1. A system for evaluating performance of a network service, the system comprising: one or more computing systems configured to provide a control and reporting tier configured to: receive a request by way of a network service application programming interface (API) to perform testing on the network service, the request comprising data identifying a plurality of integration tests and test selection criteria; and in response to receiving the request, utilize the test selection criteria to select one or more integration tests from the plurality of integration tests, generate one or more load-generating jobs specifying the one or more integration tests, and provide the one or more load-generating jobs to a load-generating tier, wherein each of the one or more integration tests is tagged with a first annotation indicating that each integration test of the one or more integration tests is included in a suite of integration tests, wherein at least one of the one or more integration tests is tagged with a second annotation identifying a test parameter provider used by the at least one of the one or more integration tests, and wherein the first and second annotations are utilized in conjunction with the test selection criteria to select the one or more integration tests from the plurality of integration tests; and one or more other computing systems configured to: provide the load-generating tier, the load-generating tier comprising one or more load-generating instances configured to receive the one or more load-generating jobs and to execute the one or more integration tests to generate requests to the network service.