FAA AC 90-89B Amateur-Built Aircraft and Ultralight Flight Testing Handbook

Provides suggestions and safety-related recommendations to assist amateur and ultra-light builders in developing individualized aircraft flight test plans. It includes flight testing recommendations for canard-type and ultra-light aircraft.

Flight Testing Homebuilt Aircraft, Vaughan Askue

An excellent book by Vaughan Askue which details all aspects of flight testing. Available from Amazon.

Flight test info from Sequoia Aircraft

Articles from the Falco Builders Letter plus a guide to flight testing.

FAA AC23-8C Flight Test Guide for Certification of Part 23 Airplanes

FAA Advisory Circular 23-8C, Flight Test Guide for Certification of Part 23 Airplanes, is not mandatory for homebuilt aircraft.  But it may be interesting to learn how some flight tests are performed and what pass/fail criteria are used on type certificated light aircraft.  AC 23-8C must be read in conjunction with FAR 23.