Merge pull request #13711 from Mugen87/dev1

Tests: Added README

Author: mrdoob

test/unit/README.md

@@ -0,0 +1,15 @@
+## Setup
+
+- Install [Node.js](https://nodejs.org/)
+- Execute `npm install`
+
+## Build
+
+- Execute `npm run build-test`
+
+## Run
+
+You can run the unit tests in two environments:
+
+- Node.js: Execute `npm run test`
+- Browser: Execute `npm run dev-test` and call `http://localhost:8080/test/unit/UnitTests.html` (see [How to run things locally](https://threejs.org/docs/#manual/introduction/How-to-run-things-locally))