Since the whole point of the helper is to check whether an arbitrary string is a valid country code supported by the library, we should accept any string here. For instance, the example code isSupportedCountry("XX") causes a compiler error, because "XX" is not part of the CountryCode union type.
Coverage remained the same at 100.0% when pulling 2f6589553c2e99a63496d8d288a1cd09349f0dc1 on richeterre:patch-1 into 44c75fc4fc956b0765bfea676c6bb2083536695d on catamphetamine:master.
Since the whole point of the helper is to check whether an arbitrary string is a valid country code supported by the library, we should accept any string here. For instance, the example code
isSupportedCountry("XX")
causes a compiler error, because "XX" is not part of theCountryCode
union type.