How does DataSource test in cakephp 2 - php

Question

We have custom DataSource and want to test that verifies the data after find method execute equals to one not customized.As I thought it, it would be possible if we can change Datasource in test code.I try many case, but I couldn't make it work.
public $default = [
'datasource' => 'CustomPostgres',
'persistent' => false,
'host' => 'localhost',
'port' => '5432',
'login' => 'hoge',
'password' => 'hogehoge',
'database' => 'prod',
'schema' => 'public',
'prefix' => '',
'encoding' => 'utf8'
];
public $test = [
'datasource' => 'CustomPostgres',
'persistent' => false,
'host' => 'localhost',
'port' => '5432',
'login' => 'hoge',
'password' => 'hogehoge',
'database' => 'test_prod',
'schema' => 'public',
'prefix' => '',
'encoding' => 'utf8'
];
public $old = [
'datasource' => 'Database/Postgres',
'persistent' => false,
'host' => 'localhost',
'port' => '5432',
'login' => 'hoge',
'password' => 'hogehoge',
'database' => 'dev',
'schema' => 'public',
'prefix' => '',
'encoding' => 'utf8'
];
public $test_old = [
'datasource' => 'Database/Postgres',
'persistent' => false,
'host' => 'localhost',
'port' => '5432',
'login' => 'hoge',
'password' => 'hogehoge',
'database' => 'test_dev',
'schema' => 'public',
'prefix' => '',
'encoding' => 'utf8'
];
//try1
$this->Model->setDataSource('test_old');
//try2
ConnectionManage::create('test_old',///);
//try3
////in fixture File and ClassRegistry:Init("Model")
$useDbConfig = "old";
////inner start::up
ClassRegistry:Init("Model");
//try4 extends model
ModelForOldSetting extends Model{
$useDbConfig = "old";
}
Above codes didn't work and it always emit error says
MissingConnectionException: Database connection "Postgres" is missing, or could not be created ,when running test however it works fine when setting default datasource Database/Postgres running local browser without test.
So, I'm really confused why Database connection "Postgres" is missing.Any idea makes me appreciate to them.

Answer 1

I finally found irritating and stupid irritating code by outer database.php file overrides datasources' setting.Following code works fine after appropriate settings.
ModelForOldSetting extends Model{
$useDbConfig = "dev";
$useTables = "models";
}
ClassRegistry:Init("ModelForOldSetting");
$model = $this->getMockForModel('ModelForOldSetting');