How to Write Better Tests, Indiana University. General handbook, ranging from planning to formatting in first few pages.
Improving Essay Tests, William E. Cashin, Kansas State University. Comprehensive look at the essay test, including different types, their strengths and limitations, and how to properly construct one.
Improving Multiple-Choice Tests, Victoria L. Clegg & William E. Cashin, Kansas State University. In-depth look at how to create and improve multiple choice questions, including dozens of recommendations for a professor to keep in mind.
Improving Validity of Large-scale Tests: Universal Design and Student Performance, Christopher J. Johnstone, National Center on Educational Outcomes. Lots of information 1/4 down the page related to the seven elements of UDL, including a table on characteristics of legible type. Tested with K12 students, but relevant nonetheless.
Improving Your Test Questions, Center for Innovation in Teaching & Learning, University of Illinois at Urbana-Champaign. When to pick Objective vs. Subjective, how to write strong questions, and ways assess test item quality.
Validity and Reliability, Bruce A. Craig, Purdue University. Document with definitions of various types of test validity and reliability.