(used to be "all tests must be live tests") Live tests are really good candidates to check if a production server is running
correctly. Some advices above can help, but there is some risk. Like it can be
possible to show to users data entered by tests. Some messages could be wrongly
sent to external software (like bank money transfer !). Some data entered by
users could be altered.
So some rules and good usage practice must be written to do live test on production environment in a safe way.
Here we will publish more informations once we have more experience with it.