add a test

vlib/net/util.v

@@ -1,11 +1,12 @@
 module net
 
-const socket_max_port = u16(0xFFFF)
-
-// validate_port checks whether a port is valid
-// and returns the port or an error
+// validate_port checks whether a port is valid and returns the port or an error.
+// The valid ports numbers are between 0 and 0xFFFF.
+// For TCP, port number 0 is reserved and cannot be used, while for UDP, the source port
+// is optional and a value of zero means no port.
+// See also https://en.wikipedia.org/wiki/Port_%28computer_networking%29 .
 pub fn validate_port(port int) !u16 {
-	if port <= socket_max_port {
+	if port >= 0 && port <= 0xFFFF {
 		return u16(port)
 	} else {
 		return err_port_out_of_range

vlib/net/utils_test.v

@@ -0,0 +1,25 @@
+import net
+
+fn test_validate() {
+	assert net.validate_port(0)! == 0
+	assert net.validate_port(1)! == 1
+	assert net.validate_port(0xFFFF)! == 0xFFFF
+	if _ := net.validate_port(0xFFFF + 1) {
+		assert false
+	} else {
+		assert true
+	}
+	if x := net.validate_port(-2) {
+		dump(x)
+		assert false
+	} else {
+		assert true
+	}
+}
+
+fn test_resolve() {
+	x := net.resolve_addrs_fuzzy('[::1]:10093', .udp)!
+	assert x.len > 0
+	assert x[0].str() == '[::1]:10093'
+	assert x[0].port()! == 10093
+}