1. A computer system comprising one or more processors, one or more computer-readable memories, one or more computer-readable storage devices, and program instructions, stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, the stored program instructions comprising: program instructions to read, responsive to load of a test script, a testbed description file for a particular testbed environment under test to identify a plurality of roles each specified by a separate role identifier of a plurality of role identifiers in the testbed description file and to identify one or more hosts from among a plurality of hosts assigned to each of the plurality of roles, wherein in the test script each separate operation refers to the separate role identifier only; program instructions to manage an interface through which a user views a logical view of the particular testbed environments displaying the plurality of hosts assigned to each of the plurality of roles; program instructions, in response to a user selection within the interface to adjust the logic view of a particular host from among the plurality of hosts assigned to a particular role from among the plurality of roles, to adjust the testbed description file to assign the particular host to the particular role; program instructions to instantiate, for each separate role identifier defined in the test script, a separate role identifier entity referring to a separate host description file for a separate host from among the plurality of hosts assigned to the separate role identifier in the testbed description file; and program instructions to manage, responsive to execution of the test script by an automation executor on the testbed environment, an abstraction between each separate role identifier referred to by each separate operation in the test script and each separate host currently hosting each separate role identifier for the testbed environment using the separate host description file instantiated for the separate role identifier entity for the separate host.