DB switch between Production, Develop and Test in CakePHP3 - php-7

Question

I currently have two database settings in my config/app.php, one named "default" for production, another named "test" for development. I now want to rename the current "test" to "dev" and make a 3rd setting, naming it new "test" for testing purposes.
Switching between production database and development database is working fine, but how does my app know when to use the test database while I'm still in development environment (working on a development branch)? What changes should I make to what files?
I've been googling all day but all I can find is the way to switch between production and development. I need to know how to make the switch between development and test.
Below is something I have in mind but I'm pretty sure I have to modify some other files as well in order to make them work right.
# config/app.php
'Datasources' => [
// Production
'default' => [
'className' => 'Cake\Database\Connection',
'driver' => 'Cake\Database\Driver\Mysql',
'persistent' => false,
'host' => 'MY PRODUCTION HOST',
'username' => 'MY PRODUCTION USERNAME',
'password' => 'MY PRODUCTION PASSWORD'
'database' => 'MY PRODUCTION DATABASE NAME'
'quoteIdentifiers' => false,
// 'encoding' and so on...
],
// Development
'dev' => [
'className' => 'Cake\Database\Connection',
'driver' => 'Cake\Database\Driver\Mysql',
'persistent' => false,
'host' => 'MY DEVELOPMENT HOST',
'username' => 'MY DEVELOPMENT USERNAME',
'password' => 'MY DEVELOPMENT PASSWORD'
'database' => 'dev'
'quoteIdentifiers' => false,
// 'encoding' and so on...
],
// Test
'test' => [
'className' => 'Cake\Database\Connection',
'driver' => 'Cake\Database\Driver\Mysql',
'persistent' => false,
'host' => 'SAME AS MY DEVELOPMENT HOST',
'username' => 'SAME AS MY DEVELOPMENT USERNAME',
'password' => 'SAME AS MY DEVELOPMENT PASSWORD'
'database' => 'test'
'quoteIdentifiers' => false,
// 'encoding' and so on...
]
],
I'm totally new to CakePHP so any advices/suggestions would be appreciated. Thank you!

Answer 1

One method would be to set an environment variable in your development environment that's not set in production, for example:
DEV_ENVIRONMENT=true
In the application's startup script, in config/bootstrap.php you can look for that environment variable, and if it's set you can alias the default connection with dev:
In bootstrap.php:
// Look for this line:
ConnectionManager::setConfig(Configure::consume('Datasources'));
// Add your code someplace after that:
if(getenv('DEV_ENVIRONMENT')){
ConnectionManager::alias('dev', 'default');
}
The alias function will load the dev datasource any time the default connection is referenced in the app (which all Tables do unless overridden).
This generally the same method the PhpUnit tests use to substitute in the test datasource configs during test runs.