We present findings from an analysis of tests of teacher mathematical knowledge identified over a 20-year period of mathematics education literature. This analysis is part of a larger project aimed at developing a repository of instruments and their associated validity evidence for use in mathematics education. We report on how these tests are discussed in the literature, with a focus on validity arguments and evidence. A key finding is that these tests are often presented in ways that do not support their use by the mathematics education community. We offer suggestions on how adopting a validity argument perspective can enable others to build on initial test development efforts.