William Strunk's Elements of Style is a staple in AP English Language courses. The text itself can be found at http://www.bartleby.com/141/
Use this quiz either as a diagnostic test (with the follow-up activity customized for each student's needs) or as a summative assessment (with the follow-up activity customized to re-teach students what they missed.)
Each question on the quiz references the section of the text which presents the rule that students should have followed on the question. In the follow-up activity, students make corrections to the questions they missed using the Strunk rules.
Both the quiz and the follow-up activity include guidelines for awarding points.