Formulaic language is a crucial component of language overall, and therefore merits the development of tests capable of yielding valid and reliable scores. However, the diverse nature of formulaic language poses challenges for test design. This chapter will critique existing tests of formulaic language and discuss principles for the development of future tests. Key issues include construct definition, the need to develop tests for particular purposes, identification and selection of target formulaic sequences, sampling rate, choice of item format, and using technology.