Methods of error-tolerant modular testing of services are described, wherein an ordered list of test module identifiers is built in an error stack for the purposes of structured state teardown following the occurrence of an error during testing of services (i.e., network or other.) The error that triggers the teardown may comprise any error or more particularly an error not among a predetermined list of acceptable errors, the occurrence of which should not cause the cessation of services testing. Upon the occurrence of a triggering error, the test modules associated with the test module identifiers are executed in a reverse order to that which the test module identifiers were added to the error stack, effecting a structured state teardown.