") |
+| [<img src="https://avatars1.githubusercontent.com/u/1241511?s=460&v=4" width="100px;" alt="Anto Aravinth"/><br /><sub><b>Anto Aravinth</b></sub>](https://github.com/antoaravinth)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=antoaravinth "Code") [⚠️](https://github.com/gnapse/jest-dom/commits?author=antoaravinth "Tests") [📖](https://github.com/gnapse/jest-dom/commits?author=antoaravinth "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/3462296?v=4" width="100px;" alt="Jonah Moses"/><br /><sub><b>Jonah Moses</b></sub>](https://github.com/JonahMoses)<br />[📖](https://github.com/gnapse/jest-dom/commits?author=JonahMoses "Documentation") | [<img src="https://avatars1.githubusercontent.com/u/4002543?v=4" width="100px;" alt="Łukasz Gandecki"/><br /><sub><b>Łukasz Gandecki</b></sub>](http://team.thebrain.pro)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=lgandecki "Code") [⚠️](https://github.com/gnapse/jest-dom/commits?author=lgandecki "Tests") [📖](https://github.com/gnapse/jest-dom/commits?author=lgandecki "Documentation") | [<img src="https://avatars2.githubusercontent.com/u/498274?v=4" width="100px;" alt="Ivan Babak"/><br /><sub><b>Ivan Babak</b></sub>](https://sompylasar.github.io)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Asompylasar "Bug reports") [🤔](#ideas-sompylasar "Ideas, Planning, & Feedback") | [<img src="https://avatars3.githubusercontent.com/u/4439618?v=4" width="100px;" alt="Jesse Day"/><br /><sub><b>Jesse Day</b></sub>](https://github.com/jday3)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=jday3 "Code") | [<img src="https://avatars0.githubusercontent.com/u/15199?v=4" width="100px;" alt="Ernesto García"/><br /><sub><b>Ernesto García</b></sub>](http://gnapse.github.io)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=gnapse "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=gnapse "Documentation") [⚠️](https://github.com/gnapse/jest-dom/commits?author=gnapse "Tests") | [<img src="https://avatars0.githubusercontent.com/u/79312?v=4" width="100px;" alt="Mark Volkmann"/><br /><sub><b>Mark Volkmann</b></sub>](http://ociweb.com/mark/)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Amvolkmann "Bug reports") [💻](https://github.com/gnapse/jest-dom/commits?author=mvolkmann "Code") |
+| [<img src="https://avatars1.githubusercontent.com/u/1659099?v=4" width="100px;" alt="smacpherson64"/><br /><sub><b>smacpherson64</b></sub>](https://github.com/smacpherson64)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=smacpherson64 "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=smacpherson64 "Documentation") [⚠️](https://github.com/gnapse/jest-dom/commits?author=smacpherson64 "Tests") | [<img src="https://avatars2.githubusercontent.com/u/132233?v=4" width="100px;" alt="John Gozde"/><br /><sub><b>John Gozde</b></sub>](https://github.com/jgoz)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Ajgoz "Bug reports") [💻](https://github.com/gnapse/jest-dom/commits?author=jgoz "Code") | [<img src="https://avatars2.githubusercontent.com/u/7830590?v=4" width="100px;" alt="Iwona"/><br /><sub><b>Iwona</b></sub>](https://github.com/callada)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=callada "Code") [📖](https://github.com/gnapse/jest-dom/commits?author=callada "Documentation") [⚠️](https://github.com/gnapse/jest-dom/commits?author=callada "Tests") | [<img src="https://avatars0.githubusercontent.com/u/840609?v=4" width="100px;" alt="Lewis"/><br /><sub><b>Lewis</b></sub>](https://github.com/6ewis)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=6ewis "Code") | [<img src="https://avatars3.githubusercontent.com/u/2339362?v=4" width="100px;" alt="Leandro Lourenci"/><br /><sub><b>Leandro Lourenci</b></sub>](https://blog.lourenci.com/)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Alourenci "Bug reports") [📖](https://github.com/gnapse/jest-dom/commits?author=lourenci "Documentation") [💻](https://github.com/gnapse/jest-dom/commits?author=lourenci "Code") [⚠️](https://github.com/gnapse/jest-dom/commits?author=lourenci "Tests") | [<img src="https://avatars1.githubusercontent.com/u/626420?v=4" width="100px;" alt="Shukhrat Mukimov"/><br /><sub><b>Shukhrat Mukimov</b></sub>](https://github.com/mufasa71)<br />[🐛](https://github.com/gnapse/jest-dom/issues?q=author%3Amufasa71 "Bug reports") | [<img src="https://avatars3.githubusercontent.com/u/1481264?v=4" width="100px;" alt="Roman Usherenko"/><br /><sub><b>Roman Usherenko</b></sub>](https://github.com/dreyks)<br />[💻](https://github.com/gnapse/jest-dom/commits?author=dreyks "Code") [⚠️](https://github.com/gnapse/jest-dom/commits?author=dreyks "Tests") |
 
 <!-- ALL-CONTRIBUTORS-LIST:END -->
 

src/__tests__/to-be-in-the-document.js

@@ -1,4 +1,5 @@
 import document from './helpers/document'
+import {HtmlElementTypeError} from '../utils'
 
 test('.toBeInTheDocument', () => {
   document.body.innerHTML = `
@@ -18,10 +19,24 @@ test('.toBeInTheDocument', () => {
   expect(nullElement).not.toBeInTheDocument()
 
   // negative test cases wrapped in throwError assertions for coverage.
-  expect(() => expect(htmlElement).not.toBeInTheDocument()).toThrowError()
-  expect(() => expect(svgElement).not.toBeInTheDocument()).toThrowError()
-  expect(() => expect(detachedElement).toBeInTheDocument()).toThrowError()
-  expect(() => expect(fakeElement).toBeInTheDocument()).toThrowError()
-  expect(() => expect(undefinedElement).toBeInTheDocument()).toThrowError()
-  expect(() => expect(nullElement).toBeInTheDocument()).toThrowError()
+  const expectToBe = /expect.*\.toBeInTheDocument/
+  const expectNotToBe = /expect.*not\.toBeInTheDocument/
+  expect(() => expect(htmlElement).not.toBeInTheDocument()).toThrowError(
+    expectNotToBe,
+  )
+  expect(() => expect(svgElement).not.toBeInTheDocument()).toThrowError(
+    expectNotToBe,
+  )
+  expect(() => expect(detachedElement).toBeInTheDocument()).toThrowError(
+    expectToBe,
+  )
+  expect(() => expect(fakeElement).toBeInTheDocument()).toThrowError(
+    HtmlElementTypeError,
+  )
+  expect(() => expect(undefinedElement).toBeInTheDocument()).toThrowError(
+    HtmlElementTypeError,
+  )
+  expect(() => expect(nullElement).toBeInTheDocument()).toThrowError(
+    HtmlElementTypeError,
+  )
 })

src/to-be-in-the-document.js

@@ -6,7 +6,7 @@ import {
 import {checkHtmlElement} from './utils'
 
 export function toBeInTheDocument(element) {
-  if (element !== null) {
+  if (element !== null || !this.isNot) {
     checkHtmlElement(element, toBeInTheDocument, this)
   }