1. A method, comprising: receiving a test script that specifies (i) a failure scenario in a distributed microservice-based application comprising a plurality of microservices; and (ii) an asserted behavioral expectation of at least one microservice of the distributed microservice-based application in response to the specified failure scenario; translating the specified failure scenario into fault injection rules; and performing failure recovery testing during a run-time operation of the distributed microservice-based application by a process comprising: utilizing the fault, injection rules to execute fault injection operations on messages that are exchanged at a network layer between at least a first microservice and a second microservice of the distributed microservice-based application during the run-time operation of the distributed microservice-based application, by intercepting and manipulating messages that are exchanged at the network layer between the at least first and second microservices to stage the specified failure scenario during the run time operation of the distributed microservice-based application; and comparing the asserted behavioral expectation of the at least one microservice with an observed behavior of the at least one microservice in response to the execution of the fault injection operations.