added browser tests

CONTRIBUTING.md

@@ -6,7 +6,7 @@ By providing any kind of contribution to this project, **you must agree and be l
 
 ## Contributions
 
-Contributions by pull request or issues are welcome. Please ensure they follow the same style and architecture as the rest of the code. Use `npm run lint` before submitting. Please **do not include** any changes to the files in the `build` directory. 
+Contributions by pull request or issues are welcome. Please ensure they follow the same style and architecture as the rest of the code. Use `npm run lint` and see [Testing](#Testing) below before submitting. Please **do not include** any changes to the files in the `build` directory. 
 
 Before contributing please read the license agreement described at the beginning of this document.
 
@@ -22,6 +22,16 @@ which will install the required build dependencies, then run
 
 which will run the development server and opens `http://localhost:8000/` in your browser. Any changes you make to the source will automatically rebuild and reload the page.
 
+## Testing
+
+All contributions should pass when running the commands
+
+- `npm run lint`
+- `npm run test`
+- `npm run test-browser`
+
+The output of `npm run test` also includes a [comparison report](https://github.com/liabru/matter-js/pull/794), which highlights changes in results, performance and accuracy against the last release build.
+
 ## Commands
 
 The following development commands can be run at the terminal
@@ -33,8 +43,8 @@ creates a release build
 - **npm run lint**  
 runs the linter
 - **npm run test**  
-runs the tests
-- **npm run compare**  
-compares the output of examples for current source against release build
+runs the tests and compares results
+- **npm run test-browser**  
+runs the browser tests
 - **npm run doc**  
 builds the documentation

demo/js/Demo.js

@@ -99,6 +99,8 @@
         examples: examples
     });
 
+    window.MatterDemo = demo;
+
     document.body.appendChild(demo.dom.root);
 
     MatterTools.Demo.start(demo);