attribute_feature.test

@protobuf(proto3)
@jsonschema(id="https://example.org/mystruct1.json")

----------------------------------------------------

[
	["attribute", "@protobuf"],
	["punctuation", "("],
	"proto3",
	["punctuation", ")"],

	["attribute", "@jsonschema"],
	["punctuation", "("],
	"id",
	["operator", "="],
	["string-literal", [
		["string", "\"https://example.org/mystruct1.json\""]
	]],
	["punctuation", ")"]
]