Add coverage gathering

spec/script.lua

@@ -0,0 +1,38 @@
+#!/usr/bin/env lua
+local Parser = require "argparse"
+
+local parser = Parser()
+   :description "A testing program. "
+   :require_command(false)
+
+parser:argument "input"
+
+parser:flag "-v" "--verbose"
+   :description "Sets verbosity level. "
+   :target "verbosity"
+   :count "0-2"
+
+local install = parser:command "install"
+   :description "Install a rock. "
+
+install:argument "rock"
+   :description "Name of the rock. "
+
+install:argument "version"
+   :description "Version of the rock. "
+   :args "?"
+
+install:option "-f" "--from"
+   :description "Fetch the rock from this server. "
+   :target "server"
+
+parser:get_usage()
+parser:get_help()
+local args = parser:parse()
+
+print(args.input)
+print(args.verbosity)
+print(args.install)
+print(args.rock)
+print(args.version)
+print(args.server)