Index: tests/phpunit/tests/db.php
===================================================================
--- tests/phpunit/tests/db.php	(revision 34383)
+++ tests/phpunit/tests/db.php	(working copy)
@@ -57,8 +57,8 @@
 	public function test_db_reconnect() {
 		global $wpdb;
 
-		$var = $wpdb->get_var( "SELECT ID FROM $wpdb->users LIMIT 1" );
-		$this->assertGreaterThan( 0, $var );
+		$connection = $wpdb->get_var( "SELECT CONNECTION_ID()" );
+		$this->assertGreaterThan( 0, $connection );
 
 		if ( $wpdb->use_mysqli ) {
 			mysqli_close( $wpdb->dbh );
@@ -65,10 +65,12 @@
 		} else {
 			mysql_close( $wpdb->dbh );
 		}
-		unset( $wpdb->dbh );
+		$wpdb->dbh = null;
 
-		$var = $wpdb->get_var( "SELECT ID FROM $wpdb->users LIMIT 1" );
-		$this->assertGreaterThan( 0, $var );
+		$newconnection = $wpdb->get_var( "SELECT CONNECTION_ID()" );
+		$this->assertGreaterThan( 0, $newconnection );
+
+		$this->assertNotEquals( $connection, $newconnection );
 	}
 
 	/**