Assessment is not just reserved for the formal occasions which are prescribed from on high! Assessment takes place in each class every day. It is a natural and integral part of the learning and teaching progress as effective, differentiated planning for development can't take place without such accurate assessment.
Teachers make more formal assessments at the end of units of work or at the end of a half term to provide information on progress and to ensure future learning. Children are "tracked" to make sure are making the appropriate level of progress and any slumps or dips can be challenged early and support put in place.
Assessment is not just done TO children, they are involved in their own assessment and learning through target setting, self moderation and evaluation and consistent marking and feedback. Children are aware of their own abilities and what they need to do to ensure next steps learning. this provides motivation and encoragement while supporting thier own self esteem.