diff --git a/main/gradebook/lib/fe/gradebooktable.class.php b/main/gradebook/lib/fe/gradebooktable.class.php
index 280c15cc28..e52fa44e31 100755
--- a/main/gradebook/lib/fe/gradebooktable.class.php
+++ b/main/gradebook/lib/fe/gradebooktable.class.php
@@ -551,7 +551,7 @@ class GradebookTable extends SortableTable
             // evaluation
             case 'E' :
                 $cat = new Category();
-                $course_id = Database::get_course_by_category($_GET['selectcat']);
+                $course_id = CourseManager::get_course_by_category($_GET['selectcat']);
 
                 $show_message = $cat->show_message_resource_delete($course_id);
 
@@ -588,7 +588,7 @@ class GradebookTable extends SortableTable
             // link
             case 'L' :
                 $cat 			= new Category();
-                $course_id	 	= Database::get_course_by_category($_GET['selectcat']);
+                $course_id	 	= CourseManager::get_course_by_category($_GET['selectcat']);
                 $show_message	= $cat->show_message_resource_delete($course_id);
 
                 $url = $item->get_link();
diff --git a/tests/main/inc/lib/database.lib.test.php b/tests/main/inc/lib/database.lib.test.php
index 973772eccf..0c7407d08b 100755
--- a/tests/main/inc/lib/database.lib.test.php
+++ b/tests/main/inc/lib/database.lib.test.php
@@ -98,12 +98,6 @@ class TestDatabase extends UnitTestCase {
 	}
 	*/
 
-	function get_course_by_category() {
-		$category_id='1';
-		$res=$this->dbase->get_course_by_category($category_id);
-		$this->assertTrue(is_string($res));
-	}
-
 	function testGetCourseInfo() {
 		$course_code='AYDD';
 		$res=$this->dbase->get_course_info($course_code);