diff --git a/code/GoogleSitemap.php b/code/GoogleSitemap.php
index d56e4e8..8698993 100644
--- a/code/GoogleSitemap.php
+++ b/code/GoogleSitemap.php
@@ -93,6 +93,13 @@ class GoogleSitemap extends Controller {
 		return isset(self::$dataobjects[$className]);
 	}
 
+	/**
+	 * Clears registered dataobjects. Useful for unit tests.
+	 */
+	public static function clear_registered_dataobjects() {
+		self::$dataobjects = array();
+	}
+
 	/**
 	 * Returns a list containing each viewable {@link DataObject} instance of 
 	 * the registered class names.
diff --git a/tests/GoogleSitemapTest.php b/tests/GoogleSitemapTest.php
index 97d2846..697969d 100644
--- a/tests/GoogleSitemapTest.php
+++ b/tests/GoogleSitemapTest.php
@@ -22,6 +22,12 @@ class GoogleSitemapTest extends FunctionalTest {
 		}
 	}
 
+	public function tearDown() {
+		parent::tearDown();
+
+		GoogleSitemap::clear_registered_dataobjects();
+	}
+
 	public function testItems() {
 		$sitemap = new GoogleSitemap();