Hypothetically speaking, say you have a student that suffers from low self esteem. As a caring teacher, you want to do whatever it takes to make sure that this child stays happy. You go over some indepth material in class that is a bit challenging. When test time comes, do you fudge the test to make sure that it is passible.
Self esteem is discovered in the realization that ones self is valuable.
If a child were to realize that they were given something that they didnt deserve, such as a better test score, then that would only break down the existing self esteem they may have built up. Children need to realize that they are valuable not because they get good test scores, that is not what is important in this world. Build this childs self esteem by letting them know that you value them no matter what they achieve in your classroom. They might not be good in math, but there are so many other things in life that are important other than this class.