Add formatter type 'str' where the string must be escaped, e.g. paths or
internal data. Otherwise plain %s can be printed if it's known that
there are no special characters.
Signed-off-by: David Sterba <dsterba@suse.com>
Add a simple framework to exercise the json formatter and add testing
target that validates the output.
Run 'make test-json' to execute all available tests, requires 'jq'
utility for validation (https://github.com/stedolan/jq).
Signed-off-by: David Sterba <dsterba@suse.com>