We don't currently offer assessments for grading. We know that it's a necessary feature in the world of education today, but that idea does not relate well to our goal of trying to get students to learn and love computer science.
As the year goes on, we will be adding puzzles to measure how much improvement we see in a particular student, as well as adding tools for teachers to see the skills where students could use more practice. It is unlikely that either of those will be exclusively helpful for grading, however.
In the meantime, here is a post where various teachers discuss their options for assessments: