This PR is the first in a series aimed at closing
[#15109](https://github.com/coder/coder/issues/15109).
### Changes
- **Template Database Creation:**
`dbtestutil.Open` now has the ability to create a template database if
none is provided via `DB_FROM`. The template database’s name is derived
from a hash of the migration files, ensuring that it can be reused
across tests and is automatically updated whenever migrations change.
- **Optimized Database Handling:**
Previously, `dbtestutil.Open` would spin up a new container for each
test when `DB_FROM` was unset. Now, it first checks for an active
PostgreSQL instance on `localhost:5432`. If none is found, it creates a
single container that remains available for subsequent tests,
eliminating repeated container startups.
These changes address the long individual test times (10+ seconds)
reported by some users, likely due to the time Docker took to start and
complete migrations.
* chore: add /v2 to import module path
go mod requires semantic versioning with versions greater than 1.x
This was a mechanical update by running:
```
go install github.com/marwan-at-work/mod/cmd/mod@latest
mod upgrade
```
Migrate generated files to import /v2
* Fix gen
* chore: rename `databasefake` to `dbfake`
* Remove unused method
* chore: add generation to dbfake
* Auto gen on make gen
* Fix preserving imports
* gen dbfake
* Add goimports
* Fix the makefile
* Make it panic instead of a comment
