public function testXIndex()
{
// Translate a location in text1 to text2.
$this->d->setChanges(array(array(Diff::DELETE, "a"), array(Diff::INSERT, "1234"), array(Diff::EQUAL, "xyz")));
$this->assertEquals(5, $this->d->xIndex(2));
// Translation on deletion.
$this->d->setChanges(array(array(Diff::EQUAL, "a"), array(Diff::DELETE, "1234"), array(Diff::EQUAL, "xyz")));
$this->assertEquals(1, $this->d->xIndex(3));
}