make it possible to test bot w/o real HTTP requests/error #2
Description
With multiple test cases it takes much time to start/stop Bot API server (even mock), and make network calls, as this requires "talking to OS". Since this library will mostly be used in unit tests (which should be fast), it's necessary to allow mocking fetch, for example, that would make something like "response = botApi.request()" w/o real HTTP requests.