The present Thesis is dedicated to the methods and tools of computer systems testing automation as well as estimation of their efficiency. Topical directions of automated testing evolution are overviewed, popular test automation tools are classified. Unified automated testing model is developed allowing to describe automatable activities of software testing on a high level. Mathematical model of automated testing efficiency estimation is developed allowing to achieve rational usage of a testing time. Automated test suite generation methods and adaptive performance testing methods are developed, providing the basis for developed tools, which were applied in the real testing projects. The Thesis consists of the introduction, six chapters and the conclusion. The first chapter describes historical evolution of automated testing, overviews several directions of test generation methods research and introduces developed classification of test automation tools used to classify 32 popular tools. The second chapter describes the development process of test automation tools and testware. Developed unified automated testing model is also described. The third chapter introduces the developed automated testing efficiency evaluation model. The fourth chapter describes developed solution for test suite generation. The fifth chapter describes developed performance testing tool and adaptive performance testing method. The sixth chapter overviews introduction and usage experience of the developed solutions described in the chapter four and five in real projects. The Thesis consists of 130 pages of text, 30 figures, 8 tables and 130 bibliographical references.