Add a testing section in README

README.md

@@ -8,6 +8,7 @@ The repo depends on the latest plugin API (obsidian.d.ts) in Typescript Definiti
 **Note:** The Obsidian API is still in early alpha and is subject to change at any time!
 
 This sample plugin demonstrates some of the basic functionality the plugin API can do.
+
 -   Adds a ribbon icon, which shows a Notice when clicked.
 -   Adds a command "Open Sample Modal" which opens a Modal.
 -   Adds a plugin setting tab to the settings page.
@@ -53,11 +54,28 @@ Quick starting guide for new plugin devs:
 -   `npm i` or `yarn` to install dependencies.
 -   `npm run dev` to start compilation in watch mode.
 
+## Testing
+
+There is a setup for writing unit tests using [`Jest`](https://jestjs.io/). To run the test suite you can run
+
+```BASH
+npm run test
+```
+
+or in watch mode
+
+```BASH
+npm run test:watch
+```
+
+Due to the Obsidian source code not being open-source Jest's more common mocking patterns don't work, such as `jest.mock('obsidian')`. Instead we use [Jest's manual mocks](https://jestjs.io/docs/manual-mocks) by writing a partial mock module in [`__mocks__/obsidian.js`](./__mocks__/obsidian.js). Note that it does not contain a full mock of `obsidian` and you might need to extend it to test your plugin. If you do, please consider adding your extension to this repo.
+
 ## Manually installing the plugin
 
 -   Copy over `main.js`, `styles.css`, `manifest.json` to your vault `VaultFolder/.obsidian/plugins/your-plugin-id/`.
 
 ## Improve code quality with eslint (optional)
+
 -   [ESLint](https://eslint.org/) is a tool that analyzes your code to quickly find problems. You can run ESLint against your plugin to find common bugs and ways to improve your code.
 -   To use eslint with this project, make sure to install eslint from terminal:
     -   `npm install -g eslint`