function zoneCountriesTest (zone) {
	var countries = zone.countries.slice().sort();
	return "\t\ttest.deepEqual(tz.zone('" + zone.name + "').countries(), [" +
		countries.map(function (code) { return '"' + code + '"' }).join(',') +
		"]);\n";
}
Creates a test for a zone's `.countries()` output