Cosmological tests are scientific experiments or observations that are conducted to test and validate theories and models of cosmology, the study of the structure, origin, evolution, and ultimate fate of the universe. These tests use a variety of methods and techniques, including observations of the cosmic microwave background radiation, measurements of the expansion rate of the universe, studies of the large-scale distribution of galaxies, and investigations of the nature and abundance of dark matter and dark energy. Overall, cosmological tests play a crucial role in advancing our understanding of the universe and determining the validity of different cosmological models and theories.