Add testing guide

README.md

@@ -17,6 +17,7 @@ This is the best* TeX-based mathematical plugin for CKEditor 5. You can use it t
 	* [From plain text](#from-plain-text)
 	* [From Microsoft Word](#from-microsoft-word)
 - [Preview workaround](#preview-workaround)
+- [Testing](#testing)
 - [Todo](#todo)
 
 ## Features
@@ -178,6 +179,16 @@ __.ck-reset_all *__ css rules from ckeditor5-ui and ckeditor5-theme-lark break r
 
 My solution for this is use rendering element outside of CKEditor DOM and place it right place by using absolute position. Alternative solution could be using iframe, but then we have to copy typesetting engine's scripts and styles to child document.
 
+## Testing
+
+Replace ckeditor5-core with git version
+
+`rm -rf node_modules/@ckeditor/ckeditor5-core && git clone https://github.com/ckeditor/ckeditor5-core.git node_modules/@ckeditor/ckeditor5-core`
+
+Run test suite
+
+`npm run test`
+
 ## Todo
 - MathML input and output when using MathJax version 3
 

package.json

@@ -22,6 +22,7 @@
     "@ckeditor/ckeditor5-dev-tests": "^16.9.0",
     "@ckeditor/ckeditor5-editor-inline": "^12.3.0",
     "@ckeditor/ckeditor5-essentials": "^11.0.5",
+    "@ckeditor/ckeditor5-paragraph": "^11.0.5",
     "eslint": "^5.5.0",
     "eslint-config-ckeditor5": "^2.0.0",
     "husky": "^1.3.1",