+ which will start a webserver on port 9880 and auto-reloads
+ whenever you edit files. Configuration in `rollup.config.js`.
+
+## Testing
+
+The `test/` setup uses [Mocha](https://mochajs.org/) to run tests. Tests use [Puppeteer](https://pptr.dev/) to control a Google Chrome headless browser and evaluate with [Assert](https://nodejs.org/api/assert.html).
+
+
+* Run integration test suite (configuration in `.mocharc.js`)
+
+ ```
+ yarn test
+ API_ON_SAME_PORT=1 yarn test
+ ```
+
+ Setting API_ON_SAME_PORT simulates having both the API and UI on the same server
+ port. That's a rare setup but something https://nominatim.openstreetmap.org/ does
+ so worth testing.
+
+* Run syntax linter (configuration in `.eslint.js`)
+
+ ```
+ yarn lint
+ ```