vlib: fix tcp_test.v

The listen_tcp method should not accept .unix af.
Test that it indeed fails when invoked.

vlib/net/tcp_test.v

@@ -1,20 +1,17 @@
-// vtest flaky: true
-// vtest retry: 8
 import net
-import os
 
 const test_port = 45123
 
-fn handle_conn(mut c net.TcpConn) {
+fn handle_conn(mut c net.TcpConn) ! {
 	for {
 		mut buf := []u8{len: 100, init: 0}
 		read := c.read(mut buf) or {
-			println('Server: connection dropped')
-			return
+			eprintln('Server: connection dropped')
+			return err
 		}
 		c.write(buf[..read]) or {
-			println('Server: connection dropped')
-			return
+			eprintln('Server: connection dropped')
+			return err
 		}
 	}
 }
@@ -24,40 +21,35 @@ fn one_shot_echo_server(mut l net.TcpListener, ch_started chan int) ! {
 	ch_started <- 1
 	mut new_conn := l.accept() or { return error('could not accept') }
 	eprintln('    > new_conn: ${new_conn}')
-	handle_conn(mut new_conn)
-	new_conn.close() or {}
+	handle_conn(mut new_conn)!
+	new_conn.close()!
 }
 
 fn echo(address string) ! {
 	mut c := net.dial_tcp(address)!
-	defer {
-		c.close() or {}
-	}
 
-	println('local: ' + c.addr()!.str())
-	println(' peer: ' + c.peer_addr()!.str())
+	eprintln('local: ' + c.addr()!.str())
+	eprintln(' peer: ' + c.peer_addr()!.str())
 
 	data := 'Hello from vlib/net!'
 	c.write_string(data)!
 	mut buf := []u8{len: 4096}
-	read := c.read(mut buf) or { panic(err) }
+	read := c.read(mut buf)!
 	assert read == data.len
 	for i := 0; i < read; i++ {
 		assert buf[i] == data[i]
 	}
-	println('Got "${buf.bytestr()}"')
+	c.close()!
 }
 
 fn test_tcp_ip6() {
 	eprintln('\n>>> ${@FN}')
-	address := 'localhost:${test_port}'
-	mut l := net.listen_tcp(.ip6, ':${test_port}') or { panic(err) }
+	address := '::1:${test_port}'
+	mut l := net.listen_tcp(.ip6, address) or { panic(err) }
 	dump(l)
 	start_echo_server(mut l)
 	echo(address) or { panic(err) }
-	l.close() or {}
-	// ensure there is at least one new socket created before the next test
-	l = net.listen_tcp(.ip6, ':${test_port + 1}') or { panic(err) }
+	l.close() or { panic(err) }
 }
 
 fn start_echo_server(mut l net.TcpListener) {
@@ -68,31 +60,21 @@ fn start_echo_server(mut l net.TcpListener) {
 
 fn test_tcp_ip() {
 	eprintln('\n>>> ${@FN}')
-	address := 'localhost:${test_port}'
+	address := '127.0.0.1:${test_port}'
 	mut l := net.listen_tcp(.ip, address) or { panic(err) }
 	dump(l)
 	start_echo_server(mut l)
 	echo(address) or { panic(err) }
-	l.close() or {}
+	l.close() or { panic(err) }
 }
 
 fn test_tcp_unix() {
 	eprintln('\n>>> ${@FN}')
-	// TODO(emily):
-	// whilst windows supposedly supports unix sockets
-	// this doesnt work (wsaeopnotsupp at the call to bind())
-	$if !windows {
-		address := os.real_path('tcp-test.sock')
-		// address := 'tcp-test.sock'
-		println('${address}')
-
-		mut l := net.listen_tcp(.unix, address) or { panic(err) }
-		start_echo_server(mut l)
-		echo(address) or { panic(err) }
-		l.close() or {}
+	address := 'tcp-test.sock'
+	eprintln('${address}')
 
-		os.rm(address) or { panic('failed to remove socket file') }
-	}
+	mut l := net.listen_tcp(.unix, address) or { return }
+	assert false
 }
 
 fn testsuite_end() {
@@ -103,6 +85,6 @@ fn test_bind() {
 	$if !network ? {
 		return
 	}
-	mut conn := net.dial_tcp_with_bind('vlang.io:80', '127.0.0.1:0')!
-	conn.close()!
+	mut conn := net.dial_tcp_with_bind('vlang.io:80', '127.0.0.1:0') or { panic(err) }
+	conn.close() or { panic(err) }
 }