A cloud streaming server test apparatus , comprising: virtual client modules configured to receive test results corresponding to a predetermined test script key input from cloud streaming servers and to create test result videos; a comparison unit ; and a test control unit configured to determine, based on a comparison result, if two compared images are not identical with each other that at least one of the cloud streaming servers has a failure, wherein the comparison unit is configured to request, under the control of the test control unit , a delivery of the test result videos created at each of the virtual client modules , to create at least one masked video by masking a part having animation in the test result videos, to create test result images by capturing the masked videos, to set a reference result image, to compare the created test result images with the reference result image by comparing a test result image, created by capturing a masked video corresponding to a reference server which is one of the cloud streaming servers with test result images created by capturing test result videos corresponding to other cloud streaming servers , and to output a comparison result to the test control unit , after a steady state condition is satisfied, wherein the steady state condition is an elapse condition of a predetermined time which is determined according to the predetermined test script key input, wherein the test control unit is further configured to change the reference server when a change condition for the reference server is satisfied, and if a number of cloud streaming servers determined as having failures before changing the reference server is greater, by a predetermined number or more, than a number of cloud streaming servers determined as having failures after changing the reference server , the test control unit is further configured to determine that there is a failure in the reference server before said server is changed. virtual client modules configured to receive test results corresponding to a predetermined test script key input from cloud streaming servers and to create test result videos; a comparison unit ; and a test control unit configured to determine, based on a comparison result, if two compared images are not identical with each other that at least one of the cloud streaming servers has a failure, wherein the comparison unit is configured to request, under the control of the test control unit , a delivery of the test result videos created at each of the virtual client modules , to create at least one masked video by masking a part having animation in the test result videos, to create test result images by capturing the masked videos, to set a reference result image, to compare the created test result images with the reference result image by comparing a test result image, created by capturing a masked video corresponding to a reference server which is one of the cloud streaming servers with test result images created by capturing test result videos corresponding to other cloud streaming servers , and to output a comparison result to the test control unit , after a steady state condition is satisfied, wherein the steady state condition is an elapse condition of a predetermined time which is determined according to the predetermined test script key input, wherein the test control unit is further configured to change the reference server when a change condition for the reference server is satisfied, and if a number of cloud streaming servers determined as having failures before changing the reference server is greater, by a predetermined number or more, than a number of cloud streaming servers determined as having failures after changing the reference server , the test control unit is further configured to determine that there is a failure in the reference server before said server is changed. <EOS>