add section on how to run the tests

README.md

@@ -1,4 +1,4 @@
-# tween.js (r14) [![Travis tests](https://travis-ci.org/sole/tween.js.svg?branch=master)](https://travis-ci.org/sole/tween.js)
+# tween.js (r15dev) [![Travis tests](https://travis-ci.org/sole/tween.js.svg?branch=master)](https://travis-ci.org/sole/tween.js)
 
 **JavaScript tweening engine for easy animations**
 
@@ -140,6 +140,16 @@ Also, Jerome Etienne has written a [tutorial](http://learningthreejs.com/blog/20
 
 Finally, if you need to use tweens in C/C++ code, you now have an option! Check out [libtween](https://github.com/jsm174/libtween) which is a port of tween.js to C by [jsm174](https://github.com/jsm174)!
 
+## Running the tests
+
+You need to install `npm` first--this comes with node.js, so install that one first. Then, cd to `tween.js`'s directory and run:
+
+```bash
+npm test
+```
+
+If you want to add any feature or change existing features, you *must* run the tests to make sure you didn't break anything else. If you send a PR to add something new and it doesn't have tests, the PR won't be accepted (unless it's seriously good). See [contributing](CONTRIBUTING.md) for more info.
+
 ## Change log
 
 2014 06 15 - **r14** (5,798 KB, gzip: 2,168 KB)

package.json

@@ -30,5 +30,8 @@
     "gulp-rename": "^1.2.0",
     "gulp-uglify": "^0.3.1",
     "nodeunit": "^0.9.0"
+  },
+  "scripts": {
+    "test": "node_modules/.bin/nodeunit $(pwd)/test/unit/nodeunitheadless.js"
   }
 }