Implementation of the filter mock feature. In contrast to the proposal in https://github.com/magnusbaeck/logstash-filter-verifier/issues/94#issuecomment-770877220 it was not possible to add the definition for the filter mocks into the test case file, because the mocks are needed to be applied to the "initial" config, which is loaded in the setup phase. Therefore I decided to put the mock filters into their own yaml config file, which can be specified optionally via command line flag.
Implementation of the filter mock feature. In contrast to the proposal in https://github.com/magnusbaeck/logstash-filter-verifier/issues/94#issuecomment-770877220 it was not possible to add the definition for the filter mocks into the test case file, because the mocks are needed to be applied to the "initial" config, which is loaded in the setup phase. Therefore I decided to put the mock filters into their own yaml config file, which can be specified optionally via command line flag.
Please merge #109 first.