This test requires access to a local test site which can be upgraded.
1. Edit /mod/workshop/version.php and increase the $module->version to stimulate upgrade.
2. Rename /mod/chat to /mod/.chat to simulate a module missing from disk.
3. Download module (Dataform or some other module) from Moodle Plugins Directory
4. Unzip and copy that in /mod folder (Make sure to remove mod_ prefix from folder name)
5. Login as admin and go to your /admin page.
6. Check that the status of the Workshop module is 'upgrade needed'.
7. Check that the status of the Dataform module (or whatever module you downloaded) and its submodules is 'to be installed'.
8. Check that the status of the Chat module is 'missing from disk'.