protected function sub_test_grade_category_qualifies_for_regrading()
 {
     $grade_category = new grade_category($this->grade_categories[1]);
     $this->assertTrue(method_exists($grade_category, 'qualifies_for_regrading'));
     $this->assertFalse($grade_category->qualifies_for_regrading());
     $grade_category->aggregation = GRADE_AGGREGATE_MAX;
     $this->assertTrue($grade_category->qualifies_for_regrading());
     $grade_category = new grade_category($this->grade_categories[1]);
     $grade_category->droplow = 99;
     $this->assertTrue($grade_category->qualifies_for_regrading());
     $grade_category = new grade_category($this->grade_categories[1]);
     $grade_category->keephigh = 99;
     $this->assertTrue($grade_category->qualifies_for_regrading());
 }