Introduce a "DatabaseException" class for fatal exceptions (used in testmode to throw an exception in case of DB errors)

src/Database/DatabaseException.php

@@ -0,0 +1,39 @@
+<?php
+declare(strict_types=1);
+
+namespace Friendica\Database;
+
+use Exception;
+use Throwable;
+
+/**
+ * A database fatal exception, which shouldn't occur
+ */
+class DatabaseException extends Exception
+{
+	protected $query;
+
+	/**
+	 * Construct the exception. Note: The message is NOT binary safe.
+	 *
+	 * @link https://php.net/manual/en/exception.construct.php
+	 *
+	 * @param string    $message  The Database error message.
+	 * @param int       $code     The Database error code.
+	 * @param string    $query    The Database error query.
+	 * @param Throwable $previous [optional] The previous throwable used for the exception chaining.
+	 */
+	public function __construct(string $message, int $code, string $query, Throwable $previous = null)
+	{
+		parent::__construct($message, $code, $previous);
+		$this->query = $query;
+	}
+
+	/**
+	 * {@inheritDoc}
+	 */
+	public function __toString()
+	{
+		return sprintf('Database error %d "%s" at "%s"', $this->message, $this->code, $this->query);
+	}
+}