How can I enable IDE integration (autocomplete) for WordPress test suite

When testing a theme or plugin, you can use WP-CLI to scaffold the test suite setup, wp scaffold plugin-test plugin.

So is there a good way to integrate an editor/IDE (VS Code in my case) so that autocompletion (method signatures, etc) works within the tests? Since the test library is installed in /tmp/ the editor is not indexing those files and thus thinks classes and functions are missing.