The paper includes brief review of the main general problems of the testing automation for kJava applications. Existing approaches in the target area are reviewed. The differences between common kJava applications and system core kJava applications described. Demonstrated the necessity for the new testing automation solution for system core kJava applications. Use of internal structure of kJava implementation to create test automation system is described. The result is the test toolkit adapted for testing system core kJava applications. The results of using new method are shown.