1. A method comprising: receiving an indication of an alteration to a first service; executing, by one or more computing devices, one or more service-level tests that test operability of the first service in isolation based at least in part on the receiving the indication of the alteration of the first service; determining that the operability of the first service in isolation satisfies a quality of service for the first service; determining, by at least one of the one or more computing devices, that a second service at least partially depends on the first service within a distributed-services environment; and executing, by at least one of the one or more computing devices, one or more integration-level tests that tests operability of the first service with respect to the second service within the distributed-services environment.