After all roles and playbooks have molecule test in place this optional optimization task could be done.

Including:

• check what parts of molecule.yml file content can be moved into common base conf molecule file
• Optimize/unify environment variable usage and check what variables could be populated from common env.yml file.

Using of base conf and env variables importing requires usage of molecule's command line options

--base-config <file>

--env-file <file>

and requires that running of tests always needs those parameters. But that can be handled in run wrapper.