Update jest.md

Author: MichaelCurrin

recipes/javascript/tests/jest.md

@@ -3,10 +3,11 @@
 
 See [Jest](https://jestjs.io/) homepage.
 
+Use the following pattern for placing naming your test scripts, so Jest can find them,.
 
-Test scripts should be named `*.spec.js`. You can also use `.jsx`, `.ts` or `.tsx` for the extension.
+- Scripts `tests/unit` that end in `.spec.(js|jsx|ts|tsx)`. e.g. `src/tests/unit/foo.spec.js`.
+- Any js(x)/ts(x) files inside `__tests__` directories. e.g. `src/__tests__/foo.test.js`.
 
-They can exist next to the script it is testing, or put all your tests in `__tests__`.
 
 
 ## Sample