Differences between assessment of learning and assessment for learning?

Assessmentof Learning - testing the knowledge retention when a a person is educated in a subject matter

Assessment for Learning - is establishing the skills level a person has before they undertake any learning. e.g. If training a person to measure 2 pieces of wood, fix together to gain a length that has to be cut to a final size it would be advisable to ensure that the person was familiar with basic maths as it will require addition and subtraction. If these basic skills are not there then the training to cut the wood will fail