docs: fix the galaxy badge and describe the tests

The badge referenced the role id 58433 and linked to the unrelated role networking_role, so it neither showed the
download count of this role nor led anywhere useful. The heading is aligned with the galaxy role name as well.

Co-authored-by: Copilot <copilot@github.com>

README.md

@@ -1,6 +1,6 @@
-# sudo_users
+# volker-raschek.sudo
 
-[![Ansible Role](https://img.shields.io/ansible/role/d/58433)](https://galaxy.ansible.com/volker_raschek/networking_role)
+![Ansible Role](https://img.shields.io/ansible/role/d/volker-raschek/sudo)
 
 With following role can be created sudoers files in `/etc/sudoers.d`. For
 example to grant a user special perimssions to execute a program as root.
@@ -18,6 +18,42 @@ example to grant a user special perimssions to execute a program as root.
 - Installing sudo
 - Configuring drop-on files in `/etc/sudoers.d`
 
+## Tests
+
+The role is tested with [Molecule](https://ansible.readthedocs.io/projects/molecule/). The scenario starts one docker
+container per supported distribution family, applies the role, asserts that a second run reports no change and finally
+verifies the created drop-in files, their permissions and content, that a rule declared as `absent` is gone again and
+that `visudo` accepts the resulting configuration.
+
+Molecule ships only its `default` driver, therefore `docker` is required beside molecule itself. The collections are
+declared in `molecule/default/collections.yml` and installed by molecule.
+
+```bash
+pip install molecule docker
+```
+
+The complete sequence creates the containers, tests them and removes them afterwards.
+
+```bash
+molecule test
+```
+
+While working on the role the containers are better kept alive.
+
+```bash
+# create the containers and apply the role
+molecule converge
+
+# run the assertions of molecule/default/verify.yml against the running containers
+molecule verify
+
+# open a shell in one of the containers
+molecule login --host sudo-debian
+
+# remove the containers
+molecule destroy
+```
+
 ## Configuring
 
 In the default directory are examples how to configure the network stack. Copy the