Cognitive tools in learning and testing systems based on mixed diagnostic tests

E-learning systems and assessment of learning quality on these systems are briefly described. In order to improve the learning quality and the accuracy of his assessment is the use of different visualization tools, including cognitive. The approach based on mixed diagnostic tests and cognitive tools for creating the hybrid intelligent e-learning and testing system is given. This approach allows reducing cost and time of learning with improving of learning quality. The paper describes cognitive tools developed by us and their applying in learning systems, namely, 2- and 3-simplices, sector diagram with additional dependencies DiADep, circle diagram Target. Applying of these tools allows increasing assessment accuracy of learning quality, revealing new dependencies at learning process, investigating dynamic of learning, modeling influence of different factors on effectively of learning process, assessing of learning results of students. Future investigations are discussed.