Default to panicking if a test accesses a real db

[matt2e]

We now have ftltest.WithDatabase(...) which switches the DSN to a <name>_test db (and wipes the db tables).
It can be hard to tell when writing tests if a real db is accidentally being used.
example: I'm trying to move pfi tests to use test dbs but it's pretty opaque without looking through each package carefully.

If there is a legitimate usecase for touching db's that havent been swapped with ftltest.WithDatabase we could add a option to allow it?

Thoughts?

[alecthomas]

How would we do this?

[matt2e]

• ftltest.WithDatabase(...) could mark the ModuleContext.Database as a test db.
• module context already knows if it is in a test context from ftltest
• So in modulecontext.GetDatabase(name), we can check for the case of moduleCtx.isTest && !database.isTestDB

[alecthomas]

Sounds like a good idea to me.