A teacher can use marking workflow to control release of grades to students

This test requires a course with a teacher and student enrolled. Marking workflow should be enabled site wide from Site administration>Plugins>Activity modules>Assignment>Assignment settings

1) Log in as a teacher and create a simple text assignment.
2) In the Grade section, set Use Marking workflow to 'Yes' and save the assignment.
3) Log in as a student and type a short phrase to do do the assignment.
4) Log in as the teacher; give it a grade and set the Marking workflow state to 'In marking.'
5) Log in as the student; access the assignment and verify that the Marking status is 'In marking', but you cannot see the grade either on the assignment page or from Course administration>Grades.
6) Log in as the teacher; access the assignment and set the Marking workflow state to 'Marking complete.'
7) Repeat step 5 for the student, verifying that the Marking status is 'Marking Complete', but you still cannot see your grade.
8) Log in as the teacher; access the assignment and set the Marking workflow state to 'Released.'
9) Repeat step 5 for the student, verifying you can now see your grade both on the assignment page and from Course administration>Grades.