Merge pull request #143 from pyscript/add-test-details

Add test related details.

Author: ntoll

docs/developers.md

@@ -230,6 +230,28 @@ is through this environment that you contribute to PyScript.
     ```sh
     make test
     ```
+    
+    (This essentially runs the `npm run test:integration` command in the right
+    place. This is defined in PyScript's `package.json` file.)
+
+    Tests are found in the `core/tests` directory. These are organised into
+    three locations:
+
+    1. `python` - the Python based test suite to exercise Python code
+       **within** PyScript.
+    2. `javascript` - JavaScript tests to exercise PyScript itself, in the
+       browser.
+    3. `manual` - containing tests to run manually in a browser, due to the
+       complex nature of the tests.
+
+    We use [Playwright](https://playwright.dev/) to automate the running of the
+    Python and JavaScript test suites. We use
+    [uPyTest](https://github.com/ntoll/upytest) as a test framework for the
+    Python test suite. uPyTest is a "PyTest inspired" framework for running
+    tests in the browser on both MicroPython and Pyodide.
+
+    The automated (Playwright) tests are specified in the
+    `tests/integration.spec.js` file.
 
 ## Documentation