The Harvester runs on the Fuchsia device, acquiring Samples (units of introspection data) that it sends to the Host using the Transport system.
The Harvester should not unduly impact the Fuchsia device being monitored. So the Harvester does not store samples. Instead the samples are moved to the Dockyard as soon as reasonable.
Before running the tests, add //bundles:tests to your fx set (i.e. args.gn), then execute:
$ fx run-test system_monitor_harvester_tests
If the test is not already built, fx run-test will built it before running it.