Add support for SQLite :memory: databases.

lib/Connection.php

@@ -168,6 +168,7 @@ private static function load_adapter_class($adapter)
 	 * sqlite://../relative/path/to/file.db
 	 * sqlite://unix(/absolute/path/to/file.db)
 	 * sqlite://windows(c%2A/absolute/path/to/file.db)
+	 * sqlite://:memory:
 	 * </code>
 	 *
 	 * @param string $connection_url A connection URL
@@ -177,6 +178,9 @@ public static function parse_connection_url($connection_url)
 	{
 		$url = @parse_url($connection_url);
 
+		if ( $url['scheme'] == "sqlite" && $url['host'] == ":memory" )
+			$url['host'] = ":memory:";
+
 		if (!isset($url['host']))
 			throw new DatabaseException('Database host must be specified in the connection string. If you want to specify an absolute filename, use e.g. sqlite://unix(/path/to/file)');
 

lib/adapters/SqliteAdapter.php

@@ -15,13 +15,17 @@ class SqliteAdapter extends Connection
 {
 
 	static $datetime_format = 'Y-m-d H:i:s';
+	private static $cached_connection;
 
 	protected function __construct($info)
 	{
-		if (!file_exists($info->host))
+		if ($info->host != ":memory:" && !file_exists($info->host))
 			throw new DatabaseException("Could not find sqlite db: $info->host");
 
-		$this->connection = new PDO("sqlite:$info->host",null,null,static::$PDO_OPTIONS);
+		if ( self::$cached_connection == null ) {
+			self::$cached_connection = new PDO("sqlite:$info->host",null,null,static::$PDO_OPTIONS);
+		}
+		$this->connection = self::$cached_connection;
 	}
 
 	public function limit($sql, $offset, $limit)

test/SqliteAdapterMemoryTest.php

@@ -0,0 +1,30 @@
+<?php
+require_once __DIR__ . '/../lib/adapters/SqliteAdapter.php';
+require_once __DIR__ . '/SqliteAdapterTest.php';
+
+class SqliteAdapterMemoryTest extends SqliteAdapterTest
+{
+	public function set_up($connection_name=null)
+	{
+		$connections = ActiveRecord\Config::instance()->get_connections();
+    $connections['sqlite'] = 'sqlite://:memory:';
+		ActiveRecord\Config::instance()->set_connections( $connections );
+
+		parent::set_up();
+	}
+
+	public function testConnectToMemoryDatabaseShouldNotCreateDbFile()
+	{
+		try
+		{
+			ActiveRecord\Connection::instance("sqlite://:memory:");
+			$this->assertFalse(file_exists(__DIR__ . "/" . ":memory:" ));
+		}
+		catch (ActiveRecord\DatabaseException $e)
+		{
+			$this->fail("could not open connection to :memory: database");
+		}
+	}
+
+}
+?>