PURPOSE: To execute the test of the same contents many times by preserving and recycling test data, test process or tested result although the test of the same contents can not be executed many times in the case of executing the test of a conventional on-line program.

CONSTITUTION: This system is composed of a keyboard 1 for inputting test data, display 2 for displaying input contents, printer 3 for outputting the test data, test data file 7 for storing the inputted test data, test process file 8 for storing the keying information of the keyboard 1, tested result file 9 for storing the tested result, and test managing program 5 for managing these files. Then, a test object program 6 of the on-line program is tested by the test managing program 5, the temporarily tested test object program 6 is tested by the same process as the same test data many times. Each time the program is tested, the result is compared with the preceding tested result without checking all the result.