Open faults are difficult to test since the voltage at the floating line is unpredictable and depends on the voltage at the adjacent lines. The effect of open faults can be easily excited if a test pattern provides the opposite logic value to most of the adjacent lines. In this paper, we present a procedure to generate as high a quality test as possible. We define the test quality for evaluating the effect of adjacent lines by assigning an opposite logic value to the faulty line. In our proposed test generation method, we utilize the SAT-based ATPG method. We generate test patterns that propagate the faulty effect to primary outputs and assign logic values to adjacent lines opposite that of the faulty line. In order to estimate test quality for open faults, we define the excitation effectiveness Eeff. To reduce the test volume, we utilize the open fault simulation. We calculate the excitation effectiveness by open fault simulation in order to eliminate unnecessary test patterns. The experimental results for the benchmark circuits prove the effectiveness of our procedure.