// Arrange & Act
        boolean result = UniAddress.isDotQuadIP(ip);
        // Assert
        assertTrue(result, "isDotQuadIP should return true for dot-quad IP");
    }

    @ParameterizedTest
    @ValueSource(strings = { "192.168.0", "abcd", "192.168" })
    void isDotQuadIPRejectsNonDotQuad(String value) {
        assertFalse(UniAddress.isDotQuadIP(value), "isDotQuadIP should return false for non IP-like values");
    }

    /**
     * Check whether a hostname is actually an ip address
     *
     * @param hostname the hostname to check
     * @return whether this is an IP address
     */
    public static boolean isDotQuadIP(final String hostname) {
        if (Character.isDigit(hostname.charAt(0))) {
            int i, len, dots;
            char[] data;

            i = dots = 0; /* quick IP address validation */