Introduce test optimization

- Add static connection for whole tests
- Introduce ExtendedPDO class to enable nested transactions
- Add rollback logic for tests to ensure reliability and increase speed

tests/Util/Database/ExtendedPDO.php

@@ -0,0 +1,97 @@
+<?php
+
+namespace Friendica\Test\Util\Database;
+
+use PDO;
+use PDOException;
+
+/**
+ * This class extends native PDO one but allow nested transactions
+ * by using the SQL statements `SAVEPOINT', 'RELEASE SAVEPOINT' AND 'ROLLBACK SAVEPOINT'
+ */
+class ExtendedPDO extends PDO
+{
+	/**
+	 * @var array Database drivers that support SAVEPOINT * statements.
+	 */
+	protected static $_supportedDrivers = array("pgsql", "mysql");
+
+	/**
+	 * @var int the current transaction depth
+	 */
+	protected $_transactionDepth = 0;
+
+	/**
+	 * @return int
+	 */
+	public function getTransactionDepth()
+	{
+		return $this->_transactionDepth;
+	}
+
+	/**
+	 * Test if database driver support savepoints
+	 *
+	 * @return bool
+	 */
+	protected function hasSavepoint()
+	{
+		return in_array($this->getAttribute(PDO::ATTR_DRIVER_NAME),
+			self::$_supportedDrivers);
+	}
+
+
+	/**
+	 * Start transaction
+	 *
+	 * @return bool|void
+	 */
+	public function beginTransaction()
+	{
+		if($this->_transactionDepth == 0 || !$this->hasSavepoint()) {
+			parent::beginTransaction();
+		} else {
+			$this->exec("SAVEPOINT LEVEL{$this->_transactionDepth}");
+		}
+
+		$this->_transactionDepth++;
+	}
+
+	/**
+	 * Commit current transaction
+	 *
+	 * @return bool|void
+	 */
+	public function commit()
+	{
+		$this->_transactionDepth--;
+
+		if($this->_transactionDepth == 0 || !$this->hasSavepoint()) {
+			parent::commit();
+		} else {
+			$this->exec("RELEASE SAVEPOINT LEVEL{$this->_transactionDepth}");
+		}
+	}
+
+	/**
+	 * Rollback current transaction,
+	 *
+	 * @throws PDOException if there is no transaction started
+	 * @return bool|void
+	 */
+	public function rollBack()
+	{
+
+		if ($this->_transactionDepth == 0) {
+			throw new PDOException('Rollback error : There is no transaction started');
+		}
+
+		$this->_transactionDepth--;
+
+		if($this->_transactionDepth == 0 || !$this->hasSavepoint()) {
+			parent::rollBack();
+		} else {
+			$this->exec("ROLLBACK TO SAVEPOINT LEVEL{$this->_transactionDepth}");
+		}
+	}
+}