1. A system, for monitoring a web service, comprising: a processor executing computer readable instructions using a memory, and implementing at least a management module configured to provide an interface to input a test scenario and a policy for a simulation test of a target system; a database configured to store the received test scenario and policy; a service module configured to provide the stored test scenario and policy to the agent; an agent configured to monitor the target system by: accessing the target system according to the test scenario and the policy, carrying out the simulation test of the target system according to the policy, and generating the simulation test result; the service module further configured to provide the generated simulation test result to the management module; and the management module further configured to output the simulation test result.