Do I need a production database to run integration tests?

Question

I'm trying to run integration tests on our CI server using a docker container. Now the documentation states that I only need to have a test-database (called magento_integration_tests), so I created that one.

But when running my integration test suite, I got the following error:

[PDOException]
SQLSTATE[HY000] [2002] No such file or directory

I fixed this by editing dev/tests/integration/etc/install-config-mysql.php and changing db-host from localhost to 127.0.0.1, but now the error got thrown again, only after a successful installation:

...
Write installation date...
[Progress: 529 / 529]
[SUCCESS]: Magento installation complete.
[SUCCESS]: Magento Admin URI: /backend

[Zend_Db_Adapter_Exception]
SQLSTATE[HY000] [2002] No such file or directory

I thought this error would have the same cause (with the localhost/127.0.0.1-issue described above), so I looked into the code where the exception was thrown (vendor/magento/zendframework1/library/Zend/Db/Adapter/Pdo/Abstract.php:148) and started var_dumping the configuration to see what was being used:

array(13) {
  'host' =>
  string(9) "localhost"
  'dbname' =>
  string(13) "[customer]-magento2"
  'username' =>
  ...

What's this? Apparently, at this point in the installation, the configuration of my shop is used to determine some information. But why? Could it be to copy some configuration settings from my actual webshop? I can only speculate for the reasons behind this.

Can anyone explain to me what's going on here? The documentation never mentions anything about the need for a production database for running integration tests. But in this setup it looks like it does!

Full stack trace:

Exception trace:
 () at /app/vendor/magento/zendframework1/library/Zend/Db/Adapter/Pdo/Abstract.php:148
 Zend_Db_Adapter_Pdo_Abstract->_connect() at /app/vendor/magento/zendframework1/library/Zend/Db/Adapter/Pdo/Mysql.php:111
 Zend_Db_Adapter_Pdo_Mysql->_connect() at /app/vendor/magento/framework/DB/Adapter/Pdo/Mysql.php:398
 Magento\Framework\DB\Adapter\Pdo\Mysql->_connect() at /app/vendor/magento/zendframework1/library/Zend/Db/Adapter/Abstract.php:460
 Zend_Db_Adapter_Abstract->query() at /app/vendor/magento/zendframework1/library/Zend/Db/Adapter/Pdo/Abstract.php:242
 Zend_Db_Adapter_Pdo_Abstract->query() at /app/vendor/magento/framework/DB/Adapter/Pdo/Mysql.php:517
 Magento\Framework\DB\Adapter\Pdo\Mysql->_query() at /app/vendor/magento/framework/DB/Adapter/Pdo/Mysql.php:580
 Magento\Framework\DB\Adapter\Pdo\Mysql->query() at /app/vendor/magento/zendframework1/library/Zend/Db/Adapter/Abstract.php:737
 Zend_Db_Adapter_Abstract->fetchAll() at /app/vendor/magento/module-store/Model/ResourceModel/Store.php:173
 Magento\Store\Model\ResourceModel\Store->readAllStores() at /app/generated/code/Magento/Store/Model/ResourceModel/Store/Interceptor.php:37
 Magento\Store\Model\ResourceModel\Store\Interceptor->readAllStores() at /app/vendor/magento/module-store/Model/Config/Processor/Fallback.php:89
 Magento\Store\Model\Config\Processor\Fallback->process() at /app/vendor/magento/module-config/App/Config/Type/System/Reader.php:60
 Magento\Config\App\Config\Type\System\Reader->read() at /app/generated/code/Magento/Config/App/Config/Type/System/Reader/Proxy.php:95
 Magento\Config\App\Config\Type\System\Reader\Proxy->read() at /app/vendor/magento/module-config/App/Config/Type/System.php:292
 Magento\Config\App\Config\Type\System->readData() at /app/vendor/magento/module-config/App/Config/Type/System.php:219
 Magento\Config\App\Config\Type\System->loadScopeData() at /app/vendor/magento/module-config/App/Config/Type/System.php:158
 Magento\Config\App\Config\Type\System->get() at /app/vendor/magento/framework/App/Config.php:131
 Magento\Framework\App\Config->get() at /app/vendor/magento/framework/App/Config.php:80
 Magento\Framework\App\Config->getValue() at /app/vendor/magento/module-developer/Model/Logger/Handler/Debug.php:63
 Magento\Developer\Model\Logger\Handler\Debug->isHandling() at /app/vendor/monolog/monolog/src/Monolog/Handler/AbstractProcessingHandler.php:29
 Monolog\Handler\AbstractProcessingHandler->handle() at /app/vendor/monolog/monolog/src/Monolog/Logger.php:337
 Monolog\Logger->addRecord() at /app/vendor/magento/framework/Logger/Monolog.php:48
 Magento\Framework\Logger\Monolog->addRecord() at /app/vendor/monolog/monolog/src/Monolog/Logger.php:616
 Monolog\Logger->error() at /app/vendor/magento/module-deploy/Console/Command/App/ConfigImport/Processor.php:151
 Magento\Deploy\Console\Command\App\ConfigImport\Processor->execute() at /app/vendor/magento/module-deploy/Console/Command/App/ConfigImportCommand.php:63
 Magento\Deploy\Console\Command\App\ConfigImportCommand->execute() at /app/vendor/symfony/console/Command/Command.php:242
 Symfony\Component\Console\Command\Command->run() at /app/setup/src/Magento/Setup/Console/Command/InstallCommand.php:151
 Magento\Setup\Console\Command\InstallCommand->execute() at /app/vendor/symfony/console/Command/Command.php:242
 Symfony\Component\Console\Command\Command->run() at /app/vendor/symfony/console/Application.php:842
 Symfony\Component\Console\Application->doRunCommand() at /app/vendor/symfony/console/Application.php:193
 Symfony\Component\Console\Application->doRun() at /app/vendor/magento/framework/Console/Cli.php:104
 Magento\Framework\Console\Cli->doRun() at /app/vendor/symfony/console/Application.php:117
 Symfony\Component\Console\Application->run() at /app/bin/magento:23

Answer 1

Magento integration tests framework requires an installed Magento instance to run a test suite. I will try to explain how it works in general:

1. On the initialization step dev/tests/integration/framework/bootstrap.php reads configuration from dev/tests/integration/phpunit.xml.
2. bootsrap.php initializes instance of \Magento\TestFramework\Application with TESTS_GLOBAL_CONFIG_DIR (contains the path to a "real" application etc folder, NOT test suite) from phpunit.xml.

3. If a test instance is not installed, then bootstrap.php calls install() method to install it.

   3.1. Application copies configuration files from "real" instance (that's why it needs TESTS_GLOBAL_CONFIG_DIR config option).

   3.2 Creates dump db from the "real" db (and again it uses configuration path from TESTS_GLOBAL_CONFIG_DIR) - that's why you see some data from your real database.

4. Runs test suite.

To solve your issue, you need to re-define TESTS_GLOBAL_CONFIG_DIR value (by default it ../../../app/etc, that's why test framework uses the same configuration as defined in the root application folder) in dev/tests/integration/phpunit.xml.dist.