docs: add setup information for Vue

Author: nickserv

docs/vue-testing-library/setup.mdx

@@ -3,4 +3,47 @@ id: setup
 title: Setup
 ---
 
-`Vue Testing Library` does not require any configuration to be used.
+`Vue Testing Library` does not require any configuration to be used. However,
+there are some things you can do when configuring your testing framework to
+reduce some boilerplate. In these docs we'll demonstrate configuring Jest, but
+you should be able to do similar things with
+[any testing framework](#using-without-jest) (Vue Testing Library does not
+require that you use Jest).
+
+## Using without Jest
+
+If you're running your tests in the browser bundled with webpack (or similar)
+then `Vue Testing Library` should work out of the box for you. However, most
+people using Vue Testing Library are using it with the Jest testing framework
+with the `testEnvironment` set to `jest-environment-jsdom` (which is the default
+configuration with Jest).
+
+`jsdom` is a pure JavaScript implementation of the DOM and browser APIs that
+runs in Node. If you're not using Jest and you would like to run your tests in
+Node, then you must install jsdom yourself. There's also a package called
+`jsdom-global` which can be used to setup the global environment to simulate the
+browser APIs.
+
+First, install `jsdom` and `jsdom-global`.
+
+```
+npm install --save-dev jsdom jsdom-global
+```
+
+With mocha, the test command would look something like this:
+
+```
+mocha --require jsdom-global/register
+```
+
+### Skipping Auto Cleanup
+
+[`Cleanup`](api.mdx#cleanup) is called after each test automatically by default
+if the testing framework you're using supports the `afterEach` global (like
+mocha, Jest, and Jasmine). However, you may choose to skip the auto cleanup by
+setting the `VTL_SKIP_AUTO_CLEANUP` env variable to 'true'. You can do this with
+[`cross-env`](https://github.com/kentcdodds/cross-env) like so:
+
+```
+cross-env VTL_SKIP_AUTO_CLEANUP=true jest
+```