No, these two cannot exist without one another. In order to know what kind of a curriculum is needed, you must also know what sorts of assessments you are going to be giving along the way.
In order for assessments to be worthwhile, they have to test the things that you have taught over the course of a unit or a semester or what have you. Conversely, a good lesson has to have good assessments that both measure student knowledge and help them retain that knowledge. Given these factors, it is clear that curriculum planning and assessment planning must go together. If this is done, the lessons and the assessments can be one seamless product that will enhance student learning.