The Test Of Astronomy STandards (TOAST) is a comprehensive assessment instrument designed to measure students' general astronomy content knowledge. Built upon the research embedded within a generation of astronomy assessments designed to measure single concepts, the TOAST is appropriate to measure across an entire astronomy course. The TOAST's scientific content represents a consensus of expert opinion about what students should know from three different groups: the American Association for the Advancement of Science, the National Research Council, and the American Astronomical Society. The TOAST's reliability and validity are established by results from Cronbach alpha and classical test theory analyses, a review for construct validity, testing for sensitivity to instruction, and numerous rounds of expert review. As such the TOAST can be considered a valuable tool for classroom instructors and discipline based education researchers in astronomy across a variety of learning environments.