public function testCompareVersions()
{
// Necessary to avoid
$oldCleanerClass = Diff::$html_cleaner_class;
Diff::$html_cleaner_class = 'SiteTreeTest_NullHtmlCleaner';
$page = new Page();
$page->write();
$this->assertEquals(1, $page->Version);
// Use inline element to avoid double wrapping applied to
// blocklevel elements depending on HTMLCleaner implementation:
// <ins><p> gets converted to <ins><p><inst>
$page->Content = "<span>This is a test</span>";
$page->write();
$this->assertEquals(2, $page->Version);
$diff = $page->compareVersions(1, 2);
$processedContent = trim($diff->Content);
$processedContent = preg_replace('/\\s*</', '<', $processedContent);
$processedContent = preg_replace('/>\\s*/', '>', $processedContent);
$this->assertEquals("<ins><span>This is a test</span></ins>", $processedContent);
Diff::$html_cleaner_class = $oldCleanerClass;
}