Testing Web Services in the Cloud

This paper describes a tool supported process to test web services offered in the cloud against a service level agreement. After defining the goals of cloud service testing and reviewing previous approaches to testing web services, it goes on to define the particular problem of testing publically offered cloud services. The test is not directed at locating errors, but to evaluating the suitability of the service for a given application. To this end the requirements of the application, both functional und non-functional, have to be laid down in a service level agreement. The testing agent must extract the test criteria from that document to create a set of test cases. These requirement-based test cases are then matched to the cloud service interface definition to generate service test scripts. From the preconditions specified in the test script representative service requests are generated to be forwarded to the service under test in asynchronous modus. The responses from the service are collected in an output buffer to later be validated against the service post-conditions. Deviations between the expected and the actual results are reported. In the end a metric-based evaluation report is prepared to assist the user in deciding whether to use the service are not.