These tests are used to detect changes in the schema of the JSON output for ffx commands. The JSON output is also called “machine output”. To get the machine output for a ffx command use the --machine top-level option with ffx. For example:
ffx --machine json-pretty target list
To generate the schema for the output use the --schema top-level option:
ffx --schema --machine json-pretty target list
These tests take a list of commands that the schema should be monitored for changes, and uses golden_files tests to detect changes.