// Mixed case.
    checkPublicSuffix("COM", null)
    checkPublicSuffix("example.COM", "example.com")
    checkPublicSuffix("WwW.example.COM", "example.com")
    // Leading dot.
    checkPublicSuffix(".com", null)
    checkPublicSuffix(".example", null)
    checkPublicSuffix(".example.com", null)
    checkPublicSuffix(".example.example", null)
    // Unlisted TLD.